Table of Content

18 May 2015, Volume 26 Issue 5

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Fractionation of dissolved organic carbon along soil profiles during the leaching process.

XIONG Li1,2, YANG Yu-sheng1,2, WAN Jing-juan1,2, SI You-tao1,2

2015, 26(5):  1289-1296. 

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Two distinct soil types in midsubtropical China were selected for soil sampling at the depth of 0-10, 10-20, 20-40, 40-60, 60-80, 80-100 cm for soil cores preparation. Dissolved organic carbon (DOC) extracted from recently fallen litters of Castanopsis carlesii with ultrapure water was leached through such soil cores to investigate the fractionation and retention pattern when migrating along the soil layers. The results showed the leachates out of deeper soil cores had lower concentrations and were chemically simpler, the hydrophobic pools contributed to the majority of the retention, but the proportion of retained hydrophilic materials gradually increased with the increasing soil depth. The infrared spectrum suggested that the hydrophobic materials containing aromatic rings could be easily absorbed by soils, but alkanes and simple carbohydrates would transport into subsoils with soil solution. Proportional decrease in the highly sorptive DOC restricted C sorption by subsoils, and thus the adsorption occurred mainly in 0-40 cm soil layers, suggesting that the chemical nature of DOC had a greater influence on sorption capacity of the soils than soil physicochemical properties. The retention amounts of DOC by different soil types differed significantly, which were significantly positively correlated with the contents of clay, iron and aluminum oxides.

Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest.

WANG Ning1, WANG Mei-ju1, LI Shi-lan1, WANG Nan-nan1, FENG Fu-juan1, HAN Shi-jie2

2015, 26(5):  1297-1305. 

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Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (±30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg·kg^-1, respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatialtemporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial community structure and composition.

Spatial distribution pattern of soil nitrogen in Huanghuadianzi watershed and related affecting factors.

LI Long, YAO Yun-feng, QIN Fu-cang, GAO Yu-han, ZHANG Mei-li

2015, 26(5):  1306-1312. 

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This research was conducted in Huanghuadianzi watershed in Aohan, Chifeng, Inner Mongolia. Geostatistic was used to study the spatial distribution of soil nitrogen and their affecting factors. The results showed that the soil nitrogen contents in all layers distributed as an island shape, and the high value areas were mainly distributed in the northwest of the watershed as an obvious fertile island shape, while the low value areas were mainly distributed in the south of the watershed. Nitrogen was mainly concentrated in the surface soil, and its content decreased with the increase of soil depth. The soil nitrogen content at first increased then decreased with the altitude, decreased with the slope, and showed the order of shady slope>semishady slope>semisunny slope>sunny slope in different aspects. The average soil nitrogen contents in different land use types ranked as cropland >woodland > grassland.

Absorption and distribution of K, Na and Mg in Avicennia marina seedlings under cadmium stress.

2015, 26(5):  1313-1319. 

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In this paper, mangrove seedlings Avicennia marina were treated with various contents of cadmium (0，0.5, 5, 25, 50, 100, 150 mg·L^-1). These seedlings were cultivated by manmade seawater with a salinity of 15 in sand for 90 days in a greenhouse. The absorption and distribution of elements contents (K, Na and Mg) under cadmium stress were investigated at 45th and 90th day, respectively. The results showed that the enrichment of cadmium in the different components of seedlings increased with
 the increasing cadmium stress level and exposure time. The cadmium contents in roots and cotyledons were relatively higher than in the other components, accounting for
66.9% and 16.3% of cadmium in the seedlings under the 150 mg·L^-1 cadmium stress, respectively. The fall of cotyledons could reduce the damage of cadmium stress to the whole seedlings. The Na contents increased in roots and stems and decreased in leaves and cotyledons after cadmium stress for 90 days. The K content decreased in roots and cotyledons, while had no significant change in stems and leaves. The Mg content in roots, stems, leaves and cotyledons of seedlings treated with cadmium for 90 days were lower than those of the control, and were negatively related to the cadmium content.

Effects of chilling stress on antioxidant system and ultrastructure of walnut cultivars.

TIAN Jing-hua1, WANG Hong-xia2, ZHANG Zhi-hua2, GAO Yi1

2015, 26(5):  1320-1326. 

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In order to reveal cold hardiness mechanisms and ascertain suitable cold hardiness biochemical indicators of walnut (Juglans regia), three walnut cultivars ‘Hartley’, ‘Jinlong 1’ and ‘Jinlong 2’ with strong to weak tolerance of chilling stress, were used to investigate variations of leaf antioxidant enzyme activity and superoxide anion (O₂^-_·) content in one yearold branches under chilling stress at 1 ℃ in leafexpansion period. The mesophyll cells ultrastructure of ‘Hartley’ and ‘Jinlong 2’ under chilling stress were also observed by transmission electron microscope. The results showed that the superoxide dismutase (SOD) and peroxidase (POD) enzyme activities were the strongest and O₂^-_· content was the lowest in chillingtolerant cultivar ‘Hartley’ under chilling stress among the three cultivars. The ultrastructure of the mesophyll cells was stable, and chilling injury symptoms of the leaves were not observed. In chillingsensitive cultivar ‘Jinlong 2’, the SOD, POD and catalase enzyme (CAT) activities decreased sharply, and the O₂^-_· content was kept at a high level under chilling stress. The ultrastructure of the mesophyll cells was injured obviously at 1 ℃ for 72 hours. Most of chloroplasts were swollen, and grana lamella became thinner and fewer. A number of chloroplasts envelope and plasma membrane were damaged and became indistinct. At the same time, the edges of some of ‘Jinlong 2’ young leaves became watersoaked. It was concluded that the ultrastructure stability of mesophyll cells under chilling stress was closely related to walnut cold hardiness. SOD, POD enzyme activities and O₂^-_· content in walnut leaves could be used as biochemical indicators of walnut cold hardiness in leafexpansion period. There might be a correlation between the damage of cell membrane system and reactive oxygen accumulation under chilling stress.

 

Leaf morphology and photosynthetic characteristics of wild Ussurian pear in China.

DONG Xing-guang, CAO Yu-fen, TIAN Lu-ming, WANG Kun, ZHANG Ying, QI Dan

2015, 26(5):  1327-1334. 

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The wild Ussurian pear was the most important wild pear resource in northern China, belonging to the most hardiness species. Taking 48 accessions of wild Ussurian pear and 2 accessions of cultivated Ussurian pear as test materials, this paper studied the morphology of leaves, chlorophyll content, and photosynthetic characteristics. We compared the difference between the wild and cultivated Ussurian pear, analyzed the photosynthetic characteristics of wild Ussurian pear, clarified the interrelationships between the indices, and established significant linear equations of photosynthesis and waterrelated physiological indices. The results showed that the leaf morphological index, chlorophyll content and photosynthetic indices for cultivated Ussurian pear were significantly lower than their average values for wild Ussurian pear. The specific leaf area (SLA), leaf dry matter content (LDMC), and intercellular CO₂ concentration had low coefficients of variation, and the other 8 indices had variation coefficient indices between 0.12-0.41. So, the level of diversity was high, indicating obvious difference in photosynthetic characteristic of wild pear resources in China. The photosynthetic indices were significantly correlated with chlorophyll composition (Chl a/b) and LDMC. The photosynthetic rate had significant exponential correlation with the intercellular CO₂ concentration, transpiration rate, and stomatal conductance. The photosynthetic rate was mainly affected by stomatal limitation. The wild variety ‘Jinzhoushanli’ was selected as high photosynthetic genetic resource.

 

Effects of drip irrigation methods on the regulation between root and crown function of ‘Cabernet Sauvignon’ seedlings.

YU Kun, YU Song-lin, LIU Huai-feng, ZHAO Bao-long, WANG Wen-jing

2015, 26(5):  1335-1342. 

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The objective of this experiment was to study the effects of three irrigation methods, i.e., subsurface drip irrigation with a tank system (SDI), plastic film mulcheddrip irrigation (MDI), and conventional drip irrigation (DI) on the regulation between root and crown function of Vitis vinifera ‘Cabernet Sauvignon’ seedlings. The results showed that both the SDI and MDI systems promoted the growth of the grape seedlings compared with DI, with the SDI system promoting the root growth, and MDI system promoting the aboveground growth. Root area, root volume, and root activity and SOD enzyme activity in the SDI treatment were greater than those of MDI or DI treatment in the 20-60 cm soil layer. SDI treatment increased root penetration and physiological activity. Symptoms of drought stress appeared earlier in DI treatment than in either MDI or SDI treatment in the same watering schedule. Net photosynthetic rate (P_n) and stomatal conductance (g_s) of leaves were higher in SDI and MDI treatments than in DI treatment. Φ_PSⅡ and q_P at 12:00-14:00 were lower in the MDI treatment than in SDI treatment at 7 d after irrigation, suggesting that the degree of photoinhibition in the fluorescence process in MDI treatment was more than that in SDI treatment. The high biomass and physiological activity of roots in the 20-40 cm depth could increase both of total plant biomass and aboveground biomass. The regulation between root and crown function was better in SDI treatment than in MDI and DI treatments. Therefore, SDI could be used as an alternative technique of watersaving irrigation practices.

Effects of NO₃^- stress on cucumber seedling growth and magnesium absorbing under suboptimal temperature.

YANG Quan-yong1, WANG Xiu-feng1,2, HAN Yu-rui1, YANG Jing-jing1, WEI Min1,2,3, YANG Feng-juan 1,2, SHI Qing-hua1,2, LI Yan1

2015, 26(5):  1343-1350. 

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The effects of NO₃^- stress on the growth and the magnesium absorption of cucumber seedlings were investigated after 1 and 14 d of suboptimal temperature
 ［18 ℃/12 ℃ (day/night)］ treatment. The results indicated that the growth, net photosynthetic rate, transpiration rate, F_v/F_m and Φ_PSII of cucumber seedlings were significantly inhibited by NO₃^- stress under suboptimal temperature. The magnesium content of cucumber seedlings was also significantly decreased compared with control treatment, especially in the Ⅳ treatment （suboptimal temperature +140 mmol·L^-1 NO₃^-+1 mmol·L^-1 Mg²⁺）, and the antagonistic impact of magnesium ion absorption on the absorption of potassium and calcium ion was observed. The magnesium deficiency symptom of cucumber seedlings could be partly alleviated by increasing the concentration of magnesium ion in the nutrient solution.

Effects of low magnesium on photosynthesis characteristics and antioxidant system in cucumber seedlings under low temperature.

2015, 26(5):  1351-1358. 

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The effects of low magnesium (30% Mg) stress on photosynthesis characteristics and antioxidant system in ‘Jinyou 3’ cucumber (Cucumis sativa) seedlings under low temperature (day/night temperature was 12 ℃/8 ℃) were investigated, with Hoagland nutrient solution treatment as the control. The results showed that the 30% Mg treatment showed a significantly lower Mg content in leaves, compared with the control. However, no marked difference in roots between the 30% Mg treatment and the control was found. Low temperature significantly decreased the chlorophyll content, net photosynthetic rate (P_n), stomatal conductance (g_s), and carboxylation efficiency (CE), while increased the intercelluar CO₂ concentration (C_i). The 30% Mg treatment showed significantly lower chlorophyll content, P_n, g_s and CE, compared with the control. No marked change was found in C_i between the 30% Mg treatment and the control. Low magnesium stress resulted in a more serious damage in chloroplast membrane under low temperature, and showed lower chloroplasts, grains and lamellas, while more and larger starch grains in cucumber seedlings. Low magnesium stress also led to an increase in MDA content, while a decrease in activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). These data suggested that magnesium deficiency caused by its hindered transportation under low temperature was the main reason for the chlorosis of cucumber leaves. The decrease in P_n was mainly caused by the nonstomatal limitation. Low magnesium stress increased the influence of low temperature on P_n, and the resulting decline in P_n was caused by the stomatal limitation.

Effects of temperature-shifted controlling on bolting and flowering of endive.

HE Zhong-qun1, WANG Jun2

2015, 26(5):  1359-1364. 

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Temperature sensitive periods and growth characteristics of endive under different temperatures were investigated in greenhouse by weekly reciprocal transferring experiment condition between warm (17 ℃) and cold (average 10.5 ℃) environment. The results indicated that difference in growth rate of endive was significant in cold and warm environments. There was no  temperature sensitive period in endive, and it could feel outside temperature, thus, conducted vernalization induction in setting temperature range (2-17 ℃). Meanwhile, low temperature favored the flower bud differentiation. Endives all completed flower bud differentiation and bloting either in warm or in cold environment. It took 24 days to complete flower bud differentiation in cold environment and 60 days in warm environment, and bolting was 7 days later in warm environment than in cold environment. From seeding to bolting, it took 111 days in warm environment and 104 days in cold environment, respectively. After flowering induction, the seeding bolting rate from warm environment to cold environment was obviously higher than that from cold to warm environment and higher temperature led to faster bolting in this period.

Effect of the same amount of faba bean fresh straw returning with different ratios of chemical fertilizer on single cropping late rice.

WANG Jian-hong1, ZHANG Xian1, CAO Kai1, HUA Jin-wei2

2015, 26(5):  1365-1372. 

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A field experiment was conducted on paddy soil derived from alluvial materials at Bihu Town, Lishui City, Zhejiang Province, China to explore the effects of combined application of faba bean fresh straw and differentrate chemical fertilizer on nutrient uptake, nutrient use efficiencies, and yields of single cropping late rice and to determine the optimal rate of chemical fertilizer under the condition of application of faba bean fresh straw at the rate of 15 t·hm^-2 (GM₁₅) in 2012, April to December. The experiments consisted of 7 treatments: CK (no fertilizers), CF (conventional chemical fertilizer rate), and combined application of 15 t·hm^-2 of faba bean fresh straw and 0%, 20%, 40%, 60% and 80% of the conventional chemical fertilizer rate. The results showed that the highest total uptake amounts of N, P and K by the aboveground part were obtained from the treatments of GM₁₅+60%CF and GM₁₅+80%CF, but the highest nutrient agronomy use efficiencies of N, P and K in rice grains were obtained from the treatments of GM₁₅+60%CF and GM₁₅+40%CF. The agronomy use efficiencies and physiological use efficiencies of N, P, and K were significantly correlated with rice grain yields, thus they could be used for accurate comprehensive evaluation of fertilizer efficiencies of N, P, and K. Compared with no fertilizer treatment, the treatments of 100%CF and combined application of faba bean fresh straw and differentrate chemical fertilizer increased rice gain yields by 25.0% and 6.1%-29.2%, respectively. In the cropping system of faba beansingle cropping late rice, returning of 15 t·hm^-2 faba bean fresh straw to the paddy field did not result in the runt seedling of rice. From the point of improving fertilizer use efficiency and reducing environmental risk perspective, the optimum rate of chemical fertilizer was 60% of the conventional chemical fertilizer rate when 15 t·hm^-2 of faba bean fresh straw was applied.

Comparison on submergence tolerance of different type rice at tillering stage in lower reaches of Yangtze River.

LIU Ming, LI Yan, GUO Gui-hua, LIU Hai-yan, LI Gang-hua, WANG Shao-hua, LIU Zheng-hui, DING Yan-feng

2015, 26(5):  1373-1381. 

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The agronomic traits, physiological characteristics and yield traits of 9 rice varieties popularized in lower reaches of Yangtze River were investigated under submergence stress at the tillering stage. The differences of environmental adaptability to submergence stress for conventional japonica rice, indica hybrid rice and hybrid japonica rice, were also analyzed and compared. The results showed that the stem and the upper three leaves under submergence stress were elongated compared with the control. And the elongation of the different varieties was shown as, hybrid japonica rice > indica hybrid rice > conventional japonica rice. As to the numbers of tillers and green leaves, and the aboveground dry mass, the reduction of indica hybrid rice was all between hybrid japonica rice and conventional japonica rice. The damage of hybrid japonica was the lightest. The content of MDA in the leaves of conventional japonica rice increased, while the activities of SOD and CAT decreased. However, the performances of hybrid japonica rice and indica hybrid rice were opposite with conventional japonica rice. The yield loss of conventional japonica rice was significantly higher than those of the other types of rice. These results suggested that the submergence tolerance ability of hybrid japonica rice is superior to indica hybrid rice, and the submergence tolerance ability of conventional japonica rice is the weakest.

Effects of ridge and furrow rain harvesting with supplemental irrigation on winter wheat photosynthetic characteristics, yield and water use efficiency in Guanzhong irrigation district.

ZHANG Yu1,2, HAN Qing-fang1,2, CHENG Xue-feng1,2, YANG Shan-shan1, JIA Zhi-kuan1,2, DING Rui-xia1,2, REN Xiao-long1,2, NIE Jun-feng1,2

2015, 26(5):  1382-1390. 

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A field experiment was conducted to determine the regulation of crop photosynthesis and output and water saving effect under ridge and furrow rain harvesting with supplemental irrigation in Guanzhong irrigation district. The experiment was set with 5 treatments with irrigation at returning green stage, and the widths of both ridge and furrow being 60 cm. T₁, T₂ and T₃ were in the ridge and furrow rain harvesting planting pattern, with the irrigation volumes being 0, 375 and 750 m³·hm^-2 respectively, T₄ was flat planting with irrigation (border irrigation) of 750 m³·hm^-2 and CK was flat planting without irrigation. Effects on winter wheat photosynthetic organs, photosynthetic rate, yield and water use efficiency, etc. were tested. The results showed that compared with T₄, T₁, T₂ and T₃ treatments  increased the grain yield by 2.8%, 9.6% and 18.9%, improved the harvest index by 2.0% to 8.5%, advanced the flag leaf chlorophyll content by 41.9% to 64.4% significantly, and improved the 0-40 cm layer soil moisture content by 0.1%-4.6% during the whole growth period. Photosynthetic rates at the flowering and filling stages also increased by 22.3% to 54.2% and -4.3% to 67.2%, respectively. Total  water use efficiencies (WUE_y) were 17.9%, 10.4% and 15.4% higher than that of T₄, and 69.3%, 58.6% and 65.7% higher than that of CK (P<0.05), respectively, and enhanced precipitation utilization efficiency (PUE) by 94.3%-124.5% than CK. Leaf areas of T₂ and T₃ treatments at each growth stage were significantly higher than that of T₄ and CK, irrigation water use efficiencies (IUE) were 119.1% and 18.8% higher than that of T₄, respectively. Therefore, it was concluded that ridge and furrow rain harvesting cultivation could maintain higher grain yield than border irrigation without irrigation or with irrigation reduction by 50%. The utilization efficiency of irrigation water under the condition of irrigation reduction by 50% was improved significantly, and the ridge and furrow rain harvesting could significantly improve whole cropland water use efficiency in the year of less rainfall.

 

Effects of drought stress on performance of photosystem Ⅱ in maize seedling stage.

GAO Jie, ZHANG Ren-he, WANG Wen-bin, LI Zhi-wei, XUE Ji-quan

2015, 26(5):  1391-1396. 

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Maize cultivar Shandan 609 was used to determine the effects of drought stress on photosystemⅡ, dry matter accumulation, protective enzyme activity and
  proline content at seedling stage in pot experiment. Two drought treatments (moderate drought and severe drought) were tested. The results showed that dry matter accumulation, leaf area and plant height of cultivar shaandan 609 decreased significantly with the increasing  drought stress. The less grouped PSⅡunits (L_band>0), severely damaged OEC (K_band>0), and the inhibited acceptor side (Ψ_o significantly decreased) resulted in the overall dropped performance of PSⅡ (PI-ABS). Under the condition of moderate and severe drought stress, the activities of superoxide, peroxidase, catalase and   proline content increased significantly, which were 1.3, 1.1, 1.2, 5.8 and 1.1, 3.3, 1.5, 15.0 times of control (CK), respectively. Those results indicated that damage of PSⅡ acceptor and donor side under drought stress led to the decline of PSⅡ performance, which was likely to cause the decline of dry mater accumulation of maize cultivar Shandan 609, while protective enzymes and proline as protective substance in plant played a positive role in drought resistance.

Effects of tillage at pre-planting of winter wheat and summer maize on leaf senescence of summer maize.

LI Xia, ZHANG Ji-wang, REN Bai-zhao, FAN Xia, DONG Shu-ting, LIU Peng, ZHAO Bin

2015, 26(5):  1397-1403. 

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This study explored the effects of different tillage treatments at pre-planting winter wheat and summer maize on leaf senescence physiological characteristics of summer maize in double cropping system. Zhengdan 958 was used as experimental material. Three tillage treatments, including rotary tillage before winter wheat seeding and notillage before summer maize seeding (RN), moldboard plow before winter wheat seeding and notillage before summer maize seeding (MN), and moldboard plow before winter wheat seeding and rotary tillage before summer maize seeding (MR), were designed to determine the effects of different tillage treatments on leaf area (LA), leaf area reduction, photosynthetic pigments content, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities and malondialdehyde (MDA) content in ear leaves of summer maize after tasselling (VT). LA of MN and MR were higher than that of RN from VT to 40 days after tasseling (VT+40) and LA reduction of MR was the highest after VT+40. As for MR, MN and NT, the photosynthetic pigments content got the maximum value at 20 days after tasselling (VT+20) and then decreased, following the change of unimodal curve. At VT+20, the contents of chlorophyll a in MR and MN were increased by 11.4% and 9.7%, the contents of chlorophyll b in MR and MN were increased by 14.9% and 15.9%, compared with RN. The soluble protein content in ear leaves decreased following the growth process in all treatments, and that of MR and MN remained 11.5% and 24.4% higher than that of RN from VT to VT+40. SOD, CAT and POD activities of three treatments got the maximum values at VT+20 and then decreased, following the change of unimodal curve. MDA content increased following the growth process in all treatments and that of RN always remained at high levels. Grain yields of MN and MR were 24.0% and 30.6% greater than that of RN, respectively. Grain yield of MR was 5.2% higher than that of MN. In conclusion, the ability of leaf senescence resistance of MN was improved, which was helpful to increase the yield of summer maize.

Degradation of lignocellulose in the corn straw by Bacillus amyloliquefaciens MN-8.

LI Hong-ya1, LI Shu-na1, WANG Shu-xiang1, WANG Quan1, XUE Yin-yin2, ZHU Bao-cheng1

2015, 26(5):  1404-1410. 

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Microbial degradation of lignocellulose is one of the key problems that need to be solved urgently in the process of utilizing biomass resource. Bacillus amyloliquefaciens MN-8 is our previously isolated bacterium capable of degrading lignin. To determine the capability of strain MN-8 to degrade lignocellulose of corn straw,
B. amyloliquefaciens MN-8 was inoculated and fermented with solidstate corn straw powderMSM culture medium. The changes in the enzyme activity and degradation products of lignocellulose were monitored in the process of fermentation using the FTIR and GC/MS. The results showed that B. amyloliquefaciens MN8 could produce lignin peroxidase, manganese peroxidase, cellulase and hemicellulase enzymes. The activities of all these enzymes reached the peak after being incubated for 10-16 days, and the highest enzyme activities were 55.0, 16.7, 45.4 and 60.5 U·g^-1, respectively. After 24 d of incubation, the degradation percentages of lignin, cellulose and hemicellulose were up to 42.9%, 40.6% and 27.1%, respectively. The spectroscopic data by FTIR indicated that the intensities of characteristic absorption peaks of lignin, cellulose and hemicellulose of the corn straw were decreased, indicating that the lignocellulose was degraded partly after being fermented by B. amyloliquefaciens MN-8. GC/MS analysis also demonstrated that strain MN-8 could degrade lignocellulose efficiently. It could depolymerize lignin into some monomeric compounds with retention of phenylpropane structure unit, such as amphetamine, benzene acetone and benzene propanoic acids,  by the rupture of β-O₄ bond connected between lignin monomer, and it further oxidized some monomer compounds into Cα carbonyl compounds, such as 2-amino-1-benzeneacetone and 4-hydroxy-3,5-dimethoxyacetophenone. The GC/MS analysis of the degradation products of cellulose and hemicellulose showed that there were not only monosaccharide compounds, such as glucose, mannose and galactose,  but also some glycolysis products including formic acid, acetic acid, propionic acid, 1,1-ethanediol and 3-hydroxy butyric acid. Our results demonstrated that B. amyloliquefaciens MN-8 is capable of degrading lignocelluse of the corn straw effectively and the degradation capacity depends on the lignocellulase activity.

Effects of exogenous EBR and NO signal on antioxidant system and low response gene expression under cold stress on maize embryo.

MA Jin-hu, XING Guo-fang, YANG Xiao-huan, WANG Yu-guo, DU Hui-ling

2015, 26(5):  1411-1418. 

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In this study, Xianyu 335, a maize hybrid, was used to investigate the effects of 24Epibrassinolide (EBR, a synthetic BR) on antioxidant capacity and lowtemperature response gene expression in maize embryo germination under low temperature (LT) stress. The germination rate of maize seeds under LT stress was not affected by EBR, but the seed activity index and seedling growth were improved. EBR increased the activities of some antioxidative enzymes including SOD, POD, CAT and GR, and the contents of nonenzymatic antioxidants, such as GSH and proline, and induced the accumulation of nitric oxide (NO). NO scavenging cPTIO and NOS inhibitor LNAME decreased but NO donor SNP increased the enzyme activities of CAT and POD, and the content of proline, indicating NO mediated the EBRinduced antioxidant capacity. The gene expression pattern analysis showed that the expression of P₅-CS₁, CBF₁, CBF₃ and COR₁₅a was induced by LT stress, and further increased by EBR treatment in maize embryo, while their expression was suppressed by cPTIO and L-NAME, and improved by SNP, which implied LTresponsed genes were regulated by NO. These results demonstrated that NO was involved in the EBRinduced LT tolerance in maize embryo by modulating the antioxidative capacity and the expression of LTresponsive genes.

 

Influence of drought on leaf photosynthetic capacity and root growth of soybeans at grain filling stage.

2015, 26(5):  1419-1425. 

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A droughtresistant soybean cultivar Jinda 70 and a droughtsensitive soybean cultivar Jindou 26 were taken as test materials. At the grain filling stage, the cultivars were subject to three water treatments including sufficient water supply, light drought stress, and severe drought stress by using pot experiments for research on influence of drought on leaf photosynthetic capacity and root growth of soybeans. The results showed that as the degree of drought stress was aggravated, all of the indices including leaf area, chlorophyll content, net photosynthetic rates (P_n), stomatal conductance (g_s), transpiration rate (T_r), intercellular CO₂ concentration (C_i), plant mass, plant height, seed yield, and harvest index in the two cultivars declined. The root length and root mass increased under light drought stress, and decreased under severe drought stress. Rootshoot ratio ascended as the degree of drought stress was aggravated. Under severe drought stress, the increase of rootshoot ratio of the droughtresistant soybean cultivar Jinda 70 was up to 135.7%, which was higher than the that (116.7%) of the droughtsensitive soybean cultivar Jindou 26. Simultaneously, leaf area and chlorophyll content in Jinda 70 were respectively 69.3% and 85.5% of those in the control, which were better than those of Jindou 26. g_s and P_n  of Jinda 70 respectively declined 67.9% and 77.9%, but still lower than those of Jindou 26. Therefore, the decline range of harvest index of Jinda 70 was 43.8%, which was lower than the range of 78.8% of Jindou 26. The Biplot revealed that under different dry treatments, there were significant positive correlations among the six indexes including leaf area, chlorophyll content, P_n, g_s, T_r, and C_i of the two cultivars. There were also significant positive correlations among the six indices including plant mass, plant height, root length, root mass, seed yield, and harvest index. Rootshoot ratio only had significant positive correlation with root mass and had significant negative correlations with other five indices.

Effects of sugarcane-soybean intercropping on cane yield, quality and economic benefit under low nitrogen condition.

YANG Jian-bo1,2, PENG Dong-hai1,2, QIN Liu-dong1, XING Yong-xiu1, LI Yang-rui1,3, YANG Li-tao1,3

2015, 26(5):  1426-1432. 

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To explore the effects of sugarcane-soybean intercropping on cane yield, quality and economic benefit, three sugarcane cultivars (B8, ROC22 and GT21) planted under sugarcane monoculture and sugarcanesoybean intercropping with low nitrogen fertilization (urea application of 150 kg·hm^-2). The field design was a splitplot with the cropping pattern being the principal factor and the sugarcane cultivar being the secondary factor. The results showed that the millable stalks, stalk diameter, cane yield and sugar production were significantly affected by sugarcanesoybean intercropping while the cane quality wasn’t changed obviously. Compared with sugarcane monoculture, the stalk diameter, millable stalks, cane yield and sugar production in the intercropping system were increased by 5.1%-8.7%, 7.9%-31.0%, 9.0%-40.5% and 5.6%-39.5%, respectively. The total incomes of cane and soybean, and sugar and soybean were increased by 58900-79300 yuan·hm^-2 and 58300-77200 yuan·hm^-2, respectively. Among the three sugarcane cultivars in the sugarcanesoybean intercropping pattern, the economic benefit was the highest in ROC22, while the ratoon cane yields of GT21 and B8 were higher than that of ROC22. The results also indicated that sugarcanesoybean intercropping is an effective planting method to reduce nitrogen fertilizer
application and increase economic income in sugarcane production.

Effects of calcium fertilizer application on peanut growth, physiological characteristics, yield and quality under drought stress.

GU Xue-hua1, SUN Lian-qiang1, GAO Bo1, SUN Qi-ze1, LIU Chen1, ZHANG Jia-lei2, LI Xiang-dong1

2015, 26(5):  1433-1439. 

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An experiment was carried out to study the effects of different rates of calcium application on peanut growth, physiological characteristics, yield and quality under drought stress at pegging stage and pod setting stage in pool cultivation with rainproof, using variety 606 as experimental material. The results showed that applying Ca fertilizer under drought stress could promote peanut growth, increase the chlorophyll content, leaf photosynthetic rate and the root vitality, increase the recovery ability of peanut during rewatering after drought stress, alleviate the impact of drought stress on peanut. Applying Ca fertilizer under drought stress increased pod and kernel yields because of the increase of kernel rate and pod number per plant. It also increased the fat and protein contents of peanut kernel, and improved peanut kernel quality under drought stress. It was suggested that 300 kg·hm^-2 Ca application is the best choice to alleviate the impact of drought stress on peanut.

 

Effects of phosphorus fertilizer on the root system and its relationship with the aboveground part of fluecured tobacco.

WANG Yan-li1,2, LIU Guo-shun1,2, DING Song-shuang1,2, WANG Jing2, LI Yuan-bo1,2, DONG Xiao-li3

2015, 26(5):  1440-1446. 

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Using ‘Yuyan 10’ as the material, the effects of different phosphorus fertilizer application on root characteristics of tobacco, such as root dry mass and the difference of dry matter distribution and mineral nutrient accumulation between its above and underground parts were investigated. The results showed that the growth of fluecured tobacco root system and the distribution of dry matter to the aboveground part were significantly promoted by phosphorus fertilizer application. The application of 30 kg P₂O₅·hm^-2 led to the maximums of root dry mass, root volume, root activity and the minimum of root to shoot ratio. The maximum nutrient accumulation rates of root and leaf appeared 57-66 days after transplanting and 44-55 days after transplanting, respectively. Phosphorus could not only promote the mineral nutrition absorption of tobacco and the earlier appearance of maximum nutrient accumulation, but significantly promote the nutrient accumulation of the aboveground part. But, the positive effects described above would be weakened when the amount of phosphorus fertilizer was more than 30 kg P₂O₅·hm^-2. Therefore, it’s necessary to control the
amount of phosphorus application to improve the quality of tobacco leaves.

 

Correlation between endogenous harmful components in mainstream cigarette smoke and chemical constituents in tobacco leaves.

GENG Zhao-liang1, ZHANG Jie1, GE Yong-hui1, XIANG Zhang-min1, CAI Kai1, ZHU Xian-ling2, LI Ji-xin3, FENG Yong-gang1

2015, 26(5):  1447-1453. 

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Correlation analysis between main chemical constituents of tobacco leaves and endogenous harmful components in mainstream cigarette smoke was conducted. Leaf stalk positions exhibited a high relation with endogenous harmful components and hazard index (H). Upper stalk position leaves had greater release of 1-butanone,4-(methylnitrosoamino)-1-(3-pyridinyl) (NNK), B\[a\]P. HCN, NH₃ and phenol in mainstream cigarette smoke, and a higher hazard index than middle position leaves except for crotonaldehyde, which had greater release from middle position leaves. Different endogenous harmful components in mainstream cigarette smoke presented complicated correlation with main chemical constituents in tobacco. The same type of leaf chemical constituents presented different correlations with various endogenous harmful components in mainstream cigarette smoke. Cigarette hazard index showed significantly positive correlations with contents of nicotine, protein, total nitrogen, major polyphenols and organic acids, while significantly negative correlation with potassium and carbonaceous substances, such as total sugars, reducing sugars and starch. The results suggested that properly increasing potassium content and decreasing nitrogenous constituents in cured tobacco leaf may reduce the cigarette hazard index.

 

Characteristics of the preferential flow and its response to irrigation amount in oasis cropland.

2015, 26(5):  1454-1460. 

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Preferential flow is a physical process describing how water and solutes move along certain pathways through soil profile. Studying the cropland preferential flow patterns and its influential factors could quantify the deep percolation, improve water and fertilizer use efficiency and reduce the risk of agrochemicals contaminating shallow groundwater in oasis cropland. The dye tracer experiments were carried out in field oasis cropland, using a brilliant blue FCF solution. The results showed that between ridge and furrow, the number of stained paths densities differed significantly at the 7.3-16.7 cm depth of the soil profiles, while the maximum dye depth had no significant difference. The main influence factors of the maximum stained depth were the irrigation amount and the ant burrows. The maximum stained depth was (43.1±5.9) cm with the mean irrigation amount of 120 mm, however, the maximum stained depth was (68.3±7.6) cm with the irrigation amount of 55 mm under the influence of the ant burrows. Root played an important role in preferential flow, but only the fine roots (Φ≤2 mm) were significantly related to the preferential flow in oasis cropland, while the coarse roots were not. In oasis cropland, the characteristics of the preferential flow were influenced by the irrigation amount, the furrow and ridge planting, the ant burrows and the roots, and the ant burrows were an uncertain factor which affected the maximum infiltration depth of the preferential flow.

Establishing a minimum data set of soil quality assessment for cold-waterlogged paddy field in Fujian Province, China.

WANG Fei, LI Qing-hua, LIN Cheng, HE Chun-mei, ZHONG Shao-jie, LI Yu, LIN Xin-jian

2015, 26(5):  1461-1468. 

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The yields of coldwaterlogged (CW) paddy fields widely spreading in Jiangnan mountainous areas are moderate or low but have a high potential to be increased. Based on data including 41 soil characteristics of 17 pairs of typical surface soils of cold-waterlogged paddy field and non coldwaterlogged (NCW) paddy field at a neighboring landscape unit in Fujian Province, various index differences of soil properties and causes between CW paddy field and NCW paddy field were systematically studied, and a minimum data set (MDS) of soil quality assessment for CW paddy field was established by principal component analysis. By pair analysis, soil characteristics of CW paddy field showed that the content of organic matter increased by 31.7%, but the microbial biomass C decreased by 37.8%, which belonged to active soil organic matter component. The content of ferrous iron (Fe²⁺) increased by 177.0%, but the available phosphorus (P) and potassium (K) decreased by 52.3% and 22.8%, respectively. Catalase and invertase activities increased by 58.3% and 22.1%, but phosphatase, nitrate reductase activities and microflora decreased by 47.8%, 66.6% and 29.8%-46.0%, respectively. The sand content increased about 8.0%, but the water immersed bulk density decreased by 25.8%. There were significant differences of indices for 28 of all 41 soil characteristics. Five principal components cumulatively exhibiting about 78.5% contribution were concluded from the 28 soil characteristics to reflect characteristics related to soil biochemistry, active organic nitrogen, reducing barriers, physical and chemical nutrients, respectively. Eventually, correlation analysis combined with expert experience method were applied to optimize MDS containing six factors for soil quality assessments, including C/N, bacteria, microbial biomass N, total reducing agents, physical sand and total P.


 

Influence of paddy rice-upland crop rotation of cold-waterlogged paddy field on crops production and soil characteristics.

WANG Fei1, LI Qing-hua1, LIN Cheng1, HE Chun-mei1, ZHONG Shao-jie1, LI Yu1, LIN Xin-jian1, HUANG Jian-cheng2

2015, 26(5):  1469-1476. 

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Two consecutive years (4-crop) experiments were conducted to study the influence of different paddy rice-upland crop rotation in cold-waterlogged paddy field on the growth of crops and soil characteristics. The result showed that compared with the rice-winter fallow (CK) pattern, the twoyear average yield of paddy rice under four rotation modes, including rape-rice (R-R), spring corn-rice (C-R), Chinese milk vetch-rice (M-R) and bean-rice (B-R), were increased by 5.3%-26.7%, with significant difference observed in C-R and R-R patterns. Except for M-R pattern, the annual average total economic benefits were improved by 79.0%-392.4% in all rotation pattern compared with the CK, and the ration of output/input was enhanced by 0.06-0.72 unit, with the most significant effect found in the C-R pattern. Likewise, compared with the CK, the contents of chlorophyll and carotenoid, and net photosynthetic rate (P_n) of rice plant were all increased during the fulltillering stage of rice in all rotation patterns. The rusty lines and rusty spots of soils were more obvious compared with the CK during the rice harvest, particularly in R-R, C-R and B-R patterns. The ratio of waterstable soil macro aggregates of plough layer of soil (>2 mm) decreased at different levels in all rotation patterns while the ratios of middle aggregate (0.25-2 mm, expect for M-R) and micro aggregate of soil (<0.25 mm) were opposite. There was a decreasing trend for soil active reducing agents in all rotation patterns, whereas the available nutrient increased. The amounts of soil bacteria in CR and B-R patterns, fungi in B-R rotation pattern, cellulose bacteria in R-R, C-R and B-R patterns and Nfixing bacteria in B-R pattern were improved by 285.7%-403.0%, 221.7%, 64.6-92.2% and 162.2%, respectively. Moreover, the differences in all microorganisms were significant. Thus, based on the experimental results of coldwaterlogged paddy field, it was concluded that changing from single cropping rice system to C-R, R-R and B-R rotation patterns had good effect in terms of improving total yield and economic benefits, and soil physical and chemical properties were improved.

Regional difference of NPK fertilizers application and environmental risk assessment in Jiangsu Province, China.

LIU Qin-pu

2015, 26(5):  1477-1483. 

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It is of great importance to have a deep understanding of the spatial distribution of NPK fertilizers application and the potential threat to the ecological environment in Jiangsu Province, which is helpful for regulating the rational fertilization, strengthening the fertilizer use risk management and guidance, and preventing agricultural nonpoint pollution. Based on the environmental risk assessment model with consideration of different impacts of N, P, K fertilizers on environment, this paper researched the regional differentiation characteristic and environmental risk of intensity of NPK fertilizer usages in Jiangsu. Analystic hierarchy process (AHP) was used to determine the weithts of N, P, K. The environmental safety thresholds of N, P, K were made according to the standard of 250 kg·hm^-2 for the construction of ecological counties sponsered by Chinese government and the proportion of 1:0.5:0.5 for N:P:K surposed by some developed countries. The results showed that the intensity of NPK fertilizer application currently presented a gradually increasing trend from south to north of Jiangsu, with the extremum ratio of 3.3, and the extremum ratios of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer were 3.3, 4.5 and 4.4, respectively. The average proportion of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer of 13 cities in Jiangsu was
1:0.39:0.26. Their proportion was relatively in equilibrium in southern Jiangsu, but the nutrient structure disorder was serious in northern Jiangsu. In Jiangsu, the environmental risk index of fertilization averaged at 0.69 and in the middlerange of environmental risk. The environmental risk index of fertilizer application in southern and central Jiangsu was respectively at the low and moderate levels, while that of cities in northern Jiangsu was at the moderate, serious or severe level. In Jiangsu, the regional difference of fertilizer application and environmental risk assessment were affected by many factors, including physical and economic conditions, government policy, management system, technology, and management methods.

 

Processes of earth road regolith erosion in loess area.

LI Jian-ming1, QIN Wei2, ZUO Chang-qing2, WANG Wen-long1,3, GUO Ming-ming1, OUYANG Chao-bo1

2015, 26(5):  1484-1494. 

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Based on field investigation, the processes of earth road regolith erosion were studied under indoor simulated rainfall. Results showed that the runoff initiation time for both regolith and earth road surface erosion decreased with the increasing rainfall intensity and slope steepness. With the increase in regolith thickness, the initiation time for earth road surface erosion lagged for 2-5 min. When the regolith thickness was ≤0.5 cm, the runoff rate turned to be stable at 2 min after runoff generation, and the average runoff rate increased with the increasing rainfall intensity and decreased with the increasing slope steepness. When the regolith thickness was ≥1.0 cm, runoff rate turned to be stable at 3 min after runoff generation, and the average runoff rate increased linearly with the rainfall intensity but exhibited a gradually decreasing trend after the first increment with the increasing slope steepness. The critical point for regolith erosion decreased with the increasing rainfall intensity and slope steepness. With the regolith thickness of ≤0.5 cm, the erosion rate increased with the increasing rainfall intensity, with the erosion rate ranging from 24.5% to 434.4%, and the erosion rates for 8° and 16° slopes were 2.4 times as those for 2° and 4° slopes. With the regolith thickness of ≥1.0 cm, the erosion rate turned to be stable about 9 min after runoff generation and increased with the increasing rainfall intensity and slope. With the increasing slope steepness,  the erosion form changed from sheet erosion to rill erosion and then to headward
erosion. The average erosion amount over 10 min single rainfall for the regolith thickness of ≥1.0 cm was 1.3 times as that for the regolith thickness of ≤0.5 cm, while it was 2.7 times as that at the stage of regolith erosion alone. With the regolith thickness of ≤0.5 cm, the erosion amount had a significant correlation with rainfall intensity, and runoff volume with slope steepness. With the regolith thickness of ≥1.0 cm, both runoff and sediment yields in 10 min single rainfall had a significant correlation with rainfall intensity. The proportion of regolith erosion to the combined erosion increased with the increasing regolith thickness, while the road erosion was the main form at small regolith thickness.

Potential ecological risks assessment of heavy metals in the reservoir sediment of the western Haihe River basin.

CHENG Xian1,2, WANG Rui-lin2,3, WANG Jian-li1, SUN Ran-hao2

2015, 26(5):  1495-1500. 

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The reservoirs distributed in the western part of Haihe River basin play a key role in drinking water supply in the densely populated region. The potential ecological risk of heavy metals stored in the reservoir sediments has drawn more attention during recent decades. In this study, a total of 10 reservoirs in the western Haihe River basin were sampled. The sediment samples were assessed by the Hakanson potential ecological risk evaluation index. The sediments of upstream and downstream rivers were also sampled for comparative analysis with those of the reservoirs. The results indicated the concentration of Cd was significantly higher than the background value in this region, it was 1.67 times of the background value on average and the highest was 2.77 times. The concentration of Pb was higher than the background value for more than half of the reservoirs. The potential ecological risk was evaluated by the toxic coefficient. The ecological risk level was decreased in the order of Cd>As>Pb>Ni>Cu>Cr>Zn. The ecological risk of Cd in most reservoir sediments belonged to a moderate harm. Xidayang Reservior, which supplied the drinking water for Beijing and Baoding, had the highest level of Cd pollution. The ecological risk of Cd in the upstream and downstream rivers was significantly higher than that of the reservoirs. In addition, the ecological risks of Pb, Cu  and Ni in the upstream rivers were also higher than the reservoirs. The difference of ecological risks of Zn and Cr was not significant between reservoirs and rivers.

 

Retrieval of crown closure of moso bamboo forest using unmanned aerial vehicle (UAV) remotely sensed imagery based on geometricoptical model.

WANG Cong1,2, DU Hua-qiang1,2, ZHOU Guo-mo1,2, XU Xiao-jun1,2, SUN Shao-bo1,2, GAO Guo-long1,2

2015, 26(5):  1501-1509. 

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This research focused on the application of remotely sensed imagery from unmanned aerial vehicle (UAV) with high spatial resolution for the estimation of crown closure of moso bamboo forest based on the geometricoptical model, and analyzed the influence of unconstrained and fully constrained linear spectral mixture analysis (SMA) on the accuracy of the estimated results. The results demonstrated that the combination of UAV remotely sensed imagery and geometricoptical model could, to some degrees, achieve the estimation of crown closure. However, the different SMA methods led to significant differentiation in the estimation accuracy. Compared with unconstrained SMA, the fully constrained linear SMA method resulted in higher accuracy of the estimated values, with the coefficient of determination (R²) of 0.63 at    0.01 level, against the measured values acquired during the field survey. Root mean square error (RMSE) of approximate 0.04 was low, indicating that the usage of fully constrained linear SMA could bring about better results in crown closure estimation, which was closer to the actual condition in moso bamboo forest.

 

Landscape pattern change of Dongzhai Harbour mangrove, South China analyzed with a patch-based method and its driving forces.

HUANG Xing1, XIN Kun2, LI Xiu-zhen1, WANG Xue-ping3, REN Lin-jing1, LI Xi-zhi1, YAN Zhong-zheng1

2015, 26(5):  1510-1518. 

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According to the interpreted results of three satellite images of Dongzhai Harbour obtained in 1988, 1998 and 2009, the changes of landscape pattern and the differences of its driving forces of mangrove forest in Dongzhai Harbour were analyzed with a patchbased method on spatial distribution dynamics. The results showed that the areas of mangrove forest in 1988, 1998 and 2009 were 1809.4, 1738.7 and 1608.2 hm² respectively, which presented a trend of decrease with enhanced degree of landscape fragmentation. The transformations among different landscape types indicated that the mangrove, agricultural land and forest land were mainly changed into builtup land and aquaculture pond. The statistical results obtained from three different methods, i.e., accumulative counting, percentage counting and main transformation route counting, showed that natural factors were the main reason for the changes of patch number, responsible for 58.6%, 72.2% and 72.1% of patch number change, respectively, while the percentages of patch area change induced by human activities were 70.4%, 70.3% and 76.4%， respectively, indicating that human activities were the primary factors of the change of patch areas.

 

Coupling coordination evaluation method between eco-environment quality and economic development level in contiguous special povertystricken areas of China.

WANG Yan-hui1,2,3, LI Jing-yi1,2,3

2015, 26(5):  1519-1530. 

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It is one of the important strategies in the new period of national poverty alleviation and development to maintain the basic balance between the ecological environment and economic development, and to promote the coordinated sustainable development of economy and ecological environment. Taking six contiguous special povertystricken areas as the study areas, a coupling coordination evaluation method between eco-environment quality and economic development level in contiguous special povertystricken areas was explored in this paper. The region’s ecological poverty index system was proposed based on the natural attribute of ecological environment, and the ecological environment quality evaluation method was built up by using AHP weighting method, followed by the design of the coupling coordination evaluation method between the ecological environment indices and the county economic poverty comprehensive indices. The coupling coordination degrees were calculated and their spatial representation differentiations were analyzed respectively at district, province, city, and county scales. Results showed that approximately half of the counties in the study areas achieved the harmoniously coordinated development. However, the ecological environmental quality and the economic development in most counties could not be synchronized, where mountains, rivers and other geographic features existed roughly as a dividing line of the coordinated development types. The phenomena of dislocation between the ecological environment and economic development in state-level poor counties were more serious than those of local poor counties.


 

Interpolation of daily mean temperature by using geographically weighted regressionKriging.

2015, 26(5):  1531-1536. 

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Air temperature is the input variable of numerous models in agriculture, hydrology, climate, and ecology. Currently, in study areas where the terrain is complex, methods taking into account correlation between temperature and environment variables and autocorrelation of regression residual (e.g., regression Kriging, RK) are mainly adopted to interpolate the temperature. However, such methods are based on the global ordinary least squares (OLS) regression technique, without taking into account the spatial nonstationary relationship of  environment variables. Geographically weighted regressionKriging (GWRK) is a kind of method that takes into account spatial nonstationarity
relationship of  environment variables and spatial autocorrelation of regression residuals of environment variables. In this study, according to the results of correlation and stepwise regression analysis, RK1 (covariates only included altitude), GWRK1 (covariates only included altitude), RK2 (covariates included latitude, altitude and closest distance to the seaside) and GWRK2 (covariates included altitude and closest distance to the seaside) were compared to predict the spatial distribution of mean daily air temperature on Hainan Island on December 18, 2013. The prediction accuracy was assessed using the maximum positive error, maximum negative error, mean absolute error and root mean squared error based on the 80 validation sites. The results showed that GWRK1’s four assessment indices were all closest to 0. The fact that RK2 and GWRK2 were worse than RK1 and GWRK1 implied that correlation among covariates reduced model performance.

Landscape character assessment framework in rural area: A case study in Qiaokou, Changsha, China.

ZHANG Qian1, LIU Wen-ping1,2, YU Zhen-rong1

2015, 26(5):  1537-1547. 

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Based on the concept and methods of landscape character assessment (LCA) in England, this paper applied a complete process of landscape character assessment with a case study in Qiaokou Town, which is located in a typical southern paddy fields area in Changsha City. We drew the landscape character map of Qiaokou Town through desk classification and field survey, identified and compared the key characters of each character area, and proposed suggestions on the improvement and stewardship of landscape characters. The results showed that Qiaokou could be divided into 2 landscape character types and 7 landscape character areas with the main differences in cropland and vegetation pattern as well as aesthetic characters. The case study indicated that LCA could be a critical tool to identify the characteristics in rural area, and provide helpful guidance to protect, restore and maintain the unique culture and characters of rural landscape, which is useful for targeted rural landscape development. In the future, we suggested that the assessment on the effects of landscape construction measures on the ecosystem services should be incorporated in LCA research as well.

Fish population structure in the fishway of Changzhou hydrojunction.

TAN Xi-chang1, HUANG He1, TAO Jiang-ping2, LI Si-jia1

2015, 26(5):  1548-1552. 

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The fishway of Changzhou hydrojunction, located in the main stream of Xijiang River, is the biggest fishway in China up to now. Efficiency assessment of the Changzhou fishway is important for fish resource and ecosystem protection of the Pearl River, and can provide basic data for design, construction and management of other fishways in China. A total of 40 fish species in the Changzhou fishway were sampled on 11 occasions from April to June during 2011-2014 by using blocking method. Migratory species such as marbled eel, eel, Fugu ocellatus and the four domestic fish (black carp, grass carp, silver carp and bighead carp) appeared in the fishway. The dominant species included Pelteobagrus vachelli (29.1%), Spualiobarbus curriculus (16.8%), Hemiculter leucisculus (14.7%), Pseudolaubuca sinensis (12.0%), Squalidus argentatus (10.8%), Anguilla japonica (7.3%) and Cirrhinus molitorella (2.7%). Species accumulation curve indicated that up to 61 species would be monitored in the fishway with increasing the sampling frequency, indicating its good passage efficiency. Fish diversity in the Changzhou fishway was significantly lower than that in the downstream in Xijiang River, and two dominant species in the downstream of the Changzhou Dam, Megalobrama hoffmanni and Mystus guttatus, were not monitored in the fishway in this study, revealing that attraction efficiency of the fishway was different for different fish species. The canonical correspondence analysis showed that dam water level was the most important factor for the fishway effectiveness, it was necessary to adjust the operation mode of the Changzhou dam to instigate more fish migration by the fishway. According to the present situation of fishery resources of the Pearl River, it was suggested to include four domestic fish, M. hoffmanni, S. curriculus and  C. molitorella as target species of the Changzhou fishway, and consider more about ecological characteristics of these species.

Screening probiotic endophytic bacteria from medicinal plant Ilex cornuta and the phytopathogeninhibiting effect.

ZHAO Long-fei1, XU Ya-jun1, LAI Xin-he2, KOU Tian-chao1, YAN Jun-li1, ZHOU Pei-pei1, FAN Shan-shan1, YAN Yong-feng1

2015, 26(5):  1553-1562. 

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Culturable endophytic bacteria were isolated from medicinal plant Ilex cornuta by platespreading method, strains with strong inhibitory effect on phytopathogen were screened by confrontation culture and fermentation filtrate culture methods, and the morphological changes of phytopathogen hyphae treated with endophytic bacteria were examined by microscopy and micrograph. Their phylogenetic relationships were determined by homology analysis of the 16S rDNA sequences of PCR products and the taxonomic status of the selected strains was determined based on their morphology, physiology, biochemical test results and 16S rDNA sequence analysis. A total of 85 endophytic bacteria were isolated from the healthy roots, stems, leaves and fruits of I. cornuta, and 10 strains of them showed strong inhibitory effect on Alternaria alternata, Magnaporthe grisea, Fusarium oxysporum, and were preliminarily identified belonging to four genera and seven species. Three strains with the strongest inhibitory effect, GG78 (60.3%), GG31 (48.1%) and GG13 (61.0%) belonged to Enterobacter cloacae, Enterobacter ludwigii and Bacillus cereus, respectively. Microscopic analyses showed that the inhibited phytopathogen hyphae became deformed, distorted, and partially expanded forming plasma concentration and hairlike branch on the hyphae base. These morphological changes could be caused by the extracellular metabolic substances secreted by the endophytic bacteria, such as antibiotics, hydrolytic enzymes, alkaloids and so on.

 

Effects of copper stress on the function of arbuscular mycorrhizal fungi community.

YANG Ru-yi, ZAN Shu-ting, LI Jing, SU Nan-nan, SUN Wen-wen, GUO Fu-yu, ZHOU Gang

2015, 26(5):  1563-1570. 

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The functional differences of arbuscular mycorrhizal fungi (AMF) isolates from different sources have been extensively investigated in the last two decades. However, previous studies were mostly based on individual AMF species and the community level comparison was not addressed properly. Furthermore, many studies did not distinguish the difference between the effects of AMF source and community structure on their function, let alone concerned the significance of host plant. This study evaluated the effects of copper (Cu) stress on AMF community structure and compared the differences of AMF communities from Cu contaminated and uncontaminated substrates on performance of Zea mays  through two shortterm greenhouse pot culture experiments. The results showed that spore abundance and  composition of AMF communities were changed dramatically under Cu stress compared with the control. The communities dominated by Rhizophagus intraradices and Claroideoglomus etunicatum from Cu contaminated soils conferred more benefits on Z. mays in terms of plant growth and physiological properties relative to that from control governed by Funneliformis mosseae.

 

Construction of an indicator system for evaluating the protection efficacy of national nature reserves in China: A case study on terrestrial vertebrates (excluding migratory birds).

YAN Yu-ying1, YANG Dao-de1, DENG Jiao1, ZHANG Zhi-qiang1, ZHOU Xian-yan1, WANG Wei2, LI Jun-sheng2

2015, 26(5):  1571-1578. 

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The protection efficacy of nature reserves is a key element in achieving targets of biodiversity conservation. It is therefore very important to develop a scientific, systematic, and accurate index system for evaluating the protection efficacy of national nature reserves in China. Using methods of frequency statistics, expert consultation, analytic hierarchy process, and demonstration survey, we present a novel index system for evaluating the protection efficacy of Chinese national nature reserves for terrestrial vertebrates (excluding migratory birds) over a 10-year period. The indicator system included one target layer, two system layers, nine factor layers, and forty index layers. The system layer included ecological effectiveness evaluation (with a score of 60%) and management effectiveness evaluation (score of 40%). The ecological effectiveness evaluation was a comprehensive, dynamic evaluation of the target species, population, habitat, and ecological system. The management effectiveness evaluation was focused on the effectiveness of patrol and monitoring. The additional part aimed to analyze the impact of humans on the target species, population and nature resources of the nature reserve. This study combined the ecological effectiveness evaluation and the management effectiveness evaluation for the first time, highlighted the importance of time and space changes, distinguished the influence of natural factors from human factors, and integrated them into the evaluation results. By emphasizing quantifiable indicators, this evaluation index system could vastly assist the protection of nature reserves by improving management effectiveness, biodiversity conservation, and macroscopic decisionmaking.

 

Effects of earthworm on soil microbes and biological fertility: A review.

CAO Jia1,2, WANG Chong1,2, HUANG Yan1,2, JI Ding-ge1,2, LOU Yi1,2

2015, 26(5):  1579-1586. 

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Earthworms are considered as ‘ecosystem engineers’,  as they affect soil microbial community and function by improving micro-habitat, increasing surface area of organic compound, feeding, and transporting microorganisms. Multiscale cavities created through earthworm movements help improve soil porosity and aeration, thus supporting microbial growth and reproduction. Earthworms also break down complex organic compounds into microbeaccessible nutrients by means of feeding on, crushing, and mixing soil. This results in elevated mineralization and improvement of cycling of key soil nutrients including carbon, nitrogen, and phosphorus, overall enhancing the soil biological fertility.

Pothole ecosystem in mountain river: A review.

REN Hai-qing1,2,3, YUAN Xing-zhong1,2,3, LIU Hong3, ZHANG Yue-wei1,2,3, DENG Wei1,2,3, YUE Jun-sheng1,2,3, WANG Xiao-feng1,2,3

2015, 26(5):  1587-1593. 

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The pothole is one of the special habitats in river ecosystems, which is simply structured, welldefined, food chainshort, and easily controlled, thus making it a m〖JP〗odel system in ecological, evolutionary and phenological studies. Here we first reviewed hydrological, chemical and physical characteristics of potholes, their biological community (biodiversity, environmental factors) as well as food chain (competition, predation and parasitism) in mountain rivers. The differences between pothole ecosystems and river ecosystems in hydrological characteristics, biological community and foodchain were analyzed. Hydrological, physical chemical, and ecological characteristics of potholes were largely unexplored in China. Finally, we suggested future directions and recommendations in pothole ecosystems.

Land use and land cover change (LUCC) and landscape service: Evaluation, mapping and modeling.

SONG Zhang-jian, CAO Yu, TAN Yong-zhong, CHEN Xiao-dong, CHEN Xian-peng

2015, 26(5):  1594-1600. 

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Studies on ecosystem service from landscape scale aspect have received increasing attention from researchers all over the world. Compared with ecosystem scale, it should be more suitable to explore the influence of human activities on land use and land cover change (LUCC), and to interpret the mechanisms and processes of sustainable landscape dynamics on landscape scale. Based on comprehensive and systematic analysis of researches on landscape service, this paper firstly discussed basic concepts and classification of landscape service. Then, methods of evaluation, mapping and modeling of landscape service were analyzed and concluded. Finally, future trends for the research on landscape service were proposed. It was put forward that, exploring further connotation and classification system of landscape service, improving methods and quantitative indicators for evaluation, mapping and modelling of landscape service, carrying out longterm integrated researches on landscape patternprocessservicescale relationships and enhancing the applications of theories and methods on landscape economics and landscape ecology are very important fields of the research on landscape service in future.