Table of Content

18 August 2016, Volume 27 Issue 8

Previous Issue    Next Issue

CONTENTS

Accumulation responses of seeds and seedlings to ¹⁵N isotope for two typical broadleaved trees in Northeast China.

WANG Guang-chen, SONG Yuan, YAN Qiao-ling, ZHANG Jin-xin

2016, 27(8):  2379-2389.  doi:10.13287/j.1001-9332.201608.030

Asbtract ( 363 )   PDF (939KB) ( 20 )  

Two typical broadleaved trees (i.e., Fraxinus rhynchophylla and Acer mono) with wind-dispersed seeds in Northeast China were selected in this study. A method of ¹⁵N isotope labeling was used to explore the accumulation responses of seeds and seedlings to ¹⁵N-urea soaking concentration (0, 0.05, 0.1 and 0.2 g·L^-1), soaking time (4, 8 and 12 days) and leaf stage (2, 4, 6, and 8 leaves). The results showed that ¹⁵N-urea soaking concentration and soaking time had significantly positive effects on δ¹⁵N values of seeds, i.e., higher ¹⁵N-urea concentration and longer period of soaking (0.2 g·L^-1+12 d) were contributed to more ¹⁵N accumulation of seeds. The maximum multiples of ¹⁵N accumulation in F. rhynchophylla seeds and A. mono seeds were observed in 0.1 g·L^-1+ (4 d, 8 d) and 0.05 g·L^-1+ (4 d, 8 d), respectively. The loss rate of δ¹⁵N values decreased markedly from 2 leaves to 6 leaves and then kept relatively stable with the increasing seedling height, and the total δ¹⁵N values of seedlings started to decline at the stage of 8 leaves. These results suggested that seedlings with 6 leaves were more suitable for tracking seedling source. The δ¹⁵N values in leaves of seedlings were significantly positively correlated with ¹⁵N-urea concentration level, soaking time and δ¹⁵N values of seeds. Overall, the accumulation of ¹⁵N-urea could be found in seeds and seedlings of F. rhynchophylla and A. mono. The combination of ¹⁵N-urea concentration (0.1 g·L^-1), soaking time (8 d) and leaf stage (6 leaves) was the most suitable for tracking the seeds and seedlings of these two broadleaved trees.

Effects of environmental factors on evapotranspiration characteristics of Haloxylon ammodendron plantation in the Minqin oasis-desert ectone, Northwest China.

ZHANG Xiao-yan, CHU Jian-min, MENG Ping, ZHENG Ning, YAO Zeng-wang, WANG He-song, JIANG Sheng-xiu

2016, 27(8):  2390-2400.  doi:10.13287/j.1001-9332.201608.034

Asbtract ( 330 )   PDF (1498KB) ( 27 )  

This study continuously measured the evapotranspiration (ET) of degraded Haloxylon ammodendron shrub plantation of Minqin oasis-desert ectone using an eddy covariance system for ET, and TDR for soil moisture profile, analyzing ET in relation to the weather conditions and describing the responses of ET to the microclimate variables in different weather from July 2014 to June 2015. Results showed that the hourly ET dynamics had an apparent seasonal trend in the growing season. This trend gradually increased in the beginning of season from the low level of non-growing season, reached its maximum peak value (0.07 mm·h^-1) in the most physiologically active period, and decreased to the minimum peak value (0.01 mm·h^-1) in December. The diurnal change in ET of the plantation depended on the weather conditions. The ET fluctuated less with a small magnitude in a cloud day, but fluctuated obviously with a greater magnitude after rain if weather was clear. After a strong rainfall (>9 mm·d^-1), ET increased sharply to a high level of 28 folds prior to rain, at which it took four clear days to gradually decease to the pre-rain ET level. The yearly ET over H. ammodendron plantation was 108 mm, equivalent to 98% of annual precipitation. Soil moisture was the water source for ET. Therefore, soil moisture was the dominant factor for theET over the plantation. Net radiation, photosynthesis active radiation, air temperature, and vapor pressure deficit were the microclimate variables to drive the transpiration of vegetation and evaporation over the soil surface, being the major factors forET over the plantation. The regression equation of ET to the dominant factor and major factors had a coefficient of multiple determination (R²) over 0.80.

Prediction of potential distribution area of the spruce forest on the central Tianshan Mountain based on site index.

DING Cheng-feng, LI Xia, ZHANG Hui-fang, GAO Ya-qi, LI Wei-tao

2016, 27(8):  2401-2408.  doi:10.13287/j.1001-9332.201608.038

Asbtract ( 319 )   PDF (3283KB) ( 17 )  

This paper predicted the potential distribution area of the spruce forest on the central Tianshan Mountain, through determining the site index thresholds, using 3S and spatial modeling technologies to build a site index model with water, heat, terrain and other factors, based on the current site conditions there. The results showed that the potential distribution area simulated by the site index model was not significantly different with the current actual distribution area, but had a significant difference with the non-spruce forest area. Based on the built site index model, there was a large potential distribution area, which occupied 6.4% of the total research area, i.e., 7.01×10³ hm² of forest lower boundary zones, glades, shady and half shady slope areas, and could be used for the future forest development.

Monitoring temporal dynamics in leaf area index of the temperate broadleaved deciduous forest in Maoershan region, Northeast China with tower-based radiation measurements.

LIU Fan, WANG Chuan-kuan, WANG Xing-chang

2016, 27(8):  2409-2419.  doi:10.13287/j.1001-9332.201608.031

Asbtract ( 409 )   PDF (1426KB) ( 11 )  

Broadband vegetation indices (BVIs) derived from routine radiation measurements on eddy flux towers have the advantage of high temporal resolutions, and thus have the potential to obtain detailed information of dynamics in canopy leaf area index (LAI). Taking the temperate broadleaved deciduous forest around the Maoershan flux tower in Northeast China as a case, we investigated the controlling factors and smoothing method of four BVI time-series, i.e., broadband norma-lized difference vegetation index (NDVI_B), broadband enhanced vegetation index (EVI_B), the ratio of the near-infrared radiation reflectance to photosynthetically active radiation reflectance (SR_NP), and the ratio of the shortwave radiation reflectance to photosynthetically active radiation reflectance (SR_SP). We compared the seasonal courses of the BVIs with the LAI based on litterfall collection method. The values for each BVI were slightly different among the three calculation methods by Huemmrich, Wilson, and Jenkins, but showed similar seasonal patterns. The diurnal variations in BVIs were mainly influenced by the solar elevation and the angle between the solar elevation and slope, but the BVIs were relatively stable around 12:30. The noise of daily BVI time-series could be effectively smoothed by a threshold of clearness index (K). The seasonal courses of BVIs for each time of day around the noon had similar patterns, but their thresholds of K and the percen-tages of remaining data were different. Therefore, the daily values of BVIs might be optimized based on the smoothing and the proportion of remaining data. The NDVI_B was closely correlated linearly with the LAI derived from the litterfall collection method, while the EVI_B, SR_NP, and SR_SP had a logarithmic relationship with the LAI. The NDVI_B had the advantage in tracking the seasonal dyna-mics in LAI and extrapolating LAI to a broader scale. Given that most eddy flux towers had equipped with energy balance measurements, a network of monitoring canopy LAI could be readily achieved if the reflectance of photosynthetically active radiation was measured synchronously.

Optimal model of photosynthesis-light response curve in canopy of planted Larix olgensis tree.

LIU Qiang, LI Feng-ri, XIE Long-fei

2016, 27(8):  2420-2428.  doi:10.13287/j.1001-9332.201608.023

Asbtract ( 346 )   PDF (786KB) ( 22 )  

Rectangle hyperbola model (RH), nonrectangle hyperbola model (NRH), exponential model (EM), modified rectangle hyperbola model (MRH), and modified exponential model (MEM) were applied respectively for modeling the photosynthesis-light response curves (PLC) based on four types of curves (photosynthesis-light response curve of inhibition, PLC_i, photosynthesis-light response curve of saturation, PLC_s, photosynthesis-light response curve of unsaturation, PLC_u andphotosynthesis-light response curve in weak light, PLC_w) in canopy of 15 years old planted Larix olgensis tree in the Maoershan Forest Farm, Heilongjiang Province. The major photosynthetic physiological indexes including maximum net photosynthetic rate (P_{n max}), dark respiration rate (R_d), light compensation point (LCP), light saturation point at saturated light intensity (LSP) and apparent quantum yield (AQY) were calculated. All the five candidate models were comprehensively compared by the model goodness-of-fit and the precision estimations of photosynthetic physiological indexes in the four types of curves. The results showed that MEM model was only suitable for fitting the PLC_i. MRH model showed the best goodness-of-fit for PLC_i and PLC_s(R_a²was 0.9986 and 0.9978, respectively). Meanwhile, NRH model expressed the best fitting result in PLC_u and PLC_w (R_a² was 0.9996 and 0.9963, respectively). MRH had the lowest mean absolute value of relative error (MAPE) when evaluating P_{n max} in different types of curves (0.1%<MAPE<0.7%), but its precision estimation for LCP was relatively worse (2.5%<MAPE<9.4%). NRH model exhibited more accurate estimation for LCP of PLC_s and PLC_u, as well as R_d of PLC_u(MAPE was 1.8%, 0.1%, and 3.9%, respectively). RH model represented better prediction effect for LCP of PLC_i and R_d of PLC_s(MAPE was 1.0% and 2.7%, respectively). EM was more sui-table for estimating LCP of PLC_w(MAPE was 0.2%). Comprehensive analysis showed that MRH model not only proved well model goodness-of-fit and accurate estimation of photosynthetic physiological indexes, but also showed the highest stability when fitting different types of curves. As a result, MRH model was finally selected as the optimal canopy photosynthesis-light response model of planted L. olgensis tree.

Modeling the diameter distribution of Larix olgensis plantation based on thinning effects.

WANG Meng, LI Feng-ri

2016, 27(8):  2429-2437.  doi:10.13287/j.1001-9332.201608.026

Asbtract ( 411 )   PDF (654KB) ( 21 )  

In 1974, five permanent sample plots of Larix olgensis plantation were established in Mengjiagang forest farm in Heilongjiang Province, which included one control plot and four thinning plots with different thinning treatments (remove 3.7%-49.7% of the basal area). Diameter at breast height (DBH) for each tree (19-59 a) of the five plots was remeasured 31 times from 1974 to 2014. The three parameters Weibull function was used to describe the DBH distribution of different ages for the five plots. The dynamic changes and the effects of thinning on the diameter distribution curves and the three parameters of Weibull function were analyzed. Based on the thinning effects, the parameter prediction model (PPM) of simultaneous equations system was developed and the parameters were estimated by three-stage least squares method (3SLS) and error-in-variable method of simultaneous equations. The results showed that the diameter distribution curves with stand age changed from higher peak with narrow DBH range to lower peak with large DBH range for unthinned stand (control plot). For thinning plots, the skewness was more right-hand with higher peak, narrow DBH range, and increased asymmetry of the curves after thinning. Increasing with thinning intensity, more trees of small or middle sizes were cut and the curves of diameter distribution were obvious left-truncted higher peak with narrow DBH range than before thinning. The parameter a of the Weibull function increased with thinning intensity and the parameter b decreased. The parameter c was not influenced by lower intensity thinning, but decreased by higher thinning intensity. The fitting results for the PPM of simultaneous equations system showed that predicting models for the parameter b were best (R²>0.98) and the R² for model of the parameter c was larger than 0.91. The method of 3SLS was as good as the error-in-variable method, and there was no significant diffe-rence. The results of validation for the two methods showed that, the precision of the three prediction models was >97%, and the fitting efficiency (EF) was >0.92. The parameter prediction mo-dels developed based on the effects of thinning performed well and could be used to predict the dynamic change of diameter distribution and to provide suitable management of L. olgensis plantation.

Ionic homeostasis of Populus ×euramericanna ‘Neva’ influenced by irrigation with magne-tized brackish water.

LIU Xiu-mei, GUO Jian-yao, ZHU Hong, WAN Xiao, WANG Lu, WANG Hua-tian, MA Feng-yun, ZHONG Feng-wei

2016, 27(8):  2438-2444.  doi:10.13287/j.1001-9332.201608.039

Asbtract ( 351 )   PDF (603KB) ( 17 )  

The research aimed to study the characteristic of ionic homeostasis of annual seedlings of Populus ×euramericanna under irrigation with non-magnetized and magnetized 0 or 4.0 g·L^-1 NaCl solution for 30 days in the growing season. The ion contents of K⁺, Na⁺, Ca²⁺ and Mg²⁺ in the lea-ves and roots were measured by atomic absorption spectrophotometry (AAS). The ion homeostasis coefficient (K) and the ion selective transport coefficient (S_Xi,Na) from root system to leaves were analyzed. Compared with the unsalted treatment, the ion contents of Na⁺ and Ca²⁺, S_K,Na and S_Mg,Na increased in leaves and roots under NaCl stress, while the K⁺ and Mg²⁺ ion content, the ratio of K⁺/Na⁺ and S_Ca,Na decreased. Compared with the non-magnetized NaCl solution (NM), the magnetized NaCl solution (M) made leaves and roots maintain lower content of Na⁺ but higher content of K⁺ and the K⁺/Na⁺. Compared with the NM, the content of Ca²⁺ decreased while that of Mg²⁺ increased in the M. In M, K was higher than that in NM, and there was significant increase in the leaves than that in the roots. The ratios of S_K,Na and S_Mg,Na in leaves and roots in M were higher than those in NM, while the ratio of S_Ca,Na was lower. The magnetized NaCl solution decreased Na⁺ content, increased K⁺, Ca²⁺ and Mg²⁺ content, and maintained higher K⁺/Na⁺, which was beneficial for the physiological metabolism of the whole plant. So, the magnetic effect could promote the re-establishment of ionic homeostasis by ions selective absorption and transportation under NaCl stress.

Effects of elevated temperature and CO₂ concentration on growth and leaf quality of Morus alba seedlings.

ZENG Zhen, HUAN Hui-hui, LIU Gang, XIAO Juan, HUANG You-you, XU Xiao, DONG Ting-fa

2016, 27(8):  2445-2451.  doi:10.13287/j.1001-9332.201608.022

Asbtract ( 270 )   PDF (607KB) ( 11 )  

To estimate the potential effects of climate change on the growth and leaf quality of Morus alba, one-year-old M. alba seedlings were exposed 60 d under four treatments, i.e., elevated temperature (ET, +2 ℃), elevated CO₂ concentration (EC, +300 ppm CO₂), elevated temperature and CO₂ concentration (ETC, +2 ℃ & +300 ppm CO₂), and control treatment (CK). The results showed that basal diameter, leaf number, total leaf area, leaf dry mass, leaf dry mass fraction and soluble protein were 9.9%, 17.4%, 23.0%, 9.2%, 10.1% and 23.1% higher under ET than those under CK, respectively. EC significantly increased the stem, root and total dry biomass by 10.7%, 15.9% and 9.2% compared with CK, respectively, whereas leaf quality was similar between EC and CK. Compared with CK, leaf number, height, diameter, total leaf area, the leaf, root and total dry biomass, leaf soluble sugar content and crude protein content increased significantly by 28.8%, 9.1%, 19.4%, 32.6%, 12.4%, 17.2%, 10.1%, 45.8% and 11.9% in ETC while the leaf crude fibre content decreased by 16.8%. Our results indicated that climate change had a positive effect on the growth and leaf quality of M. alba in a short period.

Effects of different mulching materials on nitrate metabolism in soil of apple root-zone in summer and autumn.

ZHANG Rui-xue, YANG Hong-qiang, XU Ying, LYU Ting-wen, CAO Hui, NING Liu-fang, ZHOU Chun-ran, FAN Wei-guo

2016, 27(8):  2452-2458.  doi:10.13287/j.1001-9332.201608.014

Asbtract ( 297 )   PDF (831KB) ( 15 )  

This study explored the effects of mulching straw mat, agricultural carpet, transparent-plastic film and horticultural fabric on nitrification-denitrification, nitrate reductase (NR), nitrite reductase (NiR), ammonium, nitrate and nitrite nitrogen in root-zone soil grown with three-year old apple trees (Malus domestica cv. Starkrimson) during summer and autumn. Results showed that the four treatments decreased nitrification intensity in summer soil, NiR activity in summer-autumn soil and the variation coefficient of nitrification-denitrification intensity and NR in both summer and autumn soil. The treatments increased the denitrification intensity, NR activity, ammonium nitrogen contents in summer-autumn soil and ammonium nitrogen contents in autumn soil. Straw mat treatment increased denitrification intensity and nitrate nitrogen contents in both summer and autumn soil and decreased the activity of NR and NiR in summer soil. The coefficient of variation of nitrification-denitrification intensity and NR activity treated by mulching straw mat was lower than those in the other treatments in both summer and autumn soil. Agricultural carpet increased the NR and NiR activity in summer soil, the nitrate nitrogen contents in summer-autumn soil and the denitrification intensity in autumn soil and decreased denitrification intensity in summer soil. Transparent-plastic film increased the nitrite nitrogen contents in summer soil, the contents of nitrate nitrogen in summer-autumn soil, the nitrification intensity and NiR activity in autumn soil, and decreased nitrate nitrogen contents in summer soil. Horticultural fabric increased denitrification intensity in summer soil, nitrification intensity in summer-autumn and autumn soil and the nitrate nitrogen contents in autumn soil. The four mulching treatments all promoted plant growth. In the four mulching treatments, the new shoot and trunk thickening growth were more under straw mat and horticultural fabric treatments. The four mulching treatments had different effects on nitrate metabolism in summer and autumn soil, but they were able to stabilize the soil nitrate metabolism and transformation. Among the treatments, straw mat had the best stable effect.

Response of water status indicators in apple saplings to drought stress under shelter from rain.

GAO Mu-wang, NIE Pei-xian, SUN Ying, JIANG Yuan-mao, ZHANG Jin-chun, ZHANG Ji-xiang

2016, 27(8):  2459-2466.  doi:10.13287/j.1001-9332.201608.040

Asbtract ( 284 )   PDF (800KB) ( 14 )  

The main tree water status indicators which sensitively responded to drought stress and related to tree water balance were investigated in treatment of progressive decrease of soil water potential under shelter from rain. The results showed that stem maximum daily shrinkage (MDS) and midday stem water potential (Ψ_stem) were most sensitive to drought stress among all the water status indicators. MDS not only significantly responded to reference crop evapotranspiration (ET₀), but also was sensitive to soil drought stress. MDS was significantly positively related to ET₀, and the correlation between relative stem daily maximum shrinkage (MDS_r) and relative soil water potential (Ψ_{r soil}) was highly significant. Moreover, the stems could be measured in succession and recorded automatically. Midday Ψ_stem was also sensitive to soil drought stress, and significantly negatively related to ET₀. The correlation between relative midday stem potential (Ψ_{r stem}) and Ψ_{r soil} was significant. But so far, it is difficult to automatically measure either leaf or stem water potential. Predawn leaf water potential (Ψ_pd), daily stem growth (DG) or stomatal conductance (g_s) also responded to drought stress to some extent under moderate or heavy drought stress, but they were not sensitive.

Effects of the frequency and intensity of nitrogen addition on soil pH, the contents of carbon, nitrogen and phosphorus in temperate steppe in Inner Mongolia, China.

ZHOU Ji-dong, SHI Rong-jiu, ZHAO Feng, HAN Si-qin, ZHANG Ying

2016, 27(8):  2467-2476.  doi:10.13287/j.1001-9332.201608.037

Asbtract ( 332 )   PDF (796KB) ( 20 )  

A four-year simulated nitrogen (N) deposition experiment involving nine N gradients and two N deposition frequencies (N was added either twice yearly or monthly) was conducted in Inner Mongolian grassland, to examine the effects of frequency and intensity of N addition on pH and the contents of carbon, nitrogen and phosphorus in soil. The results indicated that the soil pH and total phosphorus content, regardless of the N addition frequency, gradually decreased with the increase of N addition intensity. By contrast, the contents of soil available nitrogen and available phosphorus showed an increasing trend, while no significant variation in dissolved organic carbon (DOC) content was observed, and the contents of soil total carbon and total nitrogen had no change. Compared with the monthly N addition, the twice-a-year N addition substantially overestimated the effects of N deposition on decreasing the soil pH and increasing the available phosphorus content, but underestimated the effects of N deposition on increasing the soil available nitrogen content, and the significant difference was found in 0-5 cm soil layer.

Effects of water and fertilizer coupling on photosynthetic characteristics of maize leaves in ear position at filling stage in an apple-maize intercropping system in Losses Plateau of west Shanxi Province, China.

GAO Fei, WANG Ruo-shui, XU Hua-sen, WANG Dong-mei, YANG Zong-ru

2016, 27(8):  2477-2490.  doi:10.13287/j.1001-9332.201608.021

Asbtract ( 276 )   PDF (1074KB) ( 18 )  

Taking a typical apple×maize intercropping system in the loess region of Shanxi Pro-vince, China as test object, the current study analyzed the photosynthetic characteristics of maize leaves of ear position at filling stage under different irrigation and fertilization regimes. There were three irrigation levels [low (W₁), 50% field capacity (Fc); medium (W₂), 65% Fc; and high (W₃), 85% Fc], three fertilizer levels {F₁ [N (289 kg·hm^-2) + P₂O₅ (118 kg·hm^-2) + K₂O (118 kg·hm^-2)]; F₂ [N (412.4 kg·hm^-2) + P₂O₅ (168.8 kg·hm^-2) + K₂O (168.8 kg·hm^-2)], F₃ [N (537 kg·hm^-2) + P₂O₅ (219 kg·hm^-2) + K₂O (219 kg·hm^-2)]}, and a control (CK, no irrigation and fertilization throughout the growing season). The nine irrigation and fertilization treatment combinations were W₁F₁, W₂F₁, W₃F₁, W₁F₂, W₂F₂, W₃F₂, W₁F₃, W₂F₃, and W₃F₃, respectively. The results indicated that different water and fertilizer regimes had no significant effect on the variation in diurnal photosynthetic indexes. However, the application of water and fertilizers considerably increased the peak value of net photosynthetic rate (P_n), exten-ded the stomatal opening period, influenced the lowest value of intercellular CO₂ concentration (C_i), and reduced the maximum value of water use efficiency (WUE) during the day. The limiting factors affecting photosynthesis were nonstomatal factors. Stomatal conductance (g_s) and transpiration rate (T_r) were both significantly negatively correlated with the distance from tree line (P<0.01). WUE were significantly positively correlated with the distance from the tree line (P<0.05). g_s decreased by 0.028-0.093 mol·m^-2·s^-1, T_r decreased by 0.56-1.41 mmol·m^-2·s^-1, WUE increased by 0.08-1.00 μmol·mmol^-1, as the average distance from the tree line increased by 1 m. Thus, irrigation and fertilizers significantly increased the mean value of P_n, T_r, and g_s, but decreased the mean value of WUE during the day. The W₃F₁ treatment had the highest mean values of P_n(10.64 μmol·m^-2·s^-1), g_s(0.295 mol·m^-2·s^-1), WUE (3.05 μmol·mmol^-1), but a lower mean value of T_r(4.32 mmol·m^-2·s^-1) compared with the other treatment combinations during the day. When the total irrigation rate was 1300 m³·hm^-2, the total fertilization rate was 525 kg·hm^-2, P_n was at its maximum, and the theoretical maximum value was 10.32 μmol·m^-2·s^-1. Therefore, the W₃F₁ treatment was the irrigation and fertilizer regime that was most likely to improve the photosynthetic efficiency of the apple-maize intercropping system.

Effects of nitrogen application on canopy vertical structure, grain-leaf ratio and economic benefit of winter wheat under drip irrigation.

ZHANG Na, XU Wen-xiu, LI Lan-hai, WU Ni-ping, WU Pei-jie, CHENG Xue-feng

2016, 27(8):  2491-2498.  doi:10.13287/j.1001-9332.201608.028

Asbtract ( 292 )   PDF (717KB) ( 21 )  

To optimize the fertilization rate of winter wheat under drip irrigation in Xinjiang region, a field investigation was carried out to assess effects of nitrogen (N) applications on canopy vertical structure, grain-leaf ratio, yield and economic benefit of winter wheat. Four rates of nitrogen application, 0 kg·hm^-2(N₀), 104 kg·hm^-2(N₁), 173 kg·hm^-2(N₂) and 242 kg·hm^-2(N₃) were set in a randomized block experimental design. Meantime, leaf and stem morphological characters, canopy temperature and humidity in flowering stage, grain-leaf area ratio, yield and yield components, economic benefits of winter wheat were observed under different treatments. The results showed that the leaf length and width at different positions of wheat under the nitrogen fertilization treatments were significantly higher than that without nitrogen fertilization (P<0.05), and plant height ranged from 65.57 to 81.58 cm. With an increasing rate of nitrogen fertilization, both leafarea index and stem diameter presented a trend of first increasing and then decreasing, and reached the maximum under N₂ treatment, which was 5.48 and 0.49 cm, respectively. Diurnal variation of canopy temperature and humidity were “convex” and “concave” shape, followed an order of N₀>N₁>N₂>N₃ in temperature, but reversely in canopy humidity. The duration of high temperature higher than 35 ℃ were shorten 1 hour to 3.5 hours as the nitrogen application level increased, and there was significant difference between N₁ and N₃ on grain-leaf ratio. Yield and economic be-nefit decreased initially and then increased with increasing nitrogen application. Yield and economic benefit of treatment N₂ were 32.8% and 77.7% higher than those of treatment N₀, 12.6% and 5.4% higher than those of treatment N₁, and 5.2% and 4.2% higher than those of treatment N₃, respectively. These results indicated that nitrogen application at about 173 kg·hm^-2 could be recommended as the optimum rate for winter wheat, which had good leaf and plant morphology, appropriate canopy temperature and humidity, high yield and economic efficiency in the experiment area.

Effects of water-controlled irrigation on maize yield and photosynthetic characteristics of ear leaf in Xinjiang Province, China.

WANG Guo-dong, CHEN Yun, LIANG Fei, ZHANG Lei, GUO Bin, ZENG Sheng-he

2016, 27(8):  2499-2506.  doi:10.13287/j.1001-9332.201608.033

Asbtract ( 262 )   PDF (744KB) ( 17 )  

In order to explore the suitable water management patterns for high yield of spring maize under drip irrigation in oasis regions of North Xinjiang, two maize cultivars (Zhengdan 958 and Kenyu 02) were used to study the effect of water-controlled irrigation on the leaf SPAD value at V12-R5 stage, and chlorophyll content, photosyntheticcharacteristics and chlorophyll fluorescence parameters of ear leaf at filling stage in the field. Results showed that the leaf SPAD values peaked under moderate soil moisture treatments during V12-R3 stage. The field capacity of soil moisture above 65% was suitable for the development of corn at R5 stage. The chlorophyll a, b and total chlorophyll contents, carotene, chlorophyll a/b were significantly decreased when soil moisture was less than 75%, however the above parameters had no significant difference when soil moisture was more than 85%. The net photosynthetic rate (P_n), transpiration rate (T_r) and stomata conductance (g_s) of ear leaf were significantly decreased in filling stages when soil moisture was less than 75%, but the intercellular CO₂ concentration (C_i) was significantly increased. The reduction of g_s was not observed when the soil moisture was more than 85% of field capacities. Meanwhile, the variable fluorescence to maximal fluorescence (F_v/F_m), potential activities of PSII (F_v/F_o), PSⅡ actual photochemical efficiency (Φ_PSⅡ), photochemical quenching (q_P) and electron transport rate (rETR) decreased significantly under both higher and lower soil moisture treatments. However, the F_o/F_m and non-photochemical quenching (NPQ) significantly increased at the same time. The path analysis showed that the decrease of P_n resulted from the decrease of F_v/F_o and rETR, which finally resulted in decreased production of spring maize. Therefore, the optimal field moistures for these two spring maize cultivars were >60%, >70%, >75%, >80% and >65% for the growing stages V6, V12, R1, R3 and R5, respectively, to obtain a high yield in the oasis region.

Effects of alternate subsurface drip irrigation on yield and water use efficiency of spring maize.

HUANG Peng-fei, YIN Guang-hua, GU Jian, LIU Zuo-xin, GUO Jin-lu

2016, 27(8):  2507-2512.  doi:10.13287/j.1001-9332.201608.032

Asbtract ( 305 )   PDF (476KB) ( 18 )  

The experiment was conducted using automatic rain shelter to study the effect of precisely controlled water quota of alternate subsurface drip irrigation (ASDI) on spring maize yield and water use efficiency (WUE). The results showed that jointing to heading stage and heading to hilling stage were the key stages of water requirement for spring maize under ASDI. In particular, both the water consumption percentage and diurnal water consumption in these two stages were higher than in other stages and were more sensitive to water deficit stress. The water demand in these two stages should be prioritized if irrigation was limited. Maize yield generally increased with the increasing irrigation quota. When the irrigation quota below 2764.5 m³·hm^-2, the yield increased rapidly with the increasing irrigation quota. The yield increase then slowed down after the irrigation quota reached 2764.5 m³·hm^-2. The maximum of maize yield of 12109.0 kg·hm^-2 was obtained at the irrigation quota of 3357.1 m³·hm^-2. Compared to fixed subsurface drip irrigation (FSDI), under the same irrigation quota, the yield, WUE and irrigation water use efficiency (IWUE) of spring maize in ASDI treatment were improved by 5.4%, 1.4% and 5.6%, respectively. Compared to FSDI, the maize yield in ASDI decreased by 1.8%, but its WUE and IWUE increased by 11.0% and 22.7% when the irrigation quota decreased by 20%. The optimal irrigation quota of ASDI for spring maize in the study area was1600.4-3357.1 m³·hm^-2 by taking into account of yield and WUE.

Response of grain filling characteristics of maize to sowing date.

XU Tian-jun, LYU Tian-fang, ZHAO Jiu-ran, WANG Rong-huan, CHEN Chuan-yong, LIU Yue-e, LIU Xiu-zhi, WANG Yuan-dong

2016, 27(8):  2513-2519.  doi:10.13287/j.1001-9332.201608.027

Asbtract ( 328 )   PDF (655KB) ( 18 )  

To study the effect of different sowing dates on the process of grain filling characteristics, Jingke 528 (JK528) and Zhengdan 958 (ZD958) were used in the field experiment with two sowing dates (10th April and 14th May). The results showed that the 100-grain dry mass and yield of JK528 and ZD958 with the early spring sowing were significantly higher than that with the spring sowing date, which increased by 6.8% and 10.1%, 17.8% and 9.2%, respectively. The maximum grain filling rate (G_max) and the average grain filling rate (G_ave) were higher with the early spring sowing than that with the spring sowing date, while the active grain filling period (P) showed an opposite trend. The 100-grain mass and yield of JK528 were significantly improved by 7.4 g and 1189.6 kg·hm^-2 compared to ZD958, with the increase of 21.6% and 10.8%, respectively. The P of ZD958 was higher than that of JK528, while W_max, G_max, G_ave and T_max of JK528 were higher than that of ZD958. The average grain filling rate of JK528 during early and mid grain filling stages was higher than that of late grain filling stages, which was also higher than that of ZD958 at the same sowing date. Furthermore, correlation analysis revealed that the mean temperature and the accumulated temperature were significantly positively correlated with the grain dry matter accumulation. Therefore, the full use of hot-ray resources and the increase of the mean grain-filling rate could improve maize grain yield. The higher grain filling rate during early and mid grain filling stages in JK528 could compensate for the short active grain filling period, leading to higher yields under different sowing dates.

Effects of different microbial agents on substrate enzyme activities and tomato yield and quality.

HOU Le-mei, MENG Rui-qing, NIE Lan-chun, QI Ying-bin

2016, 27(8):  2520-2526.  doi:10.13287/j.1001-9332.201608.015

Asbtract ( 302 )   PDF (418KB) ( 19 )  

Chicken manure substrate (fermented chicken manure:fermented corn stalk:river sand=3:4:3) and cattle manure substrate (fermented cattle manure:fermented corn stalk:river sand=3:4:3) were used to study the effects of microbial agents (‘Difulai’, enzyme microorganism, EM bacteria, Bacillus subtilis, and agricultural microbial agent) on substrate enzyme activities and tomato yield and quality. The results showed that the activities of urease, invertase and alkaline phosphatase in both two substrates all significantly increased at 40 d and 60 d after microbial agent addition. The growth, yield and vitamin C content of tomato were higher than those of control. Among the microbial agents, ‘Difulai’ showed the best effect in both two substrates. Plant yield increased by 14.7% and 40.0%, tomato vitamin C content increased by 22.2% and 39.7% respectively in chicken manure and cattle manure substrate with ‘Difulai’ addition. Yield and vitamin C content of tomato plant in chicken manure substrate without microbial agent addition were higher than that in cattle manure substrate, while there was no significant difference in two substrates with ‘Difulai’ addition.

Effects of different NO₃^--N/NH₄⁺-N ratios on cucumber seedlings growth, nitrogen absorption and metabolism under suboptimal temperature and light intensity

ZHANG Xiao-cui, LIU Yu-mei, BAI Long-qiang, HE Chao-xing, YU Xian-chang, LI Yan-su

2016, 27(8):  2527-2534.  doi:10.13287/j.1001-9332.201608.029

Asbtract ( 385 )   PDF (635KB) ( 29 )  

Cucumber (cv. Zhongnong 26) was used as material, the effects of NO₃^--N/NH₄⁺-N ratios on growth and physiological characteristics of cucumber seedlings under suboptimal temperature and light intensity (18 ℃/10 ℃,180 ± 20 μmol·m^-2·s^-1) were studied. Total nitrogen in the nutrient solution was equal and three NO₃^--N/NH₄⁺-N ratios, 26:2, 21:7 and 14:14, were applied as treatments. The results showed that cucumber treated by NO₃^--N/NH₄⁺-N=21:7 had the longest total root length, the biggest root volume and root surface area, and the maximum number of root tips. H⁺-ATPase activity and relative expression of genes encoding nitrate transporter (NRT) and ammonium transporter (AMT) in cucumber roots were increased significantly by the treatment of NO₃^--N/NH₄⁺-N=21:7. In addition, nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) in cucumber leaves under the treatment of NO₃^--N/NH₄⁺-N=21:7 were higher. As a result, the nitrogen content and biomass of cucumber were significantly increased. Compared with the plants under the treatment of NO₃^--N/NH₄⁺-N=26:2 or 14:14, cucumber seedlings under the treatment of NO₃^--N/NH₄⁺-N=21:7 had the highest biomass and total dry mass (DM) which were increased by 14.0% and 19.3% respectively under suboptimal temperature and light intensity. In conclusion, under suboptimal environmental conditions, NO₃^- -N/NH₄⁺-N ratio could be adjusted to increase nitrogen absorption and metabolism of cucumber and alleviate the de-trimental effects caused by suboptimal conditions and promoted the cucumber growth.

Effects of purified humic acid on growth and nutrient absorption of cucumber (Cucumis sativus)seedlings under low nitrogen stress.

GU Duan-yin, WANG Xiu-feng, YANG Feng-juan, JIAO Juan, WEI Min, SHI Qing-hua

2016, 27(8):  2535-2542.  doi:10.13287/j.1001-9332.201608.016

Asbtract ( 333 )   PDF (601KB) ( 23 )  

Taking ‘Xintaimici’ and ‘Jinyou 1’ as experimental cucumber cultivars, this paper studied the effects of watering purified humic acid (PHA) at different levels (0, 50, 100, 150, 200 mg·L^-1) on growth and nutrient absorption of cucumber seedlings under low nitrogen stress (1 mmol·L^-1 NO₃^-) in sand culture pots. The results showed that, under low N condition, PHA could significantly increase the total root length, root surface area, root tip number and root volume of cucumber seedlings, and promote plant height, stem diameter and leaf area. Proline and soluble sugar contents in cucumber leaves were significantly increased by PHA. The absorption of N, P, K, Ca, Mg, Fe in cucumber seedlings was promoted. According to the response of the two cucumber cultivars to PHA under low N stress, some traits of two cultivars showed different sensitivity to PHA level. The comprehensive analysis of the above results inferred that the PHA level from 100 mg·L^-1 to 150 mg·L^-1 could significantly enhance the growth and nutrient absorption of cucumber seedlings.

Light-use efficiency of tomato seedling leaves at different CO₂ concentrations.

YE Zi-piao, KANG Hua-jing, YANG Xiao-long

2016, 27(8):  2543-2550.  doi:10.13287/j.1001-9332.201608.035

Asbtract ( 340 )   PDF (886KB) ( 31 )  

Light-use efficiency (LUE) is an important parameter to assess light energy absorption of leaf. Especially, it is a key factor to affect production and quality of ecosystem. A model of LUE was developed based on a mechanistic model of light-response of photosynthesis. The maximum LUE (LUE_max) and corresponding saturation irradiance (I_L-sat) were deduced according to the LUE mo-del. At CO₂ concentrations of 350, 450, 550 and 650 μmol·mol^-1, the light-response curves of LUE of tomato seedling leaves were simulated. The results showed that the model of LUE described well the response curves of light use efficiency of tomato seedling leaves at four CO₂ concentrations. LUE of tomato seedling leaves reached the maximum value at photosynthetically active radiation between 70-90 μmol·m^-2·s^-1. There were no difference of LUE_max and I_L-sat at 550 and 650 μmol·mol^-1. Regarding this phenomenon, it was hypothesized that the photosynthetic functions of tomato seedling leaves had acclimated to the low irradiance in greenhouse so that the intrinsic cha-racteristic of light-harvesting pigments such as the effective light absorption cross-section of light-harvesting pigments and ratio of pigment molecules in the excited state to ground state had hardly changed at high CO₂ concentrations.

Soil respiration rates and its affecting factors in winter wheat land in the Weihe Plain, Northwest China.

ZHANG Xiao-long, SHEN Bing, QUAN Quan, DONG Liang, TIAN Kai-di

2016, 27(8):  2551-2560.  doi:10.13287/j.1001-9332.201608.024

Asbtract ( 358 )   PDF (910KB) ( 23 )  

Based on measurement on winter wheat soil respiration (SR), environmental and biotic factors from 2013 to 2014 in semi-humid and prone-to-drought area of Weihe Plain, this paper analyzed the characteristics of diurnal and seasonal variation of SR and influences of temperature (T), soil water content (W), gross primary productivity (GPP) and leaf area index (LAI). The results showed that the SR diurnal variation appeared as a single-peak curve ranging between 1.5 and 6.94 μmol CO₂·m^-2·s^-1, with the peak presented during 12:00-14:00. Temperature was the driving factor for the SR diurnal variation, and land surface temperature (T_s) could explain 80.9% of the temporal variation for SR. The corresponding relationship between SR and temperature showed a clockwise nearly elliptic curve. From seedling stage to winter, the SR rate of wheat showed a descending trend, and stayed at a relatively low level until regreening stage. Then the rate of SR increased rapidly and reached peak in heading stage and filling stage, but there was a descending trend in mature stage. The SR values in growth period were between 0.65 and 4.85 μmol CO₂·m^-2·s^-1. T, W, GPP and LAI were positively related to SR (P<0.01). Soil temperature and soil water content were the dominant factors affecting the SR seasonal variation, and they could explain 82.6% of its variation by a compound model SR=e^{(a+bT_{5 cm}}+cW10 cm+dW_{10 cm²}), which was much better than monovariant model (below 65.7%). Based on the compound model results, the average rate of wheat SR during growth period in 2013-2014 was 1.67 μmol CO₂·m^-2·s^-1.

Evolution of maize climate productivity and its response to climate change in Heilongjiang Province, China.

LI Xiu-fen, ZHAO Hui-ying, ZHU Hai-xia, WANG Ping, WANG Qiu-jing, WANG Ming, LI Yu-guang

2016, 27(8):  2561-2570.  doi:10.13287/j.1001-9332.201608.011

Asbtract ( 297 )   PDF (1507KB) ( 18 )  

Under the background of climate change, revealing the change trend and spatial diffe-rence of maize climate productivity in-depth and understanding the regularity of maize climatic resources utilization can provide scientific basis for the macro-decision of agricultural production in Heilongjiang Province. Based on the 1981-2014 meteorological data of 72 weather stations and the corresponding maize yield data in Heilongjiang Province, by the methods of step by step revisal, spatial interpolation and linear trend analysis, this paper studied the photosynthetic productivity (PP), light-temperature productivity (LTP), and climatic productivity (CP) of spring maize, and their temporal and spatial variation characteristics, main influencing factors and light energy utilization efficiency, and evaluated the maize climate productivities under different climate scenarios in the future. The results showed that during the study period, the mean PP, LTP and CP in Heilongjiang Province were 26558, 19953, 18742 kg·hm^-2, respectively. Maize PP, LTP and CP were high in plains and low in mountains, and gradually decreased from southwest to northeast. PP, LTP and CP presented significantly increasing trends, and the increase rates were 378, 723 and 560 kg·hm^-2·(10 a)^-1, respectively. The increase of radiation and temperature had positive effect on maize production in Heilongjiang Province. The potential productivity of maize presented significant response to climate change. The decrease of solar radiation led to the decline of PP in western Songnen Plain, but the increased temperature compensated the negative effect of solar radiation, so the downward trend of LTP was slowed. The response to climate warming was particularly evident in North and East, and LTP was significantly increased, which was sensitive to the change of precipitation in southwest of Songnen Plain and part of Sanjiang Plain. The average ratio of maize actual yield to its climate productivity was only 24.1%, there was still 75.9% to be developed. In the future, the warm and wet climate would benefit the improvement of maize climate productivity, while the cold and dry climate would make an adverse impact.

Rice area change in Northeast China and its correlation with climate change.

CHEN Hao, LI Zheng-guo, TANG Peng-qin, HU Ya-nan, TAN Jie-yang, LIU Zhen-huan, YOU Liang-zhi, YANG Peng

2016, 27(8):  2571-2579.  doi:10.13287/j.1001-9332.201608.036

Asbtract ( 473 )   PDF (2788KB) ( 43 )  

Based on the time-series map of rice area, a spatial production allocation model (SPAM) which has been applied for mapping the global level crop allocation datasets was deve-loped to simulate the spatio-temporal dynamics of rice area in Northeast China during 1980-2010 within 5′×5′ grid cells. The spatio-temporal variations of rice area with temperature and precipita-tion during past 30 years were explored. The results indicated that the rice area expanded significantly northwards to46° N before 2000. After that, the increased sown area mainly occurred in the northern parts of Northeast China. Meanwhile, rice area also expanded eastwards to 131° E and toward the higher elevation regions (above 200 m). Due to a northward movement of accumulated temperature belts, the new rice area mainly appeared in the regions with an annual accumulated temperature (AAT) between 2800 and 3400 ℃·d. The trend of precipitation during the study period increased before 2000 and decreased afterwards. The increased rice area was found mainly in the regions with precipitation range from 300 mm to 600 mm.

Simulation on PM_2.5 detention service of green space in Haidian District, Beijing, China.

LIU Wen-ping, YU Zhen-rong

2016, 27(8):  2580-2586.  doi:10.13287/j.1001-9332.201608.001

Asbtract ( 313 )   PDF (3657KB) ( 20 )  

Green space plays an important role in reducing PM_2.5, since it can efficiently absorb suspended particles in the air. A quantificational method of dust detention service of green space was proposed in this study, based on the mechanism of PM_2.5 reduction by plant. Daily, summer, winter and whole year cumulative dust amounts reduced by green space with different landscape types of Haidian District, Beijing, were quantified. The results showed that both of dust reduction frequency and daily cumulative dust amount in winter were considerably lower than those in summer. Mountain woodlands in the west of Haidian District provided the highest average PM_2.5 reduction service, and the fragmented agricultural and forest landscapes in the northern plains provided the highest total dust detention service, while the southern area had the lowest dust detention service except for several parks. PM_2.5 detention service model was very useful to quickly quantify how much dust could be reduced by green space and where were these services, which was very important for the development of urban green space and improvement of air quality.

Simulation on area threshold of urban building land based on water environmental response in watersheds.

HE Zhi-chao, HUANG Shuo, GUO Qing-hai, XIAO Li-shan, YANG De-wei, WANG Ying, YANG Yi-fu

2016, 27(8):  2587-2597.  doi:10.13287/j.1001-9332.201608.017

Asbtract ( 362 )   PDF (4458KB) ( 21 )  

Urban sprawl has impacted increasingly on water environment quality in watersheds. Based on water environmental response, the simulation and prediction of expanding threshold of urban building land could provide an alternative reference for urban construction planning. Taking three watersheds (i.e., Yundang Lake at complete urbanization phase, Maluan Bay at peri-urbanization phase and Xinglin Bay at early urbanization phase) with 2009-2012 observation data as example, we calculated the upper limit of TN and TP capacity in three watersheds and identified the threshold value of urban building land in watersheds using the regional nutrient management (ReNuMa) model, and also predicted the water environmental effects associated with the changes of urban landscape pattern. Results indicated that the upper limit value of TN was 12900, 42800 and 43120 kg, while that of TP was 340, 420 and 450 kg for Yundang, Maluan and Xinglin watershed, respectively. In reality, the environment capacity of pollutants in Yundang Lake was not yet satura-ted, and annual pollutant loads in Maluan Bay and Xinglin Bay were close to the upper limit. How-ever, an obvious upward trend of annual TN and TP loads was observed in Xinglin Bay. The annual pollutant load was not beyond the annual upper limit in three watersheds under Scenario 1, while performed oppositely under Scenario 3. Under Scenario 2, the annual pollutant load in Yundang Lake was under-saturation, and the TN and TP in Maluan Bay were over their limits. The area thresholds of urban building land were 1320, 5600 and 4750 hm² in Yundang Lake, Maluan Bay and Xinglin Bay, respectively. This study could benefit the regulation on urban landscape planning.

Landscape pattern change of ethnic townships under the background of urbanization: Case of Aerla Town in Molidawa Daur Autonomous Banner, Inner Mongolia, China.

YANG Jin-yao, HUANG Lu, YAN Li-jiao, HUO Si-gao

2016, 27(8):  2598-2604.  doi:10.13287/j.1001-9332.201608.025

Asbtract ( 374 )   PDF (850KB) ( 16 )  

With the stable development of new countryside construction and new-type urbanization, the changing of the landscape pattern in countryside attracts more attention, especially in the ethnic townships which are hardly accessible. To explore the development of these areas, it is crucial to understand the spatial and temporal variation of the landscape pattern. In this paper, the landscape pattern change was analyzed at both patch type level and landscape level based on the landscape ecology theory. The land use data (format: vector) got from Aerla Town (a typical Daur ethnic township in Inner Mongolia) for the duration from 2008 to 2013 was studied by ArcGIS platform and Fragstats. For the type level, the grassland, farmland, and forest turned into building land gra-dually. Regarding the landscape level, the landscape diversity index and landscape connectivity index were relatively low, the heterogeneity index and the landscape fragmentation were relatively high. With considering the correlation analysis and grey correlation of the above indexes as well as the social and economic development in Aerla Town, the results indicated that population change and GDP growth were the main driving forces of landscape pattern change. Finally, the driving forces which resulted in the variation of landscape pattern with the incorporation of the economic, cultural, policy, and natural effects were discussed. The research could provide basic information and theoretical foundation for the development of minority areas in Northeast China.

Delimitation of urban growth boundary based on ecological suitability and risk control: A case of Taibai Lake New District in Jining City, Shandong, China.

LIU Yan-xu, PENG Jian, SUN Mao-long, YANG Yang

2016, 27(8):  2605-2613.  doi:10.13287/j.1001-9332.201608.004

Asbtract ( 349 )   PDF (6296KB) ( 32 )  

Urban growth boundary, with full consideration of regional ecological constraints, can effectively control the unordered urban sprawl. Thus, urban growth boundary is a significant planning concept integrating regional ecological protection and urban construction. Finding the preferential position for urban construction, as well as controlling the ecological risk, has always been the core content of urban growth boundary delimitation. This study selected Taibai Lake New District in Jining City as a case area, and analyzed the scenario of ecological suitability by ordered weighted ave-raging algorithm. Surface temperature retrieval and rain flooding simulation were used to identify the spatial ecological risk. In the result of ecological suitability, the suitable construction zone accounted for 25.3% of the total area, the unsuitable construction zone accounted for 20.4%, and the other area was in the limit construction zone. Excluding the ecological risk control region, the flexible urban growth boundary covered 2975 hm² in near term, and covered 6754 hm² in long term. The final inflexible urban growth boundary covered 9405 hm². As a new method, the scenario algorithms of ordered weighted averaging and ecological risk modeling could provide effective support in urban growth boundary identification.

Coupling between ecological vulnerability and economic poverty in contiguous destitute areas, China: Empirical analysis of 714 poverty-stricken counties.

CAO Shi-song, WANG Yan-hui, DUAN Fu-zhou, ZHAO Wen-ji, WANG Zhi-heng, FANG Na

2016, 27(8):  2614-2622.  doi:10.13287/j.1001-9332.201608.020

Asbtract ( 356 )   PDF (1163KB) ( 33 )  

Maintaining the coordinated correlation between ecological environment and economic development is one of the important strategies in the new stage of poverty alleviation and development. Taking 714 poverty-stricken counties in contiguous destitute areas as study areas, this paper designed the ecological vulnerability evaluation indicator system based on the ecological sensitivity-resilience-pressure (SRP) conceptual model, as well as the comprehensive poverty evaluation indicators from the perspective of socioeconomic development, so as to build the coupling model to reveal the coupling between ecological vulnerability and economic poverty. The results showed that Hu-Line could act as a feasible partition label to depict the spatial distribution patterns of ecological vulnerability, economic poverty, as well as their coupling degree in contiguous destitute areas, which should be fully taken into consideration the influence of Hu-Line on the east-west pattern classification of national poverty reduction. In addition, there existed a symbiotic positive correlation between ecological vulnerability and economic poverty, therefore, the strategic significance of ecological and environment protection in poverty-stricken areas should be specifically emphasized to reduce economic poverty by synchronously protecting the ecological environment. Approximately half of the counties involved in the study area were in the coordinated type of recession disorders, where the ecological environment quality and the economic development could not be synchronized.

Ecological functions of E-β-farnesene on aphids and their natural enemies in potato field.

LIU Ying-jie, CHI Bao-jie, LIN Fang-jing, MAIGRET Olivier, ZHENG Lu-fei, LIU Yong

2016, 27(8):  2623-2628.  doi:10.13287/j.1001-9332.201608.005

Asbtract ( 412 )   PDF (517KB) ( 24 )  

As a most common component of aphid alarm pheromone, E-β-farnesene (EβF) could not only dispel aphids, but also modify some behavioral responses of their natural enemies. In order to investigate the ecological function of EβF, its influence on the population dynamics of Myzus persicae (Sulzer), Aphis gossypii (Glover), Macrosiphum euphorbiaein (Thomas) and their natural enemies was studied in potato fields. The results showed that there were significantly lower aphid abundance (2012, 2013), higher ladybird beetle abundance (2012, 2013), and higher mummified aphid abundance (2012) on potato plants in EβF treated plots (100 μL per week). The numbers of aphids at the distances of 1 m and 5 m from EβF releaser were significantly lower compared to 10 m in 2012, and the aphid number was significantly lower at the distance of 1 m compared to 5 m and 10 m in 2013. Moreover, significantly higher parasitoid and hoverfly numbers in 2012 and higher numbers of ladybird beetles in 2013 were observed in yellow traps in EβF treated plots. The results suggested that EβF could suppress aphid population growth within a certain distance in potato fields.

Sublethal effects of fenpropathrin and avermectin on Panonychus citri (Acari: Tereanychidae).

HE Heng-guo, YAN Xiang-hui, WANG Jin-jun, ZHAO Zhi-mo

2016, 27(8):  2629-2635.  doi:10.13287/j.1001-9332.201608.019

Asbtract ( 432 )   PDF (579KB) ( 24 )  

A leaf disc bioassay was employed to examine the effects of fenpropathrin and avermectin with a sublethal concentration of LC₂₀ on the development and reproduction of F₀, F₁ and F₂ generations by means of life tables. The results showed that after the treatment of fenpropathrin at the sublethal concentration, the number of eggs laid per female significantly increased in F₀ generation, the pre-oviposition duration was significantly shortened and the female ratio of offspring significantly increased both in F₁ and F₂ generations. The intrinsic rate of increase (r_m) and finite rate of increase (λ) values all increased, and the generation time (T) and population doubling time (Dt) were shortened in F₁ and F₂ generations, with significant difference observed between F₂ generations and the control. After exposure to avermectin, the number of eggs laid per female significantly decreased in F₀ generation, and progeny (F₁ and F₂) also produced fewer eggs than the control, while the female ratio of offspring increased both in F₁ and F₂ generations and the pre-oviposition period was significantly shortened. The r_m and λ values all increased, and the T and Dt were shortened in F₁ and F₂ generations. Such effects were more obvious on the F₂ generation than the F₁ generation. Generally, the effects of fenpropathrin and avermectin with a sublethal concentration of LC₂₀ were not exactly the same on P. citri. Fenpropathrin could promote the development of the contemporary population, while avermectin had certain inhibition on the contemporary population, but both played a certain role in facilitating the development of future populations, which was of significance in developing integrated pest management strategies.

Effects of Flaveria bidentis invasion on the diversity of functional bacteria in rhizosphere soil.

SONG Zhen, JI Qiao-feng, FU Wei-dong, ZHANG Rui-hai, ZHANG Ting, YAN Jing, ZHANG Guo-liang

2016, 27(8):  2636-2644.  doi:10.13287/j.1001-9332.201608.013

Asbtract ( 308 )   PDF (856KB) ( 21 )  

Flaveria bidentis is an invasive plant found in large areas of northern China. This study conducted a separation and screening of the main functional bacteria in the soil of F. bidentis and investigated the change in the community structure. A variety of functional microbes were isolated using selective media and rep-PCR clustering, and a diversity analysis was carried out. In addition, the dominant populations of various functional bacteria were identified using 16S rRNA sequence alignment. The results showed that F. bidentis increased the contents of the major available nutrients in the soil, and the levels of azotobacteria, organic phosphorus bacteria, inorganic phosphorus bacteria, and silicate bacteria in the soil of F. bidentis were significantly higher than those of the native plant Tagetes erecta and the control. rep-PCR analysis indicated that the structure of the four functional bacterial microfloras in the soil of F. bidentis was significantly different from those of the native plant and control. The diversity analysis demonstrated that the diversity of functional microorganisms in the soil of F. bidentis was richer, the community structure was more complex, the predominant microflora comprised a greater proportion of the total population, and the ecological diversity was higher. This was further evidenced by identification of the main functional isolates from the three soil samples. Our findings indicated a mechanism of invasion by F. bidentis.

Effects of re-vegetation on soil microbial functional diversity in purple soils at different re-vegetation stages on sloping-land in Hengyang, Hunan Province, China.

WEN Dong-xin, YANG Ning, YANG Man-yuan

2016, 27(8):  2645-2654.  doi:10.13287/j.1001-9332.201608.009

Asbtract ( 332 )   PDF (598KB) ( 24 )  

The aim of the study was to explore the effects of re-vegetation on soil microbial functio-nal diversity in purple soils at different re-vegetation stages on sloping-land in Hengyang, Hunan Province, China. By using the spatial series to replace time series, four typical sampling plots, grass (Setaria viridi, GS), frutex and grass (Lagerstroemia indica-Setaria viridi, FG), frutex (Vitex negundo var. cannabifolia+Robinia pseudoacacia, FX), as well as arbor and frutex (Liquidamdar formosana+Melia azedarach-Vitex negundo var. cannabifolia, AF) community were selected to study the soil microbial functional diversity by using the Biolog-ECO micro-plate technique. The four communities in purple soils on sloping-land were similar and denoted four different re-vegetation stages. The results showed that the soil microbial metabolic activity increased after re-vegetation significantly, and the average well color development (AWCD) which represented soil microbial activity and functional diversity followed the order of AF community＞FX community＞FG community＞GS community at different re-vegetation stages, and followed the order of 0-10 cm ＞10-20 cm in different soil layers. Principal component analysis (PCA) identified that FG and FX community had similar C sources utilization mode and metabolic function, and GS and AF community were diffe-rent. The carbohydrates, amino acids, intermediate metabolites, and secondary metabolites were the main carbon sources separating the two principal component factors. The Shannon species richness index (H), Shannon evenness index (E), Simpson dominance index (D), McIntosh index (U) at four re-vegetation stages were the highest in AF community, the second in FG and FX community, and the lowest in GS community. The results of correlation analysis indicated that the content of soil water content (SWC), soil total organic carbon (STOC), total nitrogen (TN), total phospho-rus (TP) and available phosphorus (AP) had important influence on the soil microbial metabolic function and functional diversity indices. There existed significant correlation between the activities of urease (URE), alk-phosphatase (APE), invertase (INV), catalase (CAT) and the soil microbial metabolic function and functional diversity indices. All the results indicated that re-vegetation could enhance the soil microbial metabolic function, which was beneficial to the reproduction of soil micro-organisms, thereby promoting an increase of soil carbon source utilization intensity.

Effects of Pseudomonas syringae pv. tabaci infection on tobacco photosynthetic apparatus under light or dark conditions.

CHENG Dan-dan, SUN Jian-ping, CHAI Yuan, ZHU Yi-yong, ZHAO Min, SUN Guang-yu, SUN Xing-bin

2016, 27(8):  2655-2662.  doi:10.13287/j.1001-9332.201608.006

Asbtract ( 444 )   PDF (983KB) ( 179 )  

Pseudomonas syringae pv. tabaci (Pst) is a hemi-biotrophic bacterial pathogen that causes the formation of brown spots named wildfire disease. Pst has received considerable attention in recent years. However, most of the studies focused on the tolerance and defense mechanisms of the host and non-host plants against Pst infection and a toxin originally described as being from Pst named tabtoxin, little information is available on the photosynthetic performance of tobacco leaves after Pst infection. Exploring the effects of Pst on the photosystem Ⅱ (PSⅡ) will not only help in clarifying tobacco-Pst interaction mechanisms, but also deepen the understanding of bacterial pathogen disease from a physiological perspective. By analyzing chlorophyll a fluorescence transient, performing western blot of thylakoid membrane and measuring the content of reactive oxygen species (ROS) and total chlorophyll, the effects of Pst on PSⅡ in tobacco were studied under light (200 μmol·m^-2·s^-1) or dark conditions. The results showed that chlorophyll content significantly decreased and significant chlorosis of the infiltrated zone was observed compared to the untreated ones, and tobacco leaves exhibited a visible and overt wildfire symptom at 3 days post Pst infection (dpi) under light and dark conditions. The H₂O₂ content increased at 3 dpi compared to untreated ones in tobacco leaves under light and dark conditions, and was much higher under light than dark condition. Besides, markedly increase of the normalized relative variable fluorescence at the K step (W_K) and the relative variable fluorescence at the J step (V_J), significant decrease of maximal quantum yield of PSⅡ (F_v/F_m) and density of Q_A^- reducing PSⅡ reaction centers per cross section (RC/CSm) were observed in tobacco leaves after Pst infection at 3 dpi under light and dark conditions. Moreover, inhibition of the K and J steps was more pronounced in the dark, as indicated by the greater increase of W_K and V_J under darkness compared with the light conditions during Pst inoculation. Dramatic (net) degradation of D1 protein and PsaO, the core protein of PSⅡ reaction center and oxygen evolving complex (OEC) respectively, at 3 dpi after Pst infection was observed in tobacco leaves under both light or dark conditions, and the decline was more exacerbated under dark than light condition. The results indicated that the electron transport from Q_A to Q_B of photosynthesis electron transport chain was severely blocked, OEC was damaged on both the donor and acceptor sides, and the reaction center of PSⅡ was severely damaged by Pst infection in tobacco lea-ves under either light or dark condition. Photoinhibition and photoinhibition-like damage of PSⅡ was observed after Pst infection, and the damage to PSⅡ under dark condition was much more severe than under light condition in tobacco leaves.

Effects of manure application on the diversity of corn root endophytic bacterial communities at seedling stage in eroded Mollisols.

YU Jiang, YU Zhen-hua, IKENAGA Makoto, SAKAI Masao, LIU Xiao-bing, WANG Guang-hua

2016, 27(8):  2663-2669.  doi:10.13287/j.1001-9332.201608.012

Asbtract ( 378 )   PDF (623KB) ( 21 )  

In order to investigate the change of root endophytic bacterial communities under soil erosion condition, and to evaluate the response of root endophytic bacteria to manure fertilizer, we adopted the LNA-PCR clamping and 454 bar-coded pyrosequencing methods to study the corn root endophytic bacterial communities under 30 cm topsoil erosion and manure fertilization conditions. No topsoil removing (0 cm) and only chemical fertilizer treatment were used as control. A total of 37820 valid sequences of 16S rDNA were obtained, mainly distributed in 4 phyla, 35 classes, 214 genera and 782 OTUs. The dominant phyla were Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes, but their proportions varied in different samples. The diversity of corn root endophytic bacteria decreased in soil erosion condition. In the topsoil removing soil and no erosion soil, the diversity of corn root endophytic bacterial communities increased by manure application, and the effect was more obvious in the topsoil removing soil.

Total nitrogen and total phosphorus thresholds for epilithic diatom assemblages in inflow tributaries of the Three Gorges Reservoir, China.

TANG Ting, REN Ze, TANG Tao, CAI Qing-hua

2016, 27(8):  2670-2678.  doi:10.13287/j.1001-9332.201608.010

Asbtract ( 346 )   PDF (851KB) ( 38 )  

To study the relationships between in-stream total nitrogen (TN) and phosphorus (TP) loads and responses of epilithic algal metrics, nonparametric change-point analysis (nCPA) and thresholds indicator taxa analysis (TITAN) were used to detect possible TN and TP thresholds for algal chlorophyll a, diatom richness, Shannon diversity index, and diatom community composition for tributary rivers of the Three Gorges Reservoir (TGR). We found that nCPA simulated similar TP thresholds for all the four algal metrics (-0.03 mg·L^-1), with similar TN thresholds (-0.8 mg·L^-1) for all metrics but community composition. In contrast, TITAN provided specific nutrient thresholds for both sensitive and tolerant taxa within the whole community, and the threshold ranges covered thresholds for the other metrics. Additionally, nine (one sensitive and eight tolerant taxa) and ten indicator taxa (five sensitive and five tolerant taxa) for TN and TP were detected by TITAN, respectively. Therefore, we used the results of TITAN to define nutrient thresholds for the study rivers. That is, when in-stream TN concentration exceeded 0.382 mg·L^-1 or TP concentration exceeded 0.016 mg·L^-1(i.e. negative response threshold), sensitive taxa within river epilithic diatom assemblages would respond with decrease in density. When TN exceeded 1.298 mg·L^-1 or TP exceeded 0.065 mg·L^-1(i.e. positive response threshold), even tolerant taxa would be influenced and the whole assemblage would be changed significantly. Based on such criteria, we found that 87% sites had TN concentrations higher than the negative response threshold, with 22% sites being higher than the TN positive response threshold. As for TP, 94% and 14% sites exceeded the negative and positive response threshold, respectively. Our findings suggest that although most of the inflow tributaries of Three Gorges Reservoir were disturbed by human disturbance, yet the disturbance was not so extensive. Our findings provided significant information for managing river ecosystems of the TGR region.

Spatial distribution characteristics of carbon, nitrogen and phosphorous and pollution status evaluation of sediments in the Haihe River Basin, China.

CHENG Xian, SUN Ran-hao, KONG Pei-ru, CHEN Li-ding

2016, 27(8):  2679-2686.  doi:10.13287/j.1001-9332.201608.008

Asbtract ( 364 )   PDF (1285KB) ( 33 )  

Studying the distribution of carbon, nitrogen and phosphorus of sediments on a whole-watershed scale is important to the research and management of water resources in the Haihe River Basin (HRB). In this study, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) of 163 samples were investigated in the HRB. Based on these data, the pollution le-vels of sediments were assessed by using different quantitative indices. The results showed that the concentrations of TOC, TN, and TP in the HRB were heterogeneous at different locations. A decreasing trend of concentrations was found from downstream plains (e.g., the Beisihe River and the Heilonggang River) to mountain areas (e.g., the Yongdinghe River, the Beisanhe River, and the Luanhe River). In addition, the concentration of TOC in river sediments was higher than that of reservoir sediments. The statistical analyses showed that TN was significantly (P<0.01) correlated to TOC and TP, with a correlation coefficient of 0.704 and 0.250, respectively. The pollution level based on organic indices was classified as the clean level in the HRB. However, the areas with a relatively high pollution level were still found in some spots, such as the Beisihe River, and the Heilonggang River. Sediments of rivers and reservoirs were similar in the pollution intensity. The average C/N value of sediments in the HRB was 12.71, indicating that the TOC was derived from algae, phytoplankton flora and fauna, followed by higher plants. The C/N value of reservoir sediments was higher than that of river sediments, indicating that the contribution of terrigenous material inputs to TOC was larger in reservoirs than in rivers.

REVIEWS

Shade tolerance and the adaptability of forest plants in morphology and physiology: A review.

YIN Dong-sheng, SHEN Hai-long

2016, 27(8):  2687-2698.  doi:10.13287/j.1001-9332.201608.018

Asbtract ( 389 )   PDF (655KB) ( 178 )  

Shade tolerance, defined as the ability to survive and grow under low light, plays an important role in the succession of forest plant communities. The mechanism of adaptation of plants to shading has become an important topic in ecology research. In this paper, we reviewed shade tole-rance of various forest plants and examined their adaptability in terms of morphology and physiology, and discussed the plasticity on growth traits, biomass distribution, crown structure, leaf morphology and physiology, leaf anatomical structure, photosynthetic parameters, carbohydrate allocation, water and nutrient utilization related to shade tolerance of forest plants. Finally, we discussed some problems with previous studies, and proposed possible future research issues.

Research advances in stable nitrogen isotope in water bodies.

FAN Li-jun, ZHAO Feng-hua, CHENG Chen

2016, 27(8):  2699-2707.  doi:10.13287/j.1001-9332.201608.003

Asbtract ( 577 )   PDF (1440KB) ( 112 )  

Water bodies’ nitrogen contamination has become more and more serious due to the effects of the intensive development of industry and agriculture. It is important to use nitrogen stable isotope data to identify the nitrogen pollution sources and study the nitrogen cycle of water bodies. This article gave an overview of basic information as follows: 1) introducing the nitrogen stable isotope, nitrogen cycle and the fractionation factors; 2) comparing the analysis techniques of nitrogen isotope separation, enrichment, transformation of different forms; 3) discussing the application of nitrogen stable isotope in natural nitrogen cycle of different water types, nitrogen pollution sources justification, the biogeochemical processes in water bodies, and the eutrophication; 4) summarizing the methods of identifying denitrification, the two attenuation mechanisms of nitrate pollution, i.e., denitrification and dilution; 5) pointing out the deficiency of the current research.

Roles of microbes in matter cycles in phycosphere niche.

ZHOU Jin, LIN Guang-hui, CAI Zhong-hua

2016, 27(8):  2708-2716.  doi:10.13287/j.1001-9332.201608.007

Asbtract ( 485 )   PDF (2169KB) ( 42 )  

Phytoplankton is the main driver of marine primary production and matter cycles. Their ecological functions have closely linked to the associated microbes. Although microbial biodiversity is high in all kinds of algal hosts (such as dinoflagellate, diatoms and blue-green algae), some he-terotrophic bacteria (Alphaproteobacteria, Gammaproteobacteria, Flavobacteria, and Actinobacteria) often appear as the dominant communities. In algae-bacteria symbiosis, microbes play important ecological roles, such as regulating microbial food web, mediating the energy flow & nutrient cycling, and maintaining the balance of ecological system. In this review, we summarized the bacterial functions in phycosphere environment, and discussed their contribution to biogeochemical cycle and co-evolution. Particularly, we attempted to take Flavobacteria and Roseobacters as the examples to reveal the metabolic behavior and survive strategies, for better understanding the ecological cha-racterization and co-evolution of “resident species” in phycosphere niche.

Research progress and development trend of quantitative assessment techniques for urban thermal environment.

SUN Tie-gang, XIAO Rong-bo, CAI Yun-nan, WANG Yao-wu, WU Chang-guang

2016, 27(8):  2717-2728.  doi:10.13287/j.1001-9332.201608.002

Asbtract ( 354 )   PDF (2638KB) ( 34 )  

Quantitative assessment of urban thermal environment has become a focus for urban climate and environmental science since the concept of urban heat island has been proposed. With the continual development of space information and computer simulation technology, substantial progresses have been made on quantitative assessment techniques and methods of urban thermal environment. The quantitative assessment techniques have been developed to dynamics simulation and forecast of thermal environment at various scales based on statistical analysis of thermal environment on urban-scale using the historical data of weather stations. This study reviewed the development progress of ground meteorological observation, thermal infrared remote sensing and numerical simulation. Moreover, the potential advantages and disadvantages, applicability and the development trends of these techniques were also summarized, aiming to add fundamental knowledge of understanding the urban thermal environment assessment and optimization.