Table of Content

18 July 2012, Volume 23 Issue 07

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Articles

Responses of Pinus tabulaeformis forest ecosystem in North China to climate change and elevated CO₂: A simulation based on BIOME-BGC model and tree-ring data.

PENG Jun-jie1,2, HE Xing-yuan1, CHEN Zhen-ju1, CUI Ming-xing1,2, ZHANG Xian-liang1,2，ZHOU Chang-hong3

2012, 23(07):  1733-1742. 

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Based on BIOME-BGC model and tree-ring data, a modeling study was conducted to estimate the dynamic changes of the net primary productivity (NPP) of Pinus tabulaeformis forest ecosystem in North China in 1952-2008, and explore the responses of the radial growth and NPP to regional climate warming as well as the dynamics of the NPP in the future climate change scenarios. The simulation results indicated the annual NPP of the P. tabulaeformis ecosystem in 1952-2008 fluctuated from 244.12 to 645.31 g C·m^-2·a^-1, with a mean value of 418.6 g C·m^-2·a^-1. The mean air temperature in May-June and the precipitation from previous August to current July were the main factors limiting the radial growth of P. tabulaeformis and the NPP of P. tabulaeformis ecosystem. In the study period, both the radial growth and the NPP presented a decreasing trend due to the regional warming and drying climate condition. In the future climate scenarios, the NPP would have positive responses to the increase of air temperature, precipitation, and their combination. The elevated CO₂ would benefit the increase of the NPP,and the increment would be about 16.1% due to the CO₂ fertilization. At both ecosystem and regional scales, the treering data would be an ideal proxy to predict the ecosystem dynamic change, and could be used to validate and calibrate the process-based ecosystem models including BIOME-BGC.

Relationships of forest fire with lightning in Daxing’anling Mountains, Northeast China.

LEI Xiao-li1,2, ZHOU Guang-sheng1, JIA Bing-rui1, LI Shuai3

2012, 23(07):  1743-1750. 

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Forest fire is an important factor affecting forest ecosystem succession. Recently, forest fire, especially forest lightning fire, shows an increasing trend under global warming. To study the relationships of forest fire with lightning is essential to accurately predict the forest fire in time.
Daxing’anling Mountains is a region with high frequency of forest lightning fire in China, and an important experiment site to study the relationships of forest fire with lightning. Based on the forest fire records and the corresponding lightning and meteorological observation data in the Mountains from 1966 to 2007, this paper analyzed the relationships of forest fire with lightning in this region. In the period of 1966-2007, both the lightning fire number and the fired forest area in this region increased significantly. The meteorological factors affecting the forest lighting fire were related to temporal scales. At yearly scale, the forest lightning fire was significantly correlated with precipitation, with a correlation coefficient of -0.489; at monthly scale, it had a significant correlation with air temperature, the correlation coefficient being 0.18. The relationship of the forest lightning fire with lightning was also related to temporal scales. At yearly scale, there was no significant correlation between them; at monthly scale, the forest lightning fire was strongly correlated with lightning and affected by precipitation; at daily scale, a positive correlation was observed between forest lightning fire and lightning when the precipitation was less than 5 mm. According to these findings, a fire danger index based on ADTD lightning detection data was established, and a forest lightning fire forecast model was developed. The prediction accuracy of this model for the forest lightning fire in Daxing’anling Mountains in 2005-2007 was >80%.

Water recharge through nighttime stem sap flow of Schima superba in Guangzhou region of Guangdong Province, South China: Affecting factors and contribution to transpiration.

ZHOU Cui-ming1, ZHAO Ping1, NI Guang-yan1, WANG Quan2, ZENG Xiao-ping1, ZHU Li-wei1, CAI Xi-an1

2012, 23(07):  1751-1757. 

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To understand the nighttime water recharge of tree through its sap flow is beneficial to the precise estimation of total transpiration and canopy stomatal conductance, and to the further understanding of the time lag between canopy transpiration and stem sap flow. By using Granier’s thermal dissipation probe, this paper measured the stem sap flow of Schima superba, and synchronously measured the main environmental factors including air temperature, relative humidity, photosynthetically active radiation, and soil moisture content, and also analyzed the water recharge through nighttime stem flow of S. superba at daily and seasonal scales. The sap flow density of S. superba was lower at night than at daytime, and the nighttime sap flow density had a larger variation in dry -season than in wet season. The water recharge at night generally started from sunset when radiation was approaching zero, and lasted up to midnight (18:00-22:00). No significant difference was observed in the nighttime water recharge among seasons, and no significant correlations were found -between the nighttime water recharge and environmental factors, but the nighttime water recharge was well regressed with the diameter at breast height, tree height, tree canopy size, stem biomass, and canopy biomass, suggesting that tree form features and biomass could better explain the nighttime water recharge. The contribution of nighttime water recharge to the total transpiration varied significantly with seasons, and was obviously higher in dry season than in wet season.

Effects of forest gap size and within-gap position on the microclimate in Pinuskoraiensisdominated broadleaved mixed forest.

FENG Jing, DUAN Wen-biao, CHEN Li-xin

2012, 23(07):  1758-1766. 

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HOBO automatic weather stations were installed in the central parts and at the south, north, east, and west edges of large, medium, and small gaps in a Pinus koraiensisdominated broadleaved mixed forest in Xiaoxing’anling Mountains to measure the air temperature, relative humidity, and photosynthetic photon flux density (PPFD) in these locations and the total radiation and precipitation in the gap centres from June to September 2010, taking the closed forest stand and open field as the controls. The differences in the microclimate between various size forest gaps and between the gap centers and their edges as well as the variations of the microclimatic factors over time were analyzed, and the effects of sunny and overcast days on the diurnal variations of the microclimatic factors within forest gaps were compared, aimed to offer basic data and practice reference for gap regeneration and sustainable management of Pinus koraiensisdominated broadleaved mixed forest. The PPFD was decreased in the order of large gap, medium gap, and small gap. For the same gaps, the PPFD in gap centre was greater than that in gap edge. The mean monthly air temperature and total radiation in gap centres were declined in the sequence of July, June, August, and September, and the amplitudes of the two climatic factors were decreased in the order of open field, large gap, medium gap, small gap, and closed forest stand. The mean monthly relative humidityin gap centres dropped in the order of August, July, September, and June, and the amplitude of this climatic factor was decreased in the sequence of closed forest stand, small gap, medium gap, large gap, and open field. The total and monthly precipitations for the three different size gaps and open field during measurement period generally decreased in the order of open field, large gap, medium gap, small gap, and closed forest stand. In sunny days, the variations of PPFD, air temperature, and relative humidity were greater in large gap than in small gap, but in overcast days, it was in opposite.

Variations of canopy temperature in Quercus variabilis plantation and their relations with micrometeorological factors.

WEI Dan-dan1, ZHANG Jin-song1, MENG Ping1, ZHENG Ning1, LI Chun-you2, REN Ying-feng3

2012, 23(07):  1767-1773. 

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Based on the canopy temperature and micrometeorological data of Quercus variabilis in its main growth season (from May to August) in hilly areas of North China in 2011, this paper analyzed the variations of canopy temperature (T_c) in Q. variabilis plantation and their relations with micrometeorological factors in typically clear days and cloudy days. From 9:00 to 17:00 in  clear days, the boundary layer of canopy was unstable, and the mean T_c was 3.55 ℃ higher than the mean air temperature (T_a). In  cloudy days, the variations of T_c were gentler than those in  clear days. The T_c was significantly correlated with T_a, net solar radiation (R_n), relative humidity, and wind speed, with a multiple correlation coefficient being 0.825. The T_a and R_n were the dominant meteorological factors controlling T_c, and their affecting degree on T_c was associated with weather condition.

Spectral characteristics of Pinus tabulaeformis  canopy with different damaged rates of needle leaf in western Liaoning Province, Northeast China.

FENG Rui1, ZHANG YU-shu1, YU Wen-ying1, WU jin-wen1, WANG Pei-juan2, JI Rui-peng1, CHE Yu-sheng3, ZHU Yong-ning3

2012, 23(07):  1774-1780. 

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Through the measurement of the spectral reflectance of large areas Chinese pine (Pinus tabulaeformisCarr.) canopy in western Liaoning Province, this paper analyzed the difference of the spectral reflectance of the canopies with different damaged rates of needle leaf. In visible band, the characteristics of the spectral reflectance of P. tabulaeformis canopies with healthy and damaged needle leaf were in accordance with the spectral characteristics of green plants, but the position of red valley was not obvious when the damaged rate of needle leaf was higher than 60%. In nearinfrared band, with the decrease of the damaged rate of needle leaf, the canopy spectral reflectance increased at 780-1350 nm, but decreased at 1450-1800  and 1950-2350 nm. With the increase of the damaged rate, the position of red-edge inflection moved to the short-wave direction. There were significant correlations between the damaged rate of needle leaf and the red edge feature variables and some vegetation indices. The model based on DVI (1470, 860) could be more reliable for predicting the damaged rate of needle leaf in P. tabulaeformis canopy in western Liaoning Province.

Degradation characteristics of swamps in Zoige Plateau  induced by drainage based on quantitative classification of vegetation.

LI Ke1, YANG Yong-xing1, YANG Yang2, HAN Da-yong1

2012, 23(07):  1781-1789. 

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Based on the field survey of swamp ecological characteristics and environmental quality and the ecological investigation of drained swamp transects in Zoige Plateau of Tibet in 2009, twenty typical swamp plots in the Plateau were classified into three types by TWINSPAN, i.e., primary swamp, long-term drained degraded swamp, and shortterm drained degraded swamp, and each type of the degraded swamps was divided into three degradation grades, i.e., light degradation, moderate degradation, and severe degradation, with the degradation characteristics of vegetation and soil along the swamp degraded gradient studied. The swamp degradation in the Plateau was mainly driven by drainage pattern, drainage intensity, and soil moisture gradient, and the vegetation degradation was more obvious than the soil degradation. In the vegetation degradation, the structural change of hydro-type functional assemblage was most obvious, e.g., the importance value of helophytes under the stress of long-term drainage and short-term drainage decreased from 0.920 to 0.183 and 0.053, while that of mesophytes increased from 0.029 to 0.613 and 0.686, respectively. The soil response to the swamp degradation was in hysteresis, i.e., the soil physical and chemical properties presented definite variations but the differences were not significant among the swamps with different grades of degradation. The results of CCA indicated that soil moisture and nitrogen and potassium contents were the most important factors affecting the plant species distribution in drained degraded swamps in Zoige Plateau.

Effects of NaCl stress on leaf photosynthesis characteristics and free amino acid metabolism of Heyedysarum scoparium.

YAN Hui1, PENG Xiao-bang2, XUE Jian-jie3

2012, 23(07):  1790-1796. 

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This paper studied the variations of leaf photosynthesis gas exchange, chlorophyll fluorescence, and free amino acid contents of Heyedysarum scoparium under the stress of different concentration NaCl, aimed to understand the effects of salt stress on the leaf physiological characteristics and free amino acid metabolism of the plant. Under mild salt stress, the photo-damage of the leaf photosystem II was avoided via the dissipation of excess excitation energy, and stomatal limitation was the main factor reducing the photosynthesis rate. With the increase of salt stress, the leaf photo-protection was not sufficient to avoid oxidative damage, and thus, the damage to photosystem II happened. Under the stress of 200 mmol NaCl·L^-1, non-stomatal limitation was the main factor responsible for the inhibition of photosynthesis. The accumulation and metabolism of major free amino acids in H. scoparium leaves varied under salt stress. Under mild salt stress, the major free amino acids such as proline, glutamate, aspartate, and alanine had a significant accumulation, but with the further increase of salt stress, the aspartate and alanine contents in H. scoparium leaves decreased, while the synthesis and accumulation of praline increased.

Effects of light intensity on the phenotypic plasticity of invasive species Ambrosia trifida.

WANG Rui, SUN Bei, LI Jian-dong, WANG Guo-jiao, SUN Jia-nan, WANG Xin-ruo, ZHONG Ri-ting

2012, 23(07):  1797-1802. 

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Through artificial shading, this paper studied the phenotypic plasticity of invasive species Ambrosia trifida in its morphology, biomass allocation, and photosynthesis characteristics in response to different light intensities. As compared with the control, shading increased the stem height, crown width, leaf area, specific leaf area, and the proportion of leaf biomass in total biomass of A. trifida significantly, but decreased the total biomass, biomass per unit leaf area, and root to shoot ratio. Under natural light condition, the crown width and leaf area were smaller and the root to shoot ratio was larger, which benefited the decrease of water loss under high temperature and high light intensity and manifested the stronger phenotypic plasticity of A. trifida in its morphology and biomass allocation in response to different light intensities. Under shading, the mean daily net photosynthetic rate, transpiration rate, and stomatal conductance decreased, while the stomatal CO₂ concentration increased. At noon when the light intensity was the highest, the photosynthetic rate, transpiration rate, and stomatal conductance under low shading reached the maximum. Under moderate shading and high shading, the chlorophyll content increased significantly, and the chlorophyll a/b had a significant decrease, which could improve the utilization of lightenergy by A. trifida under shading environment.  

Role of mitochondrial alternative oxidase (AOX) pathway in photoprotection in Rumex K-1 leaves.

MENG Xiang-long, ZHANG Li-tao, ZHANG Zi-shan, GAO Hui-yuan, MENG Qing-wei

2012, 23(07):  1803-1808. 

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Taking Rumex K-1 leaves as test materials, this paper studied the role of mitochondrial alternative oxidase (AOX) pathway in photoprotection under different light intensities. Under low light intensity (200 μmol·m^-2·s^-1), and after treated with salicylhydroxamic acid to inhibit the AOX pathway, the leaf actual photochemical efficiency of PSⅡ, linear electron transport rate of photosynthesis, and photosynthetic O₂ evolution rate all decreased significantly while the non Q_B reducing reaction center had a significant increase, indicating that under low light, the photoinhibition was aggravated while the scavenging enzymes of reactive oxygen species (ROS) increased, which avoided the over-accumulation of ROS and partially alleviated the photoinhibition of Rumex K-1 leaves. Under high light intensity (800 μmol·m^-2·s^-1), the inhibition of AOX pathway caused more severe photoinhibition, and the increased activities of ROS scavenging enzymes  were insufficient to prevent the overaccumulation of ROS. This study demonstrated that AOX pathway played an important role in the photoprotection in Rumex K-1 leaves under both high and low light intensities, and the role of AOX pathway in photoprotection under high light could be irreplaceable by the other photoprotection pathways in chloroplast.

Effects of snow pack removal on  soil microbial biomass carbon and nitrogen and the number of soil culturable microorganisms during wintertime in alpine Abies faxoniana forest of western Sichuan, Southwest China.

YANG Yu-lian1, WU Fu-zhong1, HE Zhen-hua2, XU Zhen-feng1, LIU Yang1, YANG Wan-qin1, TAN Bo1

2012, 23(07):  1809-1816. 

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To understand the effects of the lack of snow pack under global warming on the characteristics of soil microorganisms during wintertime, a snow-shading experiment was conducted in a primary fir (Abies faxoniana) forest after snow pack removal, with the soil microbial biomass carbon (MBC) and nitrogen (MBN) and soil culturable microorganisms (bacteria and fungi) at the stages of snow forming, snow covering, and snow melting investigated. Snow pack removal had significant effects on the soil MBC and MBN and the number of soil culturable bacteria and fungi, but the responses of the culturable microorganisms differed with the stages of snow-shading. Under the condition of snow pack removal, the MBC and MBN in soil organic layer decreased significantly at the early stages of snow forming and snow melting but increased significantly at snow covering stage and at the later stage of snow melting, and the number of culturable bacteria decreased significantly from the early stage of snow forming to the stage of snow covering while that of culturable fungi had a significant increase from the early stage of snow forming to the stage of snow melting. After snow melting, the MBC and the number of culturable fungi in soil organic layer had a significant decrease, the number of cultural bacteria was in adverse, but the MBN had less change. The MBC and MBN and the number of culturable microorganisms in soil mineral layer had the similar variation trends as those in soil organic layer, but the fluctuations were smaller. It was suggested that snow pack removal changed the ratio of culturable bacteria to culturable fungi, showing positive effects on the number of soil culturable fungi during wintertime in alpine Abies faxoniana forest of western Sichuan.

Effects of Morus alba and Setaria italica intercropping on their plant growth and diurnal variation of photosynthesis.

ZHU Wen-xu, ZHANG Hui-hui, XU Nan, WANG Peng, WANG Shi-dan, MU Shi-nan, LIANG Ming, SUN Guang-yu

2012, 23(07):  1817-1824. 

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A field investigation was conducted to study the effects of intercropping Morus alba and Setaria italica on their dry matter production, land use efficiency, and diurnal variation of leaf photosynthesis. Under intercropping, the plant height, basal diameter, root length, and branch number of 
 M. alba increased by 6.0%, 13.7%, 6.8%, and 14.8%, respectively, and the leaf yield of M. alba was increased by 31.3%, as compared with monoculture M. alba. In contrast, the plant height and root length of intercropped S. italica had no significant difference with those of monoculture S. italica. Intercropping enhanced the equivalent ratio and use efficiency of arable land. For both M. alba and S. italica in monoculture or intercropping, their leaf photosynthetic depression all occurred at midday (12:00), but the leaf photosynthetic depression of monoculture M. alba was heavier than that of intercropped M. alba. Intercropping promoted the leaf stomatal conductance (g_s) and water use efficiency (WUE)of M. alba at midday, increased the photosynthetic carbon assimilation of M. alba, and inhibited the decline of M. alba leaf actual photochemical efficiency of PSⅡ (Φ_PSⅡ), photosynthetic electron transport rate (ETR), and the maximal photochemical of PSⅡ (F_v/F_m), which might contribute to alleviate the leaf photosynthetic depression of M. alba at midday. It was concluded that M. alba and S. italica intercropping could obviously improve the leaf photosynthetic capacity of M. alba.

Effects of mulberry-soybean intercropping on carbon-metabolic microbial diversity in saline-alkaline soil.

LI Xin, ZHANG Hui-hui, YUE Bing-bing, JIN Wei-wei, XU Nan, ZHU Wen-xu, SUN Guang-yu

2012, 23(07):  1825-1831. 

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Aiming at the characteristics that mulberry-soybean intercropping could alleviate the damage of saline-alkaline soil, Biolog technique was adopted to study the effects of this intercropping on the diversity of carbon-metabolic microbial community in the rhizosphere of saline-alkaline soil. Under mulberry-soybean intercropping, the average well color development (AWCD) symbolizing the metabolic activity of soil microbes was obviously higher, as compared with that under mulberry or soybean monocropping, being the lowest under mulberry monocropping. The McIntosh index was also higher under intercropping than under monocropping, but the Shannon index and Simpson index had less difference between intercropping and monocropping, indicating that intercropping changed the composition and enhanced the diversity of the microbial community in the rhizosphere of saline-alkaline soil. Principal component analysis (PCA) showed that the carbon source utilization mode of the soil microbial community differed between intercropping and monocropping, and the main carbon sources were arbohydrate, carboxylic acid, and polymers. Soil pH and salinity were the main factors limiting the diversity of the microbial community in saline-alkaline soil, and intercropping could effectively decrease the soil pH and salinity and promote the improvement of soil microbial community diversity.

Differences in root developmenly of winter wheat cultivars in Huang-Huai Plain, China.

QIU Xin-qiang, GAO Yang, LI Xin-qiang, HUANG Ling, DUAN Ai-wang

2012, 23(07):  1832-1838. 

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Selecting one presently popularized winter wheat cultivar (Zhengmai 9023)  and  two cultivars (Abo and Fengchan 3) introduced in the 1950s and 1960s in Huang-Huai Plain as test materials, and by using minirhizotron technique, this paper studied the live root length, root diameter distribution, and net root growth rate of the cultivars. Fine roots with a diameter from 0.05 mm to 0.25 mm occupied the majority of the whole root system, and the fine roots with a diameter less than 0.5 mm accounted for 98% of the live root length. The average root diameter varied with plant growth, the variation range being 0.15-0.22 mm, and no significant difference was observed among the cultivars. The live root length was significantly positively correlated root number, suggesting that root number was the main factor for the increase of live root length. The most vigorous growth period of the roots was from reviving to jointing stage, and Abo and Fengchan 3 had a longer period increased root vitality, as compared with Zhengmai 9023. For Zhengmai 9023, its fine roots with a diameter more than 0.1 mm had an increasing proportion after jointing stage, which was helpful for improving plant resistance, root activity, and grain-filling at late growth stages.minirhizotron;

Effects of planting density on  root spatiotemporal distribution and plant nitrogen use efficiency of winter wheat.

WANG Shu-li, HE Ming-rong, DAI Xing-long, ZHOU Xiao-hu

2012, 23(07):  1839-1845. 

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Taking winter wheat cultivars Tainong 18 (TN18) and Shannong 15 (SN15) as test materials, a field experiment was conducted to study the effects of planting density (135×10⁴, 270×10⁴, and 405×10⁴ plants·hm^-2 for TN18; 172.5×10⁴, 345×10⁴, and 517.5 ×10⁴ plants·hm^-2 for SN15) on the root spatiotemporal distribution and plant nitrogen use efficiency of the varieties. For TN18, its root length density, total root absorbing area, and active root absorbing area increased with increasing planting density, and peaked at planting density 405×10⁴ plants·hm^-2 during the whole growth period. For SN15, its root length density, total root absorbing area, and active root absorbing area achieved the highest values at planting density 345×10⁴ plants·hm^-2 at booting and late grain-filling stages. The grain yield, nitrogen uptake efficiency, nitrogen partial factor productivity, and nitrogen use efficiency of TN18 were the highest at planting density 405×10⁴ plants·hm^-2, and those of SN were the highest at planting density 345×10⁴ plants·hm^-2 but had less differences between the densities 345×10⁴ and 517.5×10⁴ plants·hm^-2. The inorganic nitrogen accumulation in different soil layers decreased with increasing planting density at maturity stage. Taking grain yield and nitrogen use efficiency into consideration, the appropriate planting density of TN18 and SN15 would be 405×10⁴ and 345×10⁴ plants·hm^-2, respectively.

Dynamic changes of photosynthetic characteristics in big-spike wheat yield formation.

WANG Li-fang, XU Xuan-bin, WANG De-xuan, SHANGGUAN Zhou-ping

2012, 23(07):  1846-1852. 

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A field experiment was conducted to investigate the yield traits, leaf photosynthetic rate, chlorophyll fluorescence parameters, chlorophyll content （Chl）, and leaf area index (LAI) of eight new big-spike wheat lines, with multiple-spike cultivar Xinong 979 (Triticum aestivum cv. Xinong 979) as the control. The eight new lines had significantly higher kernel numbers per spike, kernel qualities, and 1000grain mass but lower spike numbers per unit area, and the lines 2036, 2037, 2038, and 2040 had significantly higher yields than the control. The average net photosynthetic rate (P_n) of the eight new lines had no significant difference with that of the control, but the PSⅡ maximum energy conversion efficiency, PSⅡ actual photochemical efficiency, photochemical quenching coefficient, and PSⅡ reaction center activity of the lines were higher than those of the control. The leaf Chl of the lines 2037, 2040, 2039, 2038 and 2036 were 17.5%, 19.1%, 15.3%, 13.9%, and 7.9% higher than those of the control, and their LAI was significantly higher than that of the control and declined slowly in late growth period.

Effects of seeding-box total fertilization on rice yield and nitrogen loss.

LIU Ru-liang1,2, LI You-hong2, ZHANG Ai-ping1, WANG Fang2, ZHAO Tian-cheng2, CHEN Chen2, HONG Yu2, YANG Zheng-li1

2012, 23(07):  1853-1860. 

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By using seeding-box total fertilization technology, a two-year field plot experiment was conducted to study the effects of applying medium rate of controlledrelease urea fertilizer (MN, 80 kg N·hm^-2), high rate of controlled-release urea fertilizer (HN, 120 kg N·hm^-2), and conventional urea fertilizer (FP, 300 kg N·hm^-2) on rice yield and nitrogen loss. As compared with FP, HN did not decrease rice yield significantly, and MN and HN increased the two-year average nitrogen use efficiency (NUE) by 26.2% and 20.7%, respectively (the NUE in treatment FP was 33.2%). In treatment FP, the total N concentration in surface water peaked after 1-3 days of urea application; while in treatments MN and HN, the total N concentration in surfate water peaked after 7-9 days of urea application, and was significantly lower than that in treatment FP throughout the rice growth period. The nitrogen leaching loss in treatment FP mainly occurred at tillering stage, while that in treatments MN and HN delayed to tilleringflowering stage. In all treatments, the NO₃^--N loss accounted for 59.7%-64.2% of the total N loss. HN decreased the total N leaching loss by 51.8%, as compared with FP.

Effects of plant polysaccharide compound agents on the photosynthetic characteristics and dry matter of soybean.

BAI Wen-bo1, SONG Ji-qing1, GUO Jin-yi2, LIU Xing-hai1, LI Ji-hui1

2012, 23(07):  1861-1868. 

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A field experiment was conducted to study the effects of foliar spraying three compound agents ［plant polysaccharides (P₁), plant polysaccharides and 5-aminolevulinic acid (P₂), and plant polysaccharides and 5-aminolevulinic acid and dimethylpiperidinium chloride (P₃)］ at the initial flowering stage of soybean on its leaf chlorophyll content, photosynthesis and transpiration, dry matter accumulation and allocation, and grain yield. Within 35 days after spraying the three compound agents, the leaf chlorophyll content had obvious increase, and its decreasing trend with plant growth had somewhat delay. Compared with the control, spraying P₁ and P₃ increased the leaf photosynthetic rate and water use efficiency by more than 13.2% and 10.3%, respectively. With the spraying of the three compound agents, the dry matter accumulation in aerial part increased, and the allocation of dry matter from leaf to pod was also enhanced, with the contribution of postanthesis assimilates to grain yield increased by more than 17.1%. The 100-grain mass and the pods and seeds per plant increased significantly after spraying P₁ and P₃, but had no significant increase after spraying P₂. The grain yield of soybean treated with the three compound agents increased by more than 5.9%, compared with the control. This study showed that the three plant polysaccharide compound agents could increase the leaf chlorophyll content, delay the leaf-senescence, improve the leaf photosynthetic capacity and water status, effectively control the dry matter accumulation and post-anthesis assimilates allocation, and increase the grain yield of soybean.  

Greenhouse tomato transpiration and its affecting factors: Correlation analysis and model simulation.

YAO Yong-zhe1, LI Jian-ming1, ZHANG Rong2, SUN San-jie1, CHEN Kai-li1

2012, 23(07):  1869-1874. 

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A pot experiment was conducted to study the correlations between the daily transpiration of greenhouse tomato and the related affecting factors such as total leaf area per plant, soil relative moisture content, air temperature, relative humidity, and solar radiation under different treatments of supplementary irrigation. A regression model for the daily transpiration of greenhouse tomato was established. There existed significant linear correlations between the daily transpiration and the test affecting factors, and the affecting factors had complicated mutual effects. Soil relative moisture content was the main decision factor of the transpiration, with the decision coefficient being 27.4%, and daily minimum relative humidity was the main limiting factor, with the decision coefficient being -119.7%. The square value of the regression coefficient (R²) between the predicted and measured tomato daily transpiration was 0.81, root mean squared error (RMSE) was 68.52 g, and relative prediction error (RE) was 19.4%, suggesting that the regression model established by using the main affecting factors selected through path analysis could better simulate the daily transpiration of greenhouse tomato.

Characteristics and adaption of seasonal drought in southern China under the background of global climate change. Ⅰ. Change characteristics of precipitation resource.

SUI Yue1,2, HUANG Wan-hua1,3, YANG Xiao-guang1, LI Mao-song4

2012, 23(07):  1875-1882. 

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Based on the 1959-2008 precipitation data from 262 meteorological stations in southern China, this paper analyzed the change characteristics of seasonal precipitation trend coefficient, precipitation variability, and annual and decadal precipitation standardized anomalies in this region. In the study period, there was a great difference among the  trend of quarter precipitation. In most parts of the region, the precipitation in spring and autumn presented a decreasing trend but that in summer and winter was in adverse; only in southwest part, a slightly different trend was observed. In the whole region, the probability of spring drought decreased, but that of summer drought, autumn drought, and winter drought increased. Spring drought often occurred in south and southwest parts, summer drought and autumn drought often occurred in south part and the middle, lower reaches of Yangtze River, and winter drought  expanded from south part to south part and the middle, lower reaches of Yangtze River. The precipitation in spring and autumn was below the normal level after the 1980s, while that in summer and winter was below the normal level before the 1990s, above the normal level in the 1990s, and below the normal level since the 21st century. The decadal change of the seasonal precipitation standardized anomaly in each part of the region was basically consistent, i.e., decreased in autumn and increased in summer and winter.

New paradigm for soil and water conservation: A method based on watershed process modeling and scenario analysis.

ZHU A-xing1,2, CHEN La-jiao1,3, QIN Cheng-zhi1, WANG Ping1, LIU Jun-zhi1,3, LI Run-kui3, CAI Qiang-guo1

2012, 23(07):  1883-1890. 

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With the increase of severe soil erosion problem, soil and water conservation has become an urgent concern for sustainable development. Small watershed experimental observation is the traditional paradigm for soil and water control. However, the establishment of experimental watershed usually takes long time, and has the limitations of poor repeatability and high cost. Moreover, the popularization of the results from the experimental watershed is limited for other areas due to the differences in watershed conditions. Therefore, it is not sufficient to completely rely on this old paradigm for soil and water loss control. Recently, scenario analysis based on watershed modeling has been introduced into watershed management, which can provide information about the effectiveness of different management practices based on the quantitative simulation of watershed processes. Because of its merits such as low cost, short period, and high repeatability, scenario analysis shows great potential in aiding the development of watershed management strategy. This paper elaborated a new paradigm using watershed modeling and scenario analysis for soil and water conservation, illustrated this new paradigm through two cases for practical watershed management, and explored the future development of this new soil and water conservation paradigm.

Improvement of “scatter degree” method and its application in evaluating river ecosystem health.

SONG Gang-fu1,2, SHEN Bing1

2012, 23(07):  1891-1896. 

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“Scatter degree” method is generally blamed for not capable of reflecting the subjective information of evaluator in comprehensive evaluation and for the complexity, uncertainty, and variety of the factors affecting river ecosystem health. In this paper, the “scatter degree” method was improved and applied to comprehensively evaluate the ecosystem health status of the upstream, midstream, and downstream of Beiyunhe River which flowed through Beijing and Tianjing. The ecosystem health value of upstream, midstream, and downstream was evaluated as 0.539, 0.521 and 0.546, respectively, indicating that these streams were in subhealth condition. The environmental status of flowing water was the most important factor affecting the River’s ecosystem health. With the application of the improved method to evaluate river ecosystem health, both the evaluator’s subjective judgment and the data’s objective information could be included, the evaluation process was transparent, and the evaluation results were scientific, reasonable, objective, and reliable, suggesting that this method could be served as a technical support and a basis for the comprehensive treatment of rivers.

Spatiotemporal variation of vegetation in northern Shaanxi of Northwest China based on SPOT-VGT NDVI.

YANG Yan-zheng1, ZHAO Peng-xiang1, HAO Hong-ke1, CHANG Ming2

2012, 23(07):  1897-1903. 

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By using 1998-2010 SPOT-VGT NDVI images, this paper analyzed the spatiotemporal variation of vegetation in northern Shaanxi. In 1998-2010, the NDVI in northern Shaanxi had an obvious seasonal variation. The average monthly NDVI was the minimum (0.14) in January and the maximum (0.46) in August, with a mean value of 0.28. The average annual NDVI presented an overall increasing trend, indicating that the vegetation in this area was in restoring. Spatially, the restoration of vegetation in this area was concentrated in central south part, and the degradation mainly occurred in the north of the Great Wall. Air temperature and precipitation were the important climate factors affecting the variation of vegetation, with the linear correlation coefficients to NDVI being 0.72 and 0.58, respectively. The regions with better restored vegetation were mainly on the slopes of 15°-25°, indicating that the Program of Conversion of Cropland to Forestland and Grassland had a favorable effect in the vegetation restoration in northern Shaanxi.

Secondary productivity of macrobenthos in intertidal flat of Luoyuan Bay, Fujian Province of East China.

DU Yong-fen1, GAO Shu1, YU Zi-shan2, WANG Dan-dan1, RAN Qi1

2012, 23(07):  1904-1912. 

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Based on the survey data of macrobenthos in the intertidal flat of Luoyuan Bay in 2009, and by using Brey’s empirical formula, this paper estimated the macrobenthos secondary productivity, production/biomass (P/B) ratio, and their spatiotemporal distribution patterns in the flat. The annual secondary productivity and P/B ratio of the macrobenthos in the flat were estimated as 18.58 g AFDM （ash free dry mass）·m^-2 ·a^-1 and 0.97, respectively, and the secondary productivity in the Spartina alterniflora marshes of the upper intertidal flat (8.97g AFDM·m^-2· a^-1) was much lower than that in the bare flat of the lower intertidal zone (28.19 g AFDM·m^-2·a^-1). Since the introduction of S. alterniflora by the end of the 1980s, the secondary productivity of the macrobenthos in the flat had increased about 4 folds.  Musculus senhousei, which  inhabited in the lower bare flat, contributed 66.4% of the total macrobenthos secondary productivity in the entire intertidal flat. If the contribution from M. senhousei was not taken into account, the macrobenthos secondary productivity in the salt marshes would be significantly higher than that in the bare flat, and the macrobenthos secondary productivity in the intertidal flat would have less change. The successful colonization of M. senhousei was partly attributed to the changes of sediment composition enhanced by S. alterniflora due to its capability in trapping fine-grained materials; this species’ feeding activities result in a remarkable increase of sediment chlorophyll a content. There was a significant positive correlation between the secondary productivity of macrobenthos and the sediment chlorophyll a and/or organic matter contents. These findings suggested that salt marshes had effects on the coastal wetland ecosystem via a number of physical and biological mechanisms.  

Physiological responses of Enteromorpha linza and Enteromorpha prolifera to seawater salinity stress.

GAO Bing-bing1, ZHENG Chun-fang2, XU Jun-tian3, ZHENG Qing-song1, LIU Zhao-pu1, ZHAI Rui-ting1, JIANG He-ping1

2012, 23(07):  1913-1920. 

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To investigate the physiological responses and adaptation mechanisms of Enteromorpha to seawater salinity stress, a laboratory experiment with Enteromorpha linza and E. prolifera was conducted to study their fresh mass (FM), relative growth rate (RGR), relative electrical conductivity (REC), chlorophyll (Chl) and carotenoid (Car) contents, Chl a/Chl b, Chl/Car, chlorophyll fluorescence parameters, and osmotic adjustment ability (OAA) under the stress of different salinity levels of diluted and concentrated seawater for 10 days. Compared with the control, 10%-200% salinity seawater increased the FM and RGR of the two Enteromorpha species obviously, 100% and 50% salinity seawater made the FM and RGR of E. linza and E. prolifera peaked, respectively, while 300% salinity seawater decreased the FM and RGR of E. linza and E. prolifera significantly, with the decrement being larger for E. linza. The biomass of E. linza and E. prolifer only had an increase in 50% and 100% sanity seawater and in 10%, 50%, 100%, and 200% salinity seawater, respectively. The Chl and Car contents and Chl a/Chl b of E. linza and E. prolifera had a significant increase in 10% salinity seawater, but decreased after an initial increase with the increasing salinity level of seawater. The Chl and Car contents and Chl a/Chl b of E. linza and E. prolifera peaked in 100% and 50% salinity seawater, respectively. With increasing salinity of seawater, the light use efficiency (α), maximal photochemical efficiency of PSⅡ(F_v/F_m), actual photochemical efficiency of PSⅡ in the light (Yield), maximal relative electron transport rate (rETR_max), and halfsaturation light intensity (I_k) of E. linza and E. prolifera all showed the same variation trend as Chl. 10%-300% salinity seawater enabled E. linza and E. prolifera to express certain osmotic adjustment ability (OAA), and the OAA of E. linza and E. prolifer peaked in 100% and 50% salinity seawater, respectively.  The growth of Enteromorpha had no correlation with Chl/Car, but was significantly negatively correlated with REC and positively correlated with Chl, Car, Chl a/Chl b, F_v/F_m, Yield, rETR_max, α, I_k, and OAA. To sum up, 100% salinity was the optimal salt concentration for the growth of E. linza, and 50% salinity was optimal for E. prolifera. E. prolifera could adapt to a wider range of salinity than E. linza. The parameters REC, Chl, Car, Chl a/Chl b, F_v/F_m, Yield, rETR_max, α, I_k, and OAA could be used to evaluate the salt adaptation of Enteromorpha.

Microbial biomass and its correlations with carbon, nitrogen, and phosphorus in the sediments of Taihu Lake.

WANG Na1, XU De-lin1, GUO Xuan2, WU Xiao-qing1, AN Shu-qing1

2012, 23(07):  1921-1926. 

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To explore the responses and feedbacks of the microbes in the sediments of Taihu Lake to the sediment nutrients, an investigation was made on the microbial biomass carbon (MB-C), microbial biomass nitrogen (MB-N), microbial biomass phosphorus (MB-P), and their correlations with the total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) in the sediments. The microbial biomass in the sediments was 184.66 mg·kg^-1, being higher at the lakeside than in the midlake region. The MB-C was higher in the western coastal region, Zhushan Bay, and Meiliang Bay, with an average of 127.57 mg·kg^-1, MB-N was higher in Meiliang Bay, Gonghu Bay, midlake region close to Meiliang Bay and Gonghu Bay, and eastern costal region,  with an average of 19.25 mg·kg^-1, and MB-P was higher in the eastern region and parts of the midlake region, with an average was 19.09 mg·kg^-1. The TOC high value zone (≥2.30 g·kg^-1) was mainly in Zhushan Bay, western coastal region, Meiliang Bay, and Gonghu Bay, with an average of 1.59 g·kg^-1, TN high value zone (≥0.30 g·kg^-1) was mainly in the Gonghu Bay, Meiliang Bay, Zhushan Bay, and western costal region, with an average of 0.21 g·kg^-1, and TP high value zone
(≥1.20 g·kg^-1) was mainly in the eastern coastal region and parts of the mid-lake region, with an average of 0.55 g·kg^-1. The TOC/TN ratio in the sediments was 7-19, with an average of 8.97, which showed that the organic substances in the sediments had obvious dual sources, among which, terrestrial organisms were mainly in the west side of the lake. The microbial biomass in the sediments was significantly positively correlated with sediment TOC and TN but had less correlation with sediment TP, and the MB-C/MB-N was significantly correlated with sediment TOC/TN, suggesting that the microbes in the sediments of Taihu Lake were mainly affected by the sediment TOC and TN, and the changes of the TOC/TN had significant effects on the microbial community structure.

Effects of temperature on population parameters of Therioaphis trifolii (Monell) (Homoptera: Aphididae).

LIU Chang-zhong, DU Jun-li, ZHANG Ting-wei, QIAN Xiu-juan, CHEN Ying-wu

2012, 23(07):  1927-1932. 

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To investigate the effects of temperature on the population growth of Therioaphis trifolii (Monell) (Homoptera: Aphididae), a laboratory experiment was conducted to study the development, reproduction, and life table of the spotted alfalfa aphid at nine constant temperatures ranged from 15 to 35 ℃. The aphid could not survive at 35 ℃.The total nymphal period shortened significantly with increasing temperature. From birth to adult stage, it required 18.33 days at 15 ℃, but only 4.02 days at 32 ℃. The survivorship of the nymphs ranged from 40.0% （32 ℃） to 83.6% （25 ℃）.  The average longevity of the adults ranged from 10.64 days at 32 ℃ to 20.87 days at 23 ℃. The reproductive peak was advanced with increasing temperature, and the reproduction duration at all test temperatures was 3-6 days except that at 15 ℃ (15 days). The average fecundity and the highest fecundity were the highest at 25 ℃, being 82.0 and 149.0 offspring per female aphid, respectively. When the temperature increased, the mean generation time  was gradually decreased from 31.17 days at 15 ℃ to 10.17 days at 32 ℃. The net reproductive rate  was the highest (6862) at 25 ℃ and the lowest (13.96) at 32 ℃. The intrinsic rate of increase  was 0.10-0.30 per day, with the highest at 28 ℃ but the lowest at 15 ℃. The developmental threshold temperature and thermal constant of the nymphs were 9.35 ℃ and 97.83 daydegrees, respectively. Unary quadratic equation could be used to describe the relationships of the fecundity, net reproductive rate, and intrinsic growth rate with the temperature.

Resistance mechanisms and cross-resistance of phoximresistant Frankliniella occidentalis Pergande population.

WANG Sheng-yin1, 2, ZHOU Xian-hong1, ZHANG An-sheng1, LI Li-li1, MEN Xing-yuan1, ZHANG Si-cong1， LIU Yong-jie2, YU Yi1

2012, 23(07):  1933-1939. 

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To understand the resistance risks of Frankliniella occidentalis Pergande against phoxim, this paper studied the resistance mechanisms of phoximresistant F. occidentalis population against phoxim and the cross-resistance of the population against other insecticides. The phoxim-resistant population had medium level cross-resistance to chlorpyrifos, lambda-cyhalothrin, and methomyl, low level cross-resistance to chlorfenapyr, imidacloprid, emamectinbenzoate, and spinosad, but no crossresistance to acetamiprid and abamectin. The synergists piperonyl butoxide (PBO), s,s,s-tributyl phosphorotrithioate (DEF), and triphenyl phosphate (TPP) had significant synergism (P<0.05) on the toxicity of phoxim to the resistant (XK), field (BJ), and susceptible (S) populations, while diethyl maleate (DEM) had no significant synergism to XK and S populations but had significant synergism to BJ population. As compared with S population, the XK and BJ populations had significantly increased activities of mixed-functional oxidases P₄₅₀ (2.79-fold and 1.48-fold), b₅ (2.88-fold and 1.88-fold), O-demethylase (2.60-fold and 1.68-fold), and carboxylesterase (2.02-fold and 1.61-fold, respectively), and XK population had a significantly increased acetylcholine esterase activity (3.10-fold). Both XK and BJ population had an increased activity of glutathione S-transferases (1.11-fold and 1.20-fold, respectively), but the increment was not significant. The increased detoxification enzymes activities in F. occidentalis could play an important role in the resistance of the plant against phoxim.  

Effects of wheatoilseed rape intercropping and methyl salicylate application on the spatial distributions of Sitobion avenae and its main natural enemies

DONG Jie, LIU Ying-jie, WANG Guang, LIU Yong

2012, 23(07):  1940-1944. 

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A field investigation was conducted on the spatial distributions of Sitobion avenae and its main natural enemies under wheatoilseed rape intercropping and methyl salicylate application. With the development of wheat plant, an alternation from aggregation to uniform was observed in the spatial distribution of S. avenae under the intercropping and methyl salicylate application, being more obvious under the interaction of the two practices. The spatial distribution of S. avenae natural enemies was in accordance with that of the aphid. These results could be used for the reference of sampling investigation and forecast of wheat aphid and its natural enemies in field.  

Effects of fermented cattle dung on the growth and development of Tenebrio molitor larvae.

ZENG Xiang-wei1, WANG Xia2, GUO Li-yue1, ZHAN Li-jie1, BO Wen-jing3, LI Zhan1, WU Guang-lei1, JIANG Gao-ming1,3

2012, 23(07):  1945-1951. 

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In order to make use of and industrialize the animal dung from large cattle farms, this paper explored the feasibility of using Tenebrio molitor to digest and utilize cattle dung. Cattle dung was mixed with the conventional feed (65% wheat bran, 30% corn flour, and 5% bean pulp) of T. molitor in definite roportions, and fermented with effective microorganisms (EM). The fermented products containing 60% and 80% of cattle dung (FD₁ and FD₂, respectively) were selected to feed T. molitor larvae, and the effects of the fermented products on the growth curve, death rate, pupation rate, and antioxidant system of the larvae were compared. Compared with CK (conventional deed), the FD₁ made the developmental duration of the larvae prolonged by 10 days and the larvae’s death rate upraised somewhat, but made the single larva’s total food intake, average body mass, crude fat content, and ratio of unsaturated to saturated fat acids increased by 49%, 28%, 26%, and 32%, respectively (P<0.05), and the activity of larvae’s antioxidant system improved significantly, showing a remarkable adaptability of the larvae to FD₁. Unlike FD₁, FD₂ displayed definite disadvantages in most test growth indicators, as compared with CK, indicating that T. molitor larvae had weak adaptability to FD2. Our findings suggested that using FD₁ to feed the 3rd instar of T. molitor larvae would have good practical prospects in industrializing cattle dung.

Effects of soybean trypsinase inhibitor and defense signaling compounds on detoxificationenzymes in Spodoptera litura(F.) larvae.

WU Guo-zhao1,2,3, HU Lin1,2,3, YE Mao1,2,3, WANG Rui-long1,2,3, ZHU Ke-yan4, ZENG Ren-sen1,2,3， CAI Wen5

2012, 23(07):  1952-1958. 

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In a long history of interactions between insects and plants, plants have developed various anti-insect compounds and defense signaling transduction pathways to defend against herbivorousinsects, while insects have responded with sophisticated detoxification enzyme systems to protect against the toxicity of antiinsect compounds. In this study, the 2nd or 3rd instar of Spodoptera litura larvae were successively fed with the diets containing 0.5% soybean trypsinase inhibitor (SBTI) for six generations to evaluate the effects of SBTI and defense signaling compounds on the activities of detoxification enzymes carboxylesterase (CarE) and glutathione-S-transferase (GST) in the midgut and fatbody of the larvae. After fed with the diets, the CarE and GST activities in the 5th instar larvae increased significantly. The CarE activity in the midgut and fatbody of the second generation larvae was the highest, being 2.06 and 2.40 times, and 1.96 and 2.70 times of that of the control, and the GST activity in the midgut and fatbody of the  fourth and second generations was the highest, being 7.03 and 11.58 times, and 5.71 and 3.60 times of that of the control, respectively. These induced enzyme activities decreased gradually when the larvae continuously grew with the SBTIcontaining diets. In addition, when the S. litura larvae were preexposed to methyl jasmonate (MeJA) or methyl salicylate (MeSA) for 48 h or fed with the diets containing 0.5% SBTI, the activities of CarE and GST in the midgut and fatbody increased significantly, and, when the 2nd instar larvae were pre-exposed to MeJA and MeSA for 48 h, the effects of SBTI on the GST activity in larval midgut and fatbody were reduced.

Effects of population density and culture volume on the growth and reproduction of Moina irrasa. 

CHEN Li-na, LI Yu-ying, DENG Dao-gui, JIN Xian-wen, GE Qian, WANG Shao-qin

2012, 23(07):  1959-1964. 

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A laboratory experiment was conducted to study the effects of different population density (D₁: 100 ind·L^-1, D₂: 150 ind· L^-1, D₃: 300 ind·L^-1) and culture volume (V₁: 50 mL, V₂: 100 mL, V₃: 400 mL) on the growth and reproduction of Moina irrasa at 25 ℃. At the same culture density, the body length of the M. irrasa females at their first pregnancy, the first brood, and the total offsprings per female decreased with the increase of culture volumes, while the sex ratio (male/female) of the offsprings was in adverse. At the same culture volumes, the total offsprings per female decreased with the increase of culture density. At D₁V₁, the body length of the females at their first pregnancy (095±010 mm) and the total offsprings (171.3±19.8 ind) per female were the maximum.  At D₃V₂, the sex ratio was the maximum (0.54±0.05). Culture density, culture volume, and their interactions significantly affected the total offsprings per female and the sex ratio (P<0.001).

Cadmium bioaccumulation and its toxicity in Babylonia areolata under different nutritional status.

XUE Ming1,2, KE Cai-huan2

2012, 23(07):  1965-1972. 

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An indoor exposure experiment with juvenile Babylonia areolata was conducted to study its survival, growth, cadmium (Cd) accumulation, metallothionein (MT) induction, and glycogen content as well as the DNA integrity of hepatopancreas tissue. The juveniles were starved or fed with mussel (Perna viridis) or clamworm (Perinereis aibuhitensis), and exposed to 50 μg·L^-1 of Cd²⁺  for 10 weeks. Prolonged starvation and simultaneous exposure to Cd reduced the survival rate of  B. areolata, and its glycogen was mobilized in great extent. Feeding with P. viridis or P. aibuhitensis helped the B. areolata to combat Cd toxicity and lessen mortality. After exposed to Cd, the damage of the DNA integrity of hepatopancreas tissue for the B. areolata fed with P. viridis or P. aibuhitensis could be recovered with time, but not for the starved B. areolata. Prolonged starvation caused tissue atrophy and led to Cd accumulation and MT increase, while feeding with P. viridis or P. aibuhitensis increased the B. areolata mass and lowered the Cd accumulation and MT level because of the tissue dilution effect. The B. areolata fed with P. viridis had better growth and lower Cd content than that fed with P. aibuhitensis. This study indicated that starvation intensified the toxicity of Cd to B. areolata, while prey type had significant effects on the growth rate of the B. areolata and indirectly affected its Cd accumulation, MT induction, and glycogen consumption. It was suggested that when using gastropods such as B. areolata as the indicator species to monitor marine environmental pollution,  it would be necessary to consider the effects of habitat ecological data including food richness and prey type. Moreover, in the highdensity cultivation of B. areolata in factory, rational feeding and periodic measurement of Cd concentration in seawater should be made.

Construction of suppression subtractive hybridization (SSH) library of copepod Pseudodiaptomous annandalei and its ferritin cDNA cloning and differential expression under nickel stress.

JIANG Jie-lan, WANG Gui-zhong, WU Li-sheng, LI Shao-jing

2012, 23(07):  1973-1978. 

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To study the molecular response mechanisms of copepod to nickel stress, a suppression subtractive hybridization (SSH) cDNA library of Pseudodiaptomous annandalei under nickel stress was constructed by using SSH technique, and a total of 140 clones were randomly picked from the growing colonies and identified by PCR. The recombinant rate of the library was 98.6%, and the volume of the library was 1.12×10⁶ cfu. After the recombinant plasmids were sequenced, a partial cDNA fragment of ferritin was recognized based on BLAST searches in NCBI, with a size of 859 bp and  continuously encoding 170 amino acid residues. The semi-quantitative PCR results showed that the ferritin cDNA under 24 h nickel stress was distinctly up-regulated. The successful construction of the SSH library and the obtaining of ferritin cDNA fragment would supply basis for the further study of the molecular response mechanisms of copepod to nickel stress.

Isolation and identification of aerobic denitrifying bacterium Defluvibacter lusatiensis strain DN7 and its heterotrophic nitrification ability.

XIAO Ji-bo, JIANG Hui-xia, CHU Shu-yi

2012, 23(07):  1979-1984. 

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An aerobic denitrifying bacterium strain DN7 with excellent nitrate removal ability was isolated from the biocontact oxidation reactor treating bamboo process wastewater. The strain had a nitrate removal efficiency of 99.4% in 72 h. Cell microscopic observation demonstrated that the strain was a gramnegative bacillus with an average size of 0.5 μm×1.5 μm, and the colony was ivory. Based on its biochemical/morphological characteristics and its 16S rDNA sequence homologic analysis, this strain was identified as Defluvibacter lusatiensis. Its optimal carbon sources were small molecular organic compounds such as sodium citrate and glucose, and its nitrogen removal efficiency reached 99.0% when the medium C/N ratio was 9. The nitrogen removal efficiency could reach more than 96% when the nitrate concentration was below 138.48 mg·L^-1 and the nitrite concentration was lower than 1.0 mg·L^-1. The strain was not sensitive to DO, and the denitrification was favored under neutral or a bit alkaline condition. The DN7 also had good ability in degrading ammonim nitrogen, with the removal efficiency being 84.7% in 72 h.

Phylogenic diversity of soil chemotatic bacteria in a phosphorous-rich area around Dianchi Lake of Yunnan Province, Southwest China.

2012, 23(07):  1985-1991. 

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Phosphate-solubilizing bacteria (PSB) were isolated from 100 soil samples collected from a phosphorous-rich area around the Dianchi Lake of Yunnan Province, Southwest China. The chemotatic PSB strains were screened by cheA gene detection, and their chemotaxis was verified by the method of soft agar plate. The tricalcium phosphate (TCP)solubilizing activities of PSB were determined with molybdenum blue spectrophotometry. Based on 16S rRNA sequences, the phylogenic relationships of the PSB were analyzed. A total of 145 PSB strains with a diameter of phosphatesolubilizing halo zone ranged from 0.5 cm to 2 cm were isolated, among which, 37 strains were chemotactic. The 37 chemotactic strains showed chemotaxis towards four test attractants, and exhibited TCPsolubilizing activity. Phylogenic analysis revealed that the 37 chemotatic strains were belonged to 17 species of 10 genera, in which, Pseudomonas was dominant (9 strains of 5 species), followed by Enterobacter (8 strains of 3 species). Only one species (Bacillus aryabhattai) was isolated from Bacillus, but 9 strains were identified.

Effects of enhanced UV-B radiation on terrestrial ecosystem carbon cycle: A review.

LIU Shu-rong, HU Rong-gui, CAI Gao-chao

2012, 23(07):  1992-1998. 

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As one of the most important phenomena of global climate change, the enhancement of ultraviolet B radiation (UV-B, 280-320 nm) could have critical impact on the carbon cycle in terrestrial ecosystem. Through the impacts on plant photosynthesis, litter decomposition, and soil respiration, the enhanced UV-B radiation can affect the carbon input, turnover, and output of terrestrial ecosystem. Other climatic factors (ambient CO₂ concentration, air temperature, and precipitation) may promote or mitigate the impact of enhanced UV-B radiation on terrestrial ecosystem carbon cycle. This paper introduced the background of UV-B radiation enhancement, reviewed the impacts of enhanced UV-B radiation and its interactions with other climatic factors on terrestrial ecosystem carbon cycle, summarized the existing problems in related researches, and discussed the priorities and directions of future researches.

Research methods of carbon sequestration by soil aggregates: A review.

CHEN Xiao-xia1,2, LIANG Ai-zhen1, ZHANG Xiao-ping1

2012, 23(07):  1999-2006. 

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To increase soil organic carbon content is critical for maintaining soil fertility and agricultural sustainable development and for mitigating increased greenhouse gases and the effects of global climate change. Soil aggregates are the main components of soil, and have significant effects on soil physical and chemical properties. The physical protection of soil organic carbon by soil aggregates is the important mechanism of soil carbon sequestration. This paper reviewed the organic carbon sequestration by soil aggregates, and introduced the classic and current methods in studying the mechanisms of carbon sequestration by soil aggregates. The main problems and further research trends in this study field were also discussed.

Decision support system for watershed management: A review.

CAO Yu， YAN Jing

2012, 23(07):  2007-2014. 

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Watershed management decision support system (DSS) is an intellectual system developed for the optimal allocation of water resources by watershed managers, and the simulation results of the system can directly affect the scientificity and practicability of watershed management. This paper summarized the related researches  from the aspects of water quantity simulation and deployment systems, water quality monitoring and evaluation systems, and integrated watershed management systems. The main features and problems in existing DSS were analyzed, and the model structure and development status of the representative systems such as AQUA-Tool, Elbe-DSS, and HD were introduced. It was suggested that the accuracy and stability of simulated results, the succinctness of working process, and the high degree of user visualization would be the focuses in developing the DSS in the future, and the optimization of programselecting models and 3D visualization tools, the research and development of interbasin integrated management DSS, and the improvement of stakeholder participation would be the development trend for the future watershed management DSS.

Research advances in anaerobic co-digestion of biogas fermentation substrates.

DONG Fei-qing1, LI Xia2, LU Jian-bo2

2012, 23(07):  2015-2025. 

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With global climate change, more and more attention has been paid to the development of bio-energy. Biogas fermentation, as a fairly mature technology of biomatter energy transformation, has received considerable attention and experienced much development. How to improve the efficiency of biogas fermentation and promote its industrialization is a pressing issue. Anaerobic co-digestion is a simple, low-cost, and high-efficiency method for enhancing the efficiency of biogas fermentation, and received increasing attention from related researchers. This paper summarized the characteristics of various fermentation substrates, reviewed the research advances in the co-digestion of animal manure, sewage sludge, and industrial waste, with the focus on the advantages of co-digestion and the factors affecting the rate and efficiency of co-digestion, and prospected the future research of co-digestion and its application, aimed to provide theoretical guidance for the promotion and application of co-digestion techniques.

Thermophiles and their working mechanisms in degrading excess sludge: A review.

YANG Yue, WANG Yun-long, YANG Shang-yuan, LIANG Zhi-wei, LIU Guo-fang, CHEN Ying-xu

2012, 23(07):  2026-2030. 

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Activated sludge process is widely used in treating a wide variety of wastewater, but the by-product is the large amount of excess sludge. To treat the excess sludge  properly could spend 25%-60% of the total cost of wastewater treatment, while improperly treating the sludge could cause serious secondary pollution. Therefore, the reduction of excess sludge is becoming a rising challenge. Using thermophiles to degrade excess sludge is a way easy in operation and inexpensive in maintenance, being a promising method in application. This paper reviewed the recent progress in the researches of sludgedegrading thermophiles, their working mechanisms, and the enzymes from thermophiles, such as thermophilic proteolytic enzymes and thermophilic lipases which play an important role in the degradation of sludge. The factors affecting the degradation of sludge by thermophiles were summarized, and the perspectives for the further research on the application of thermophiles in digesting sludge were discussed.