Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    18 February 2012, Volume 23 Issue 02
    Articles
    Characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in Rainy Area of West China.
    2012, 23(02):  293-300. 
    Asbtract ( 1829 )   PDF (1243KB) ( 784 )  
    To understand the characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in the Rainy Area of West China, a one-year periodic monitoring was conducted in a fixed plot of the plantation from February 2010 to January 2011. In the plantation, the mean annual soil respiration rate was 1.13 μmol·m–2·s–1, and the soil respiration presented a clear seasonal pattern, with the maximum rate in mid-summer and the minimum rate in late winter. The contribution rates of the respiration of litter layer, root-free soil, and root to the total soil respiration of the plantation accounted for 30.9%, 20.8% and 48.3%, respectively, and the respiration of the components had a similar seasonal pattern to the total soil respiration, being related to temperature and litterfall. The annual CO2 efflux from the total soil respiration, litter layer CO2 release, root-free soil CO2 release, and root respiration was 4.27, 1.32, 0.87 and 2.08 Mg C·hm–2·a–1, respectively. The total soil respiration and its components had significant positive linear correlations with litterfall, and significant positive exponential correlations with air temperature and the soil temperature at depth 10 cm. The Q10 values of total soil respiration, litter layer CO2 release, root-free soil CO2 release, and root respiration calculated based on the soil temperature were 2.90, 2.28, 3.09 and 3.19, respectively, suggesting that the temperature sensitivity of litter layer CO2 release was significantly lower than that of the total soil respiration and of its other components.
    Contribution of soil fauna to the mass loss of Betula albosinensis leaf litter at early decomposition stage of subalpine forest litter in western Sichuan.
    2012, 23(02):  301-306. 
    Asbtract ( 1717 )   PDF (638KB) ( 703 )  
    In order to quantify the contribution of soil fauna to the decomposition of birch (Betula albosinensis) leaf litter in subalpine forests in western Sichuan of Southwest China during freeze-thaw season, a field experiment with different mesh sizes (0.02, 0.125, 1 and 3 mm) of litterbags was conducted in a representative birch-fir (Abies faxoniana) forest to investigate the mass loss rate of the birch leaf litter from 26 October, 2010 to 18 April, 2011, and the contributions of micro-, meso- and macro-fauna to the decomposition of the leaf litter. Over the freeze-thaw season, 118%, 132%, 154% and 195% of the mass loss were detected in the litterbags with 002, 0125, 1 and 3 mm mesh sizes, respectively. The total contribution of soil fauna to the litter decomposition accounted for 39.5% of the mass loss, and the taxa and individual relative density of the soil fauna in the litterbags had the similar variation trend with that of the mass loss rate. The contribution rate of soil fauna to the leaf litter mass loss showed the order of micro- < meso- < macro-fauna, with the highest contribution of micro-fauna (7.9%), meso-fauna (11.9%), and macro-fauna (22.7%) at the onset of freezing stage, deeply frozen stage, and thawing stage, respectively. The results demonstrated that soil fauna played an important role in the litter decomposition in subalpine forests of western Sichuan during freeze-thaw season.
    Characteristics of terrestrial ecosystem primary productivity in East Asia based on remote sensing and process-based model.
    2012, 23(02):  307-318. 
    Asbtract ( 1944 )   PDF (4150KB) ( 945 )  
    Based on the bi-linearly interpolated meteorological reanalysis data from National Centers for Environmental Prediction, USA and by using the leaf area index data derived from the GIMMS NDVI to run the process-based Boreal Ecosystems Productivity Simulator (BEPS) model, this paper simulated and analyzed the spatiotemporal characteristics of the terrestrial ecosystem gross primary productivity (GPP) and net primary productivity (NPP) in East Asia in 2000-2005. Before regional simulating and calculating, the observation GPP data of different terrestrial ecosystem  in 15 experimental stations of AsiaFlux network and the inventory measurements of NPP at 1300 sampling sites were applied to validate the BEPS GPP and NPP. The results showed that BEPS could well simulate the changes in  GPP and NPP of different terrestrial ecosystems, with the R2 ranging from 0.86 to 0.99  and the root mean square error (RMSE) from 0.2 to 1.2 g C·m-2·d-1. The simulated values by BEPS could explain 78% of the changes in annual NPP, and the RMSE was 118 g C·m-2·a-1. In 2000-2005, the averaged total GPP and total NPP of the terrestrial ecosystems in East Asia were 21.7 and 10.5 Pg C·a-1, respectively, and the GPP and NPP exhibited similar spatial and temporal variation patterns. During the six years, the total NPP of the terrestrial ecosystems varied from 10.2 to 10.7 Pg C·a-1, with a coefficient of variation being 22%. High NPP (above 1000 g C·m-2·a-1) occurred in the southeast island countries, while low NPP (below 30 g C·m-2·a-1) occurred in the desert area of Northwest China. The spatial patterns of  NPP were mainly attributed to the differences in the climatic variables across East Asia. The NPP per capita also varied greatly among different countries, which was the highest (70217 kg C·a-1) in Mongolia, far higher than that (1921 kg C·a-1) in China, and the lowest (757 kg C·a-1) in India.
    Evaluation of remote sensing extraction methods for vegetation phenology based on flux tower net ecosystem carbon exchange data.
    2012, 23(02):  319-327. 
    Asbtract ( 1922 )   PDF (1169KB) ( 887 )  
    Taking the vegetation phenological metrics derived from the net ecosystem carbon exchange (NEE) data of 72 flux towers in North America as the references, a comprehensive evaluation was conducted on the three typical classes of remote sensing extraction methods (threshold method, moving average method, and function fitting method) for vegetation phenology from the aspects of feasibility and accuracy. The results showed that the local midpoint threshold method had the highest feasibility and accuracy for extracting vegetation phenology, followed by the first derivative method based on fitted Logistic function. The feasibility and accuracy of moving average method were determined by the moving window size. As for the MODIS 16 d composited time-series normalized difference vegetation index (NDVI), the moving average method had preferable performance when the window size was set as 15. The global threshold method performed quite poor in the feasibility and accuracy. Though the values of the phenological metrics extracted by the curvature change rate method based on fitted Logistic function and the corresponding ones derived from NEE data had greater differences, there existed a strong correlation between them, indicating that the vegetation phenological metrics extracted by the curvature change rate method could reflect the real temporal and spatial variations of vegetation phenology.
    Effects of elevated CO2 on forest soil CH4 consumption in Changbai Mountains.
    2012, 23(02):  328-334. 
    Asbtract ( 1438 )   PDF (697KB) ( 742 )  
    Elevated atmospheric CO2 concentration may affect the oxidation rate of methane (CH4) in forest soil. In this study, the effects of a 6-year exposure to elevated CO2 concentration (500 μmol·mol-1) on the soil microbial process of CH4 oxidation under Quercus mongolica seedlings were investigated with open top chamber (OTC), and specific 16S rRNA and pmoA gene fragment primers were adopted to analyze the diversity and abundance of soil methanotrophs. Comparing with that under ambient CO2 and open-air, the soil methane consumption under elevated atmospheric CO2 during growth season was reduced by 4% and 22%, respectively. The specific 16S rRNA PCR-DGGE analysis showed that under elevated CO2, the community structure of methane-oxidizing bacteria (MOB) changed, and the diversity index decreased. Elevated CO2 concentration had no distinct effects on the abundance of TypeⅠ MOB, but decreased the amount of TypeⅡ MOB significantly. The pmoA gene copy number under elevated CO2 concentration decreased by 15% and 46%, respectively, as compared with that under ambient CO2 and open-air. Our results suggested that elevated atmospheric CO2 decreased the abundance and activity of soil methanotrophs, and the main cause could be the increase of soil moisture content.
    Characteristics of carbon storage and sequestration in different age beech (Castanopsis hystrix) plantations in south subtropical area of China.
    2012, 23(02):  335-340. 
    Asbtract ( 1538 )   PDF (524KB) ( 894 )  
    To transform large area pure conifer plantations by planting indigenous and valuable broad-leaved tree species has been advocated as an effective close-to-nature forest management in sub-tropical China. Taking the 10-, 20- and 27-year-old Castanopsis hystrix plantations in Guangxi of South China as test objects and by the methods of plot investigation and biomass measurement, this paper studied the carbon content in different plant organs, litter layers, and soil layers and the carbon storage and its allocation in tree layer, litter layer and soil layer. For the test plantations, the carbon content in different C. hystrix organs ranged from 49.7% to 57.9%, and that in litter layer was 40.8%-50.5%, being higher in fresh litter layer than in semi-decomposed litter layer. The carbon storage in the soil profiles (0-60 cm) increased with plantation age but decreased with soil depth. The total carbon storage in the 10-, 20- and 27-year-old plantations was 18242, 23475 and 26975 t·hm-2, respectively, among which, tree layer, litter layer and soil layer occupied 19.8%, 32.0% and 32.8%, 1.5%, 1.6% and 1.3%, and 78.7%, 664% and 659%, respectively. The annual net carbon sequestration of the 10-, 20- and 27-year-old plantations was 4.70, 5.64 and 5.18 t·hm-2, respectively. It was considered that C. hystrix had a high capability in carbon sequestration, being able to be an ideal tree species for multi-purpose forest management with large and valuable timber production.
    Forest carbon rates at different scales in Northeast China forest area.
    2012, 23(02):  341-346. 
    Asbtract ( 1606 )   PDF (1207KB) ( 799 )  
    To accurately estimate forest carbon storage is of significance in researching terrestrial ecosystem carbon cycle and global change. Based on the survey data from the representative plots in Northeast China forest area (Da Xing’an Mountains, Xiao Xing’an Mountains, Zhangguangcai Mountains and Changbai Mountains) in 2007 and 2008 and the inventory data in the same period, and by using the models for estimating ground tree biomass, shrub biomass, and grass biomass and the Multi N/C 3000 for measuring forest carbon rate in laboratory, this paper calculated the forest biomass and carbon storage in the forest area, and analyzed the variation and stability of the forest carbon
    rates at different scales. There was an obvious difference in the carbon rates among tree organs, being the highest in leaf (04448), followed by in branch (0.4422), bark (0.4398), and trunk (0.4351). In Changbai and Zhangguangcai Mountains, coniferous forest had a higher carbon rate than broad-leaved forest; whereas in Daxing’an and Xiaoxing’an mountains, it was in adverse. In Northeast China forest area, the forest carbon rates were relatively stable, with a total value of 0.44.
    Vegetation succession on retired croplands during their recovery processes in Dan-Han River Watershed of Shaanxi Province, Northwest China.
    2012, 23(02):  347-356. 
    Asbtract ( 1508 )   PDF (716KB) ( 627 )  
    Taking naturally recovering plant communities on the croplands having been retired for different years and distributed on the southern and northern slopes in the Dan-Han River watershed of Shaanxi Province as test objects, an investigation was conducted on their community species composition, diversity characteristics, and community polar ordination. In the study area, the vegetation succession process on the retired croplands followed the stages of annual herb community→perennial herb community→shrub-herb community→arbor-shrub-herb
    community. The formation period for perennial herb community, shrub-herb community, and arbor-shrub-herb community was about 2-5 a, 7-10 a, and more than 30 a, respectively. On the southern and northern slopes, different types of retired croplands had the same vegetation succession stages, and had small discrepancies in species diversity indices. With increasing retired years, the species diversity indices on the southern slope increased after an initial decrease, while those on the northern slope had a fluctuated increase first, and slightly decreased by the end of the 30 a.
    Effects of shading  on two Sphagnum species growth and their interactions. 
    2012, 23(02):  357-362. 
    Asbtract ( 1468 )   PDF (510KB) ( 698 )  
    Taking Sphagnum palustre and S. fallax as test materials, this paper studied their growth and interactions under  shading. In monoculture, shading promoted the height growth of S. palustre markedly, but had no effect on the growth of S. fallax and the biomass and branching of S. palustre. In mixed culture, S. fallax suppressed the increase of biomass and branching of S. palustre, while S. palustre had no effects on S. fallax. With the increase of shading stress, the competition of neighbour on S. fallax intensified. When the stress increased further, neighbor effect on S. fallax tended to be positive. However, the effect of neighbour on S. palustre was always competitive and did not change with the increase of shading stress.
    Effects of desulfurization waste on calcium distribution, Ca2+-ATPase activity, and antioxidant characteristics of rice leaf under alkali stress.
    2012, 23(02):  363-368. 
    Asbtract ( 1467 )   PDF (1278KB) ( 566 )  
    To approach the action mechanisms of desulfurization waste on alleviating alkali stress- induced injury of rice, a pot experiment was conducted to study the variations of leaf total calcium content, calcium distribution, plasma membrane Ca2+-ATPase activity, and reactive oxygen content of rice seedlings under alkali stress after the application of desulfurization waste. In the control, a few calcium particulates scattered in the cell wall and chloroplasts, while applying desulfurization waste or CaSO4 increased the calcium particulates in the plasma membrane, intercellular space, cell wall, and vacuole significantly. With the increasing application rate of desulfurization waste or CaSO4, the leaf total calcium content increased, Ca2+-ATPase activity in plasma membrane and tonoplast presented an increasing trend, plasma membrane relative permeability, MDA content, and O2〖SX(B-*3〗-〖〗·〖SX)〗production rate decreased, and SOD and POD activities increased. The desulfurization waste could relieve the alkali stress to rice in some extent, and the main reactive compound in the waste could be CaSO4.
    Effects of soil moisture before sowing and nitrogen fertilization on winter wheat yield and water use on Weibei Plain of Loess Plateau.
    2012, 23(02):  369-375. 
    Asbtract ( 1598 )   PDF (496KB) ( 632 )  
    A five-year site-specific experiment was carried out on the Weibei Plain of Loess Plateau in  Shaanxi Province of northwestern China to study the effects of soil moisture regime before sowing (SMBS) and nitrogen fertilization on the grain yield and water use of winter wheat. On the basis of applying 100 kg·hm-2 of P2O5, five nitrogen fertilization levels (0, 80, 160, 240, and 320 kg N·hm-2) were installed, and took the precipitation in the five years into consideration. In the study area, there was a linear correlation between the precipitation in summer (from July to September) and the SMBS, with an increment of 0.6 mm SMBS per 1 mm precipitation. For a stable or high wheat yield, the SMBS should be kept around 550 mm, and the precipitation in summer should be around 370-390 mm. In the years with adequate precipitation (>386 mm) in summer, the SMBS in present winter wheat growth season less decreased by the increase of the nitrogen fertilization rate in previous growth season. However, in the years with less precipitation in summer (<350 mm), the SMBS in present winter wheat growth season decreased significantly by 9-17 mm when the nitrogen fertilization rate in previous growth season was increased by each 100 kg N·hm-2. In addition to SMBS, adequate precipitation in key growth stages was another important factor to ensure the wheat yield in dryland area because 1 mm SMBS could produce 106-114 kg·hm-2 of wheat grain, and 1 mm precipitation occurred in the key growth stages could lead to more grain yield as high as 30.6-33.1 kg·hm-2. Variation analysis showed that nitrogen fertilization rate affected the utilization degree of SMBS by winter wheat, while SMBS controlled the allocation and transportation of dry matter from vegetative parts to grain.
    Environmental effects of applying heavy metal-containing municipal sewage sludge on wheat-rice rotation system on different types of soil.
    2012, 23(02):  376-382. 
    Asbtract ( 1399 )   PDF (587KB) ( 578 )  
    A pot experiment with the yellow soil and limestone soil from Guizhou province, and paddy soil from Zhejiang Province was conducted to study the impacts of applying municipal sewage sludge containing different concentrations of heavy metals on the wheat and rice growth and their Zn  and Cd absorption. The risks of the crop heavy metals pollution caused by the application of the same sludge differed with tested soils. On the yellow soil and paddy soil, applying the sludge containing high concentration heavy metals induced higher pollution risks to the crops. Applying the sludge 1.6% in dry mass and containing 1789 mg·kg-1 of Zn and 8.47 mg·kg-1 of Cd to yellow soil made the Zn and Cd concentrations in wheat grains reached 109 and 0.08 mg·kg-1, and after the second time application of the same dosage of this sludge after rice planting, the Zn and Cd concentrations in brown rice reached 52.0 and 0.54 mg·kg-1, respectively. However, applying the sludge to calcareous soil had no pollution risk to the edible parts of wheat and rice. Soil NH4OAc-extractable Zn was the main factor affecting the Zn concentration in wheat grain and brown rice, but soil NH4OAc-extractable Cd had less effect on the Cd concentration in wheat grain and brown rice. Applying the sludge containing high concentration Zn and Cd to the three soils made the concentrations of total Zn and Cd in the soils increased significantly, and after the first time and the second time of the application, the total Zn concentration in the soils all exceeded the 2nd level of the national soil environmental quality standards.
    Effects of organic amendments on the growth and heavy metal uptake of rice on a contaminated soil.
    2012, 23(02):  383-388. 
    Asbtract ( 1392 )   PDF (413KB) ( 684 )  
    A pot experiment was carried out to investigate the effects of three organic amendments (organic carbon material, rapeseed cake, and pig manure) on the growth and heavy metal uptake of rice on a heavy metal mixed contaminated paddy soil. Applying rapeseed cake and pig manure could mitigate the toxic effect of heavy metals on rice plant. The two organic amendments increased the shoot biomass and grain yield significantly, and decreased the heavy metal concentration in brown rice. Under the application of organic carbon material, rice growth was inhibited. As compared with the control, applying rapeseed cake and pig manure increased the grain yield by 1283% and 679%, and decreased the Cd, Cu, and Zn concentrations in brown rice by 476%, 352% and 215%, and 95%, 212% and 93%, respectively. The shoot biomass and its total accumulation of Cd, Cu, and Zn had significant negative correlations with the soil DTPA-extractable heavy metals.
    Effects of tillage mode and deficit irrigation on the yield and water use of transplanted cotton following wheat harvest under sprinkler irrigation.
    2012, 23(02):  389-394. 
    Asbtract ( 1543 )   PDF (557KB) ( 541 )  
    To develop a suitable tillage mode and irrigation schedule of transplanted cotton following wheat harvest under sprinkler irrigation, a field experiment was conducted to study the effects of different tillage modes (conventional tillage and no-tillage) and different irrigation schedules (45 and 22.5 mm of irrigating water quota) on the water consumption, seed yield, water use efficiency, and fiber quality of cotton. Comparing with conventional tillage, no-tillage decreased the soil evaporation among cotton plants by 20.3%. Whether with conventional tillage or with no-tillage, deficit irrigation (22.5 mm of irrigating water quota) did not affect seed yield and fiber quality, while decreased the water consumption and improved the water use efficiency. No-tillage with 22.5 mm of irrigating water quota under sprinkler irrigation not only decreased the soil evaporation effectively, but also achieved water-saving,  high quality and high yield of transplanted cotton following wheat harvest.
    Effects of water storage in deeper soil layers on the root growth, root distribution and economic yield of cotton in arid area with drip irrigation under mulch.
    2012, 23(02):  395-402. 
    Asbtract ( 1618 )   PDF (782KB) ( 586 )  
    Taking cotton cultivar Xinluzao 13 as test material, a soil column culture experiment was conducted to study the effects of water storage in deeper (>60 cm) soil layer on the root growth and its relations with the aboveground growth of the cultivar in arid area with drip irrigation under mulch. Two levels of water storage in 60-120 cm soil layer were installed, i.e., well-watered and no watering, and for each, the moisture content in 0-40 cm soil layer during growth period was controlled at two levels, i.e., 70% and 55% of field capacity. It was observed that the total root mass density of the cultivar and its root length density and root activity in 40-120 cm soil layer had significant positive correlations with the aboveground dry mass. When the moisture content in 0-40 cm soil layer during growth season was controlled at 70% of field capacity, the total root mass density under well-watered and no watering had less difference, but the root length density and root activity in 40-120 cm soil layer under well-watered condition increased, which enhanced the water consumption in deeper soil layer, increased the aboveground dry mass, and finally, led to an increased economic yield and higher water use efficiency. When the moisture content in 0-40 cm soil layer during growth season was controlled at 55% of field capacity and the deeper soil layer was well-watered, the root/shoot ratio and root length density in 40-120 cm soil layer and the root activity in 80-120 cm soil layer were higher, the water consumption in deeper soil layer increased, but it was still failed to adequately compensate for the negative effects of water deficit during growth season on the impaired growth of roots and aboveground parts, leading to a significant decrease in the economic yield, as compared with that at 70% of field capacity. Overall, sufficient water storage in deeper soil layer and a sustained soil moisture level of 65%-75% of field capacity during growth period
     could promote the downward growth of cotton roots, which was essential for achieving water-saving and high-yielding cultivation of cotton with drip irrigation under mulch.
    Effects of nitrogen fertilization rate and planting density on cotton boll biomass and nitrogen accumulation in extremely early maturing cotton region of Northeast China.
    2012, 23(02):  403-410. 
    Asbtract ( 1459 )   PDF (420KB) ( 588 )  
    Taking cotton cultivars Liaomian 19 and NuCoTN 33B as test materials, a field experiment was conducted to study the effects of nitrogen fertilization rate (0, 240 and 480 kg·hm-2) and planting density (75000, 97500 and 120000 plants·hm-2) on the boll biomass and nitrogen accumulation in the extremely early maturing cotton region of Northeast China. With the growth and development of cotton, the biomass and nitrogen accumulation of cotton boll, cotton seed, and cotton fiber varied in ‘S’ shape. Both nitrogen fertilization rate and planting density had significant effects on the dynamic characteristics of boll biomass and nitrogen accumulation, and on the fiber yield and quality. In treatment 240 kg·hm-2 and 97500 plants·hm-2, the biomass of single boll, cotton seed and cotton fiber was the maximum, the starting time and ending time of the rapid accumulation period of the biomass and nitrogen were earlier but the duration of the accumulation was shorter, the rapid accumulation speed of the biomass was the maximum, and the distribution indices of the biomass and nitrogen were the lowest in boll shell but the highest in cotton seed and cotton fiber.
    Effects of applying selenium on selenium allocation, grain yield, and grain quality of two maize cultivars.
    2012, 23(02):  411-418. 
    Asbtract ( 1485 )   PDF (485KB) ( 671 )  
    A pot experiment with conventional maize cultivar ZD958 and glutinous maize cultivar JN218 was conducted to study the effects of applying different concentrations (0, 10, 25 and 50 mg·kg-1) of selenium (Se) on the Se allocation in plant organs, grain yield, and its quality. At low concentrations (≤10 mg·kg-1), Se stimulated maize growth, and increased biomass accumulation and grain yield significantly. At high concentrations (≥25 mg·kg-1), Se inhibited maize growth, and decreased dry mass accumulation, grain yield, and its quality. The Se concentration in plant organs was in the order of root > leaf > stalk > sheath. The Se concentrations in plant organs had a positive correlation with the Se concentration in soil. Comparing with ZD958, JN218 could accumulate more Se in natural low-Se environment, but enrich lesser Se in the environment with 10 mg·kg-1 of Se. Taking the Se accumulation amount in grain and aboveground vegetative organs as the standard for evaluation, JN218 was more available planted on natural low-Se (0.25 mg·kg-1) soil or high-Se (25 mg·kg-1) soil, while ZD958 was appropriate planted on Se-rich (10 mg·kg-1) soil or Se-polluted (50 mg·kg-1) soil.
    Effects of organic fertilizer application rate on leaf photosynthetic characteristics and grain yield of dryland maize.
    2012, 23(02):  419-425. 
    Asbtract ( 1443 )   PDF (661KB) ( 806 )  
    A 4-year field experiment was conducted at the Heyang Research Station in Weibei dryland to study the effects of organic fertilizer application rate on the leaf photosynthetic characteristics and grain yield of dryland maize. Comparing with applying chemical fertilizer, applying organic fertilizer increased the leaf photosynthetic rate and stomatal conductance, but decreased the leaf intercellular CO2 concentration at each growth stage of maize significantly. With the increasing application rate of organic fertilizer, the leaf photosynthetic rate and stomatal conductance at each growth stage of maize had a gradual increase, while the leaf intercellular CO2 concentration had a gradual decrease. The leaf photosynthesis of maize at each growth stage was controlled by non-stomatal factors, and the application of organic fertilizer reduced the non-stomatal limitation on the photosynthesis performance significantly. The 4-year application of organic fertilizer improved soil nutrient status, and soil nutrients were no longer the main factors limiting the leaf photosynthetic rate and grain yield of maize.
    Climatic suitability of single cropping rice planting region in China.
    2012, 23(02):  426-432. 
    Asbtract ( 1516 )   PDF (982KB) ( 753 )  
    To clarify the leading climate factors affecting the distribution of single cropping rice planting region in China at national and annual temporal scales and to reveal the potential distribution and climatic suitability divisions of this planting region in China could not only provide scientific basis for optimizing the allocation of single cropping rice production, modifying planting pattern, and introducing fine varieties, but also ensure the food security of China. In this paper, the potential climate factors affecting the single cropping rice distribution in China at regional and annual scales were selected from related literatures, and the single cropping rice geographic information from the national agro-meteorological observation stations of China Meteorological Administration (CMA), together with the maximum entropy model (MaxEnt) and spatial analyst function of ArcGIS software, were adopted to clarify the leading climate factors affecting the potential distribution of single cropping rice planting region in China, and to construct a model about the relationships between the potential distribution of the planting region and the climate. The results showed that annual precipitation, moisture index, and days of not less than 18 ℃ stably  were the leading climate factors affecting the potential distribution of single cropping rice planting region in China, with their cumulative contribution rate reached 94.5% of all candidate climate factors. The model constructed in this paper could well simulate the potential distribution of single cropping rice planting region in China. According to the appearance frequency, the low, medium and high climatic suitability divisions of single cropping rice planting region in China were clarified, and the climate characteristics of the planting region in each climatic suitability division were analyzed.
    Variations of microbial biomass and hydrolase activities in purple soil under different cropping modes as affected by ginger planting.
    2012, 23(02):  433-438. 
    Asbtract ( 1516 )   PDF (680KB) ( 538 )  
    This paper studied the variations of soil microbial biomass C, N, and P contents and soil hydrolase activities under different cropping modes, i.e., corn + sweet potato intercropping (CS), soybean mono-cropping (SM), continuous cropping of ginger (CG), and rice-milk vetch rotation (RM), after ginger planting in the purple soil area at the lower reaches of Minjiang River. Ginger planting decreased the soil microbial biomass C, N and P contents significantly. The decrement of the soil microbial biomass C and N contents after ginger planting was lesser under CS and RM than under SM and CG, but the soil microbial biomass P content was in adverse. Ginger planting also decreased the soil acid phosphatase activity significantly, and the decrement was the greatest under CS but the least under RM. The soil invertase activity decreased significantly under CG, and the soil urease activity had a significant decrease under SM, CG and RM. After ginger planting, the soil urease and intervase activities under CS were higher, as compared with those under the other cropping modes.
    Effects of tillage mode on black soil’s penetration resistance and bulk density.
    2012, 23(02):  439-444. 
    Asbtract ( 1702 )   PDF (734KB) ( 701 )  
    Taking an eight-year field experiment site in Dehui County of Jilin Province, Northeast China as test object, this paper studied the effects of different tillage modes (no tillage and ploughing in autumn) on the penetration resistance and bulk density of black soil. No tillage increased the soil penetration resistance, especially at the soil depth of 2.5-17.5 cm. In the continuous cropping of maize and the rotation of maize-soybean, the maximum soil penetration resistance at planting zone under no tillage and ploughing in autumn was 2816 and 1931 kPa, and 2660 and 2051 kPa, respectively, which had no restriction on the crop growth. The curve of soil penetration resistance under 
    ploughing in autumn 
     changed with ridge shape, while that under no tillage changed less. Comparing with ploughing in autumn, no tillage increased the bulk density of 5-20 cm soil layer significantly. Under no tillage, the bulk density of 5-30 cm soil layer changed little, but under ploughing in autumn, soil bulk density increased gradually with increasing soil depth. There was no significant correlation between soil bulk density and soil penetration resistance.
    Relationships between soil nutrient contents and soil enzyme activities in Pinus massoniana stands with different ages in Three Gorges Reservoir Area. 
    2012, 23(02):  445-451. 
    Asbtract ( 1756 )   PDF (744KB) ( 924 )  
    Based on the measurements of soil nutrient contents and enzyme activities and the canonical correspondence analysis (CCA), this paper studied the relationships between soil nutrient contents and soil enzyme activities in different age Pinus massoniana stands in Three Gorges Reservoir Area. Among the test stands, mature stand had the highest contents of organic matter, total nitrogen, ammonium nitrogen, and available phosphorus in 0-20 cm soil layer, followed by middle-aged stand, and nearly-mature stand. With the increase of the stand age, soil invertase activity increased after an initial decrease, cellulase and polyphenoloxidase activities decreased gradually, while urease and peroxidase activities decreased after an initial increase. CCA analysis showed that the effects of the main soil parameters on the soil enzyme activities in the stands ranked in the sequence of total nitrogen > organic matter > pH > bulk density > ammonium nitrogen > available phosphorus. Soil invertase activity had significant positive correlations with soil organic matter, total nitrogen, and total phosphorus, while soil peroxidase activity significantly negatively correlated with soil organic matter, total nitrogen, total phosphorus, and bulk density.  The soil was rich in main nutrients, invertase activity was relatively high, while peroxidase activity was relatively low. The activities of soil invertase, cellulase  and peroxidase could be used as the good biological indicators in evaluating soil quality and fertility.
    Prediction of regional soil quality based on mutual information theory integrated with decision tree algorithm.
    2012, 23(02):  452-458. 
    Asbtract ( 1493 )   PDF (502KB) ( 653 )  
    In this paper, some main factors such as soil type, land use pattern, lithology type, topography, road, and industry type that affect soil quality were used to precisely obtain the spatial distribution characteristics of regional soil quality, mutual information theory was adopted to select the main environmental factors, and decision tree algorithm See5.0 was applied to predict the grade of regional soil quality. The main factors affecting regional soil quality were soil type, land use, lithology type, distance to town, distance to water area, altitude, distance to road, and distance to industrial land. The prediction accuracy of the decision tree model with the variables selected by mutual information was obviously higher than that of the model with all variables, and, for the former model, whether of decision tree or of decision rule, its prediction accuracy was all higher than 80%. Based on the continuous and categorical data, the method of mutual information theory integrated with decision tree could not only reduce the number of input parameters for decision tree algorithm, but also predict and assess regional soil quality effectively.
    Evaluation of land resources carrying capacity of development zone based on planning environment impact assessment.
    2012, 23(02):  459-467. 
    Asbtract ( 1741 )   PDF (1658KB) ( 628 )  
    Assessment of land resources carrying capacity is the key point of planning environment impact assessment and the main foundation to determine whether the planning could be implemented or not. With the help of the space analysis function of Geographic Information System, and selecting altitude, slope, land use type, distance from resident land, distance from main traffic roads, and distance from environmentally sensitive area as the sensitive factors, a comprehensive assessment on the ecological sensitivity and its spatial distribution in Zhangzhou Merchants Economic and Technological Development Zone, Fujian Province of East China was conducted, and the assessment results were combined with the planning land layout diagram for the ecological suitability analysis. In the Development Zone, 84.0% of resident land, 93.1% of industrial land, 86.0% of traffic land, and 760% of other constructive lands in planning were located in insensitive and gently sensitive areas, and thus, the implement of the land use planning generally had little impact on the ecological environment, and the land resources in the planning area was able to meet the land use demand. The assessment of the population carrying capacity with ecological land as the limiting factor indicated that in considering the highly sensitive area and 60% of the moderately sensitive area as ecological land, the population within the Zone in the planning could reach 240000, and the available land area per capita could be 134.0 m2. Such a planned population scale is appropriate, according to the related standards of constructive land.
    Eco-hydrological characteristics and soil and water conservation effect of citrus plantation on slope red soil of Jiangxi Province, China.
    2012, 23(02):  468-474. 
    Asbtract ( 1486 )   PDF (725KB) ( 722 )  
    A 9-year observation was conducted at the experimental plots in the Citrus reticulata plantation in Jiangxi Provincial Eco-Technology Park to study the eco-hydrological characteristics and soil conservation benefits of the plantation on slope red soil. Seven treatments were designed and monitored over nine years. The average flow and the rate of sediment for the seven treatments were reduced by 78.5% and 77.2%, respectively. The reduction rates were the highest in treatments band coverage of Paspalum natatu, whole coverage of P. natatu, and level terrace with grass on ridge, with the values of 94.8%, 94.3% and 92.5%, respectively, followed by in treatment intercropping Glycine max (66.0%) and Raphanus sativus (77.5%), with horizontal planting being better than vertical planting, and the lowest in treatment without understory vegetation (331%). The observations on the precipitation redistribution of 43 rainfall events with a mean precipitation of 20.07 mm in 2009-2010 showed that the throughfall, stemflow, and canopy interception were 9.15, 4.72 and 6.20 mm, accounting for 44.7%, 25.7% and 29.6% of the precipitation, respectively. The throughfall and stemflow tended to increase with increasing precipitation. There was a significant liner negative correlation between the canopy interception rate and the precipitation when the rainfall was less than 10 mm, but no significant correlation when the rainfall was greater than 10 mm. The water holding rate of C. reticulata litters was logarithmically correlated with water soaking time, and the maximum water holding rate was 326%. It was considered that rational allocation of understory vegetation played an important role in the soil and water conservation of citrus orchard on slope red soil.
    Optimization of conservation network system for inter-basin wetland ecosystem in Huang-Huai-Hai Region.
    2012, 23(02):  475-482. 
    Asbtract ( 1394 )   PDF (1213KB) ( 578 )  
    By using systematic conservation planning (SCP) method, and taking catchment as planning unit, an optimization of conservation network system for the inter-basin wetland ecosystem in Huang-Huai-Hai Region was conducted, with a comprehensive consideration of 3-dimensional (lateral, longitudinal and vertical) connectivity and Inter-basin Water Transfer Project and by the methods of irreplaceability analysis and gap identification. The efficacy of the optimized conservation network system was evaluated, as compared with the existing conservation network system. According to the principles of irreplaceability and connectivity, the wetland conservation gaps could be divided into two types, i.e., be conserved in priority and in general. After the optimization, the conservation status of the inter-basin wetland ecosystem in Huang-Huai-Hai Region had an overall improvement. The conserved percentage of the wetland types was from about 20% up to 46.8%, and, for each wetland type, its conserved level increased to some extent, almost above 40%. Both in the near future and in the long term, more attention should be paid to the conservation of lake wetland. In addition, the integration of ecosystem service function and biodiversity and the combination of protection with restoration would be the main task for the wetland ecosystem conservation planning in the future.
    Application of carrying capacity assessment in spatial allocation of regional population: A case of  Changzhou City of East China.
    2012, 23(02):  483-490. 
    Asbtract ( 1321 )   PDF (2121KB) ( 722 )  
    Based on the spatial differences in urban ecosystem carrying capacity, and by using geographic information system (GIS) spatial analysis technology and system dynamics (SD) model, this paper ascertained the moderate population size in urban area and its subareas, and presented an alternative method for quantitatively allocate the population. This method was applied in Changzhou, a city with more than three million populations in East China. A SD model consisted of population, economy, land and environment modules for the city was established and scenario analysis was made. The results showed that under the requirements of satisfying both economic development and environmental protection, the total population in the city in 2050 would reach nearly 4 million, and according to the differences in the urban ecosystem carrying capacity, a spatial allocation pattern of 2.4 million populations in main city and 150000-400000 populations in each of 5 new towns was proposed. This study could provide scientific support for the spatial allocation of population and economy in country land development and management.
    Breeding habitat characteristics of red-crowned crane at Zhalong of Northeast China: A multi-scale approach based on TM and ASAR image data.
    2012, 23(02):  491-498. 
    Asbtract ( 1524 )   PDF (1486KB) ( 1100 )  
    Based on the Landsat TM and Envisat ASAR HH/HV imagery data and by using the GPS data of red-crowned crane nesting sites (n=28) at Zhalong National Nature Reserve of Northeast China, the models of the breeding habitat selection of red-crowned crane at the Reserve were established by binary Logistic regression to identify the key variables for the habitat selection at eight spatial scales (30-240 m). The relative performance of the two models based on the Landsat TM and Envisat ASAR HH/HV databases was compared, and the prediction capacity of the models across the eight scales was approached. The overall precisions of the two models were satisfactory (≥ 69.0%). At scale 30 m, only variable TCA_2 entered with negative value into the model based on Landsat TM database, which indicated that the crane at this scale avoided selecting higher density reed marshes. At scales 60-120 m, the variable PCA_2 entered with positive value into the two models, indicating that the crane at these scales had higher demand of high density reed marshes to improve its concealment. At scale 90 m, the variable HV backward scatting coefficient also entered into the combined model, which indicated that water condition was the important factor for the habitat selection of the crane at this scale. At scales >120 m, the texture information of the two satellite sensors started to be involved into the two models, indicating that at larger scales, the crane had decreasing demand on the vegetation features for its breeding habitat selection but increasing sensitivity to the anthropogenic disturbance factors. The introduction of ASAR variables into the models increased the prediction accuracy of the models markedly at all scales.
    Emergy of agro-ecosystem in Hunan Province: Evolution and trend.
    2012, 23(02):  499-505. 
    Asbtract ( 1453 )   PDF (449KB) ( 725 )  
    By using emergy analysis method, a trend analysis was made on the total emergy, its input-output structure, and emergy indices of the agro-ecosystem in Hunan Province of South-central China from 1999 to 2008. In the study period, the available total emergy input of the ecosystem was basically maintained at a stable level, but the input structure  changed with the input of non-renewable industrial auxiliary emergy increased from 4.00E+22 sej in 1999 to 5.53E+22 sej in 2008, while that of renewable organic emergy decreased from 1.32E+23 sej to 1.20E+23 sej. Both the total emergy output and the output efficiency of the ecosystem had a great increase, with the total output reached 1.69E+23 sej in 2008, which was 23.8% higher than that in 1999, and the net output ratio increased from 0.79 to 0.96. Owing to the ever-increasing trend of the environmental loading ratio which was from 1.12 to 1.79, the sustainable development index of the ecosystem presented a decreasing trend, from 0.71 to 0.54, indicating that the agriculture in Hunan Province was overall belonged to the type of ecosystem driven by high consumption, and had relatively apparent extensive development characteristics.
    Effects of high temperature on the mortality and fecundity of two co-existing cotton aphid species Aphis gossypii Glover and Acyrthosiphon gossypii Mordvilko. 
    2012, 23(02):  506-510. 
    Asbtract ( 1436 )   PDF (577KB) ( 617 )  
    Aphis gossypii and Acyrthosiphon gossypii are the coexisting species on cotton plant, with their abundance differed within and among years. To explore whether the abundance difference was related to the different responses of the two aphid species to high temperature, a laboratory experiment was conducted to assess the mortality and reproduction of the two aphid species at high temperatures 32, 34, 36 and 38 ℃. With the increasing temperature and prolonged exposure period, the cumulative mortality of the two aphid species increased, and Acyrthosiphon gossypii had a higher cumulative mortality than Aphis gossypii. The daily mortality of the aphids could be well simulated by complementary log-log (CLL) model. The median lethal temperature of the two aphid species estimated by CLL model decreased with prolonged exposure period. Under the same exposure period, the median lethal temperature of Aphis gossypii was higher than that of Acyrthosiphon gossypii. Within the range of 32-38 ℃, the reproduction rate of the two aphid species decreased with increasing temperature, but Aphis gossypii had a significantly higher reproduction rate than Acyrthosiphon gossypii, indicating that at the temperature higher than 32 ℃, Aphis gossypi had higher tolerance against high temperature than Acyrthosiphon gossypii, and consequently, had more competitive advantage under global warming.
    Diversity of antagonistic bacteria isolated from rhizosphere of several cash crops.
    2012, 23(02):  511-518. 
    Asbtract ( 1460 )   PDF (1316KB) ( 684 )  
    By adopting antimicrobial spectrum test, BOXAIR-PCR, physiological and biochemical, and 16S rDNA sequencing analysis, this paper analyzed the diversity of 55 antagonistic bacterial strains isolated from the  rhizosphere  of 10 cash crops. There was a high diversity of the antagonism of the strains. Based on BOXAIR-PCR, all the strains were clustered into 7 groups at the similarity level of 721%, and divided into 25 groups at the similarity level of 850%. All the strains belonged to Bacillus, Paenibacillus, Brevibacillus, Pseudomonas and Alcaligenes, respectively. The antagonistic bacteria isolated from the rhizosphere had high genetic diversity and high diversity in antagonistic activity.
    Stress resistance and genetic diversity of endophytic bacteria isolated from Caragana spp. root nodules.
    2012, 23(02):  519-524. 
    Asbtract ( 1473 )   PDF (1006KB) ( 526 )  
    By adopting PCR-RFLP and 16S rDNA sequencing, this paper analyzed the genetic diversity and phylogeny of 40 endophytic bacterial strains isolated from Caragana spp. root nodules, and determined the salt resistance, acid- and alkali resistance, and growth temperature range of the strains. A total of 9 genotypes were obtained from the 40 strains by RFLP. The 16S rDNA sequencing, morphological observation, and biochemical test of representative strains showed that the strains belonged to Bacillus, Inquilinus, Shinella and Acinetobacter, respectively, and had rich genetic diversity. 57.5% of the strains could tolerate 4% NaCl stress, 75% of the strains could grow in YMA medium with an initial pH 11.0, and 85% of the strains could survive after heat shock treatment at 60 ℃, suggesting that the endophytic bacteria of Caragana spp. had strong resistance capacity. Among the strains, LWEN 07 and LWEN 15 were most resistant.
    Residue of chlorpyrifos and its degradation dynamics in Chinese chive (Allium tuberosum) plant and soil.
    2012, 23(02):  525-530. 
    Asbtract ( 1431 )   PDF (481KB) ( 557 )  
    This paper studied the residue of chlorpyrifos and its degradation dynamics in Chinese chive (Allium tuberosum) plant and soil after irrigating different concentrations of this pesticide into A. tuberosum root zone under plastic greenhouse and open-field cultivated conditions. The chlorpyrifos  in A. tuberosum plant had a faster degradation rate than that in soil, with an average half-life of the pesticide being 3.41 and 7.40 days in the plant and soil, respectively. Under the conditions of plastic greenhouse and open-field cultivation, the degradation rate of chlorpyrifos in A. tuberosum plant had less difference, with the average half-life of chlorpyrifos being 3.37  and 3.44 days, respectively. 21 days after irrigating into root zone, the chlorpyrifos (0021-0102 mg·kg-1) in A. tuberosum plant did not exceed the maximum residue limit (≤0.01 mg·kg-1, GB 2763—2005). A few chlorpyrifos residue was found in the new growth parts of A. tuberosum, but the residue concentration was obviously lower than that in the first harvested plant after irrigating this pesticide. The chlorpyrifos residue in soil had significant effects on the residue of the pesticide in A. tuberosum plant.
    Biological activity of capsaicin and its effects on development and fecundity in Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae).
    2012, 23(02):  531-535. 
    Asbtract ( 1638 )   PDF (386KB) ( 793 )  
    Biological activity of capsaicin and its effects on development and fecundity in Bemisia tabaci were tested in the laboratory. The results showed that capsaicin induced direct mortality in different developmental stages of B. tabaci, and the mortality of whiteflies were significantly dosage-dependent. The toxicity of capsaicin to different developmental stages of B. tabaci by either leaf-dip or egg/larval-dip bioassays (the LC50 for adult, egg and nymph were 3525.79, 1603.29 and 152627 mg·L-1, respectively) was higher than that by systemic bioassay (the LC50 for adult, egg and nymph were 5360.04, 2359.19 and 5897.43 mg·L-1, respectively),and toxicity of capsaicin to eggs was higher than to adults in both bioassay methods. 2000 and 4000 mg·L-1 concentrations of capsaicin had strong antifeedant effect on B. tabaci, as exemplified by reduced honeydew excretion of adults feeding on leaves treated with capsaicin compared with untreated leaf discs. Capsaicin also had strong oviposition deterrence against B. tabaci, with 94.2% of selective oviposition deterrence rate and 83.0% of nonselective oviposition deterrence rate when exposed to 4000 mg·L-1 concentration for 24 h. We did not find effect on development time of B. tabaci eggs and nymphs, and on molting rate of adults when exposed to capsaicin at 500, 1000 and 2000 mg·L-1 concentrations, however, exposure to 4000 mg·L-1 concentration of capsaicin significantly affected development time of B. tabaci nymphs and molting rate of adults. Exposure to capsaicin also significantly reduced fecundity of B. tabaci adults, and this reduction was significantly dosage-dependent.
    Dietary composition and food competition of six main fish species in rocky reef habitat off Gouqi Island.
    2012, 23(02):  536-544. 
    Asbtract ( 1592 )   PDF (677KB) ( 689 )  
    Based on the monthly investigation data of fish resources in the rocky reef habitat off Gouqi Island
     from March 2009 to February 2010, this paper studied the dietary composition of three native fish species (Sebasticus marmoratus, Hexagrammos otakii and Hexagrammos agrammus) and three non-native fish species (Lateolabrax japonica, Nibea albiflora and Larimichthys polyactis). The analysis of gut content indicated that the main prey items of these six dominant fish species were Caprellidae, Gammaridea, juvenile S. marmoratus, Engraulis japonicas and Acetes chinensis and the dietary composition of each of the 6 fish species had obvious seasonal variation. There was an intense food competition between native species H. otakii and H. agrammus in autumn, between non-native species N. albiflora and L. polyactis in summer, between non-native species N. albiflora and native species S. marmoratus in autumn, and between non-native species N. albiflora and native species H. otakii in winter. It was suggested the non-native species N. albiflora was the key species in the food competition among the six dominant fish species in this rocky reef habitat, and thus the feeding behaviors of these six fish species could have definite effects on the resource capacity of juvenile S. marmoratus.
    Community structure of fish in Zhoushan Fishing Ground and its adjacent waters in spring and summer.
    2012, 23(02):  545-551. 
    Asbtract ( 1627 )   PDF (738KB) ( 887 )  
    Based on the investigation data of the fishery resources and environment in Zhoushan Fishing Ground and its adjacent waters in August 2006 and April 2007, and by using multi-dimensional scaling (MDS) and canonical correspondence analysis (CCA), this paper studied the species composition and the characteristics of fish community in the area. In spring, a total of 62 fish species were captured, belonging to 56 genera, 36 families and 11 orders. The dominant species were Amblychaeturichthys hexanema and Larimichthys polyactis, and their abundance occupied 829% of the total. In summer, 58 fish species were captured, belonging to 51 genera, 38 families and 11 orders. Amblychaeturichthys hexanema, Champsodon snyderi, Dysomma anguillaaris and Acropoma japonicum were the dominant species, with the abundance accounted for 60.8% of the total. In the two seasons, twenty stations were separated into three groups. Among the fishes captured, 26 and 30 fish species had an occurrence rate larger than 5.0% in spring and summer, respectively, and formed two and three assemblages correspondingly.
    Spatial distribution of wintering Engraulis japonicus and its relationship with the inter-annual variations of water temperature in central and southern Yellow Sea.
    2012, 23(02):  552-558. 
    Asbtract ( 1654 )   PDF (1027KB) ( 630 )  
    This paper studied the inter-annual variations in the spatial distribution of wintering anchovy (Engraulis japonicus) in central and southern Yellow Sea, based on the 1986-2010 bottom trawl survey data and related sea surface temperature (SST) data obtained by remote sensing, and approached the relationships between the inter-annual variations in the spatial distribution of the wintering anchovy and the SST, by using GIS technique, spatial analysis and correlation analysis. In 1986-2010, the wintering anchovy in the study area had apparent inter-annual variations in spatial distribution, with its abundance dropped to the lowest level and its distribution moved shoreward in 2004, and the abundance rebounded and centralized in the eastern waters in 2010. The centralized distribution regions of the anchovy’s capture locations and stock density in longitudinal and latitudinal directions also had apparent inter-annual variations. There was a significant correlation between the latitude of the anchovy’s stock density center and the mean latitude of the representative isotherms, suggesting that the variations in water temperature had effects on the latitudinal distribution of the wintering anchovy, and whether the anchovy distributed shoreward or not was determined by the inter-annual variations of Yellow Sea Warm Current. Among the factors affecting the anchovy distribution, fishing pressure was the main factor affecting the changes in anchovy abundance, and water temperature mainly determined the changes in anchovy spatial distribution.
    Characteristics of Pomacea canaliculata reproduction under natural conditions.
    2012, 23(02):  559-565. 
    Asbtract ( 1595 )   PDF (1304KB) ( 564 )  
    A three-year breeding experiment was conducted in a paddy field in Zixing City of Hunan Province, South-central China to study the characteristics of golden apple snail (Pomacea canaliculata) reproduction under natural conditions. Under the natural conditions in southern Hunan Province, the snails could approximately reproduce three generations per year. The average sexual maturity periods of the first, the second, and the third generation of the female snails were 59.3, 45.4 and 213.0 days, respectively, and those of the male snails were 4.3
     days earlier than the females’. The natural sex ratio of the females to the males was 1.54:1. The average copulation duration was 19.2
     hours, but spawning did not always occur after each time of copulation. The number of the egg masses produced by the females per month was significantly positively correlated with the mean monthly air temperature (r=0.756), while the average incubation duration of the egg masses was significantly negatively correlated with the daily air temperature (y=-0.726x+23.064, r=-0980). The average incubation time of the egg masses was 20.7 days, average incubation rate was 44.1%, and the average life expectancy of the female and male snails was 2.40 and 1.98 years, respectively. A female snail in its lifetime could averagely spawn 13764  eggs and reproduce 6070 young snails.
    Underlying mechanisms and related techniques of stand establishment of cotton on coastal saline-alkali soil.
    2012, 23(02):  566-572. 
    Asbtract ( 1397 )   PDF (2140KB) ( 559 )  
    Stand establishment is the most difficult step for cotton planting on coastal saline-alkali soil. To establish and improve the techniques for stand establishment is the key in the production of high-yielding cotton on saline-alkali soil. Based on the previous studies and our own research progress in this field, this paper reviewed the effects and the underlying mechanisms of making unequal salt distribution in root zone, increasing soil moisture and temperature, establishing under-mulching greenhouse, and introducing seed coating agent in promoting stand establishment of cotton on saline-alkali soil. It was suggested that under the conditions of the average salt content in topsoil being not able to reduce, improving at least partial root zone environment through the induction of unequal salt distribution in the root zone and increasing soil moisture and temperature could significantly reduce salt injury and improve stand establishment. Flat seeding under plastic mulching on low-salinity soil, furrow seeding with mulching on moderate- or high-salinity soil, early mulching before sowing on rain-fed saline soil, and late sowing of short-season cotton in heat-limited area were the efficient techniques for improving the stand establishment of cotton on coastal saline-alkali soil. This review could provide full guarantee for the cotton stand establishment on coastal saline-alkali soil.
    Roles of glucosinolates in the interrelationships between Brassicaceae plants and insects: A review.
    2012, 23(02):  573-580. 
    Asbtract ( 1388 )   PDF (525KB) ( 584 )  
    Glucosinolates (GS) are the important secondary metabolites of Brassicaceae plants, playing an important role in regulating the interrelationships between Brassicaceae plants and insects. GS can protect Brassicaceae plants against euryphagous herbivorous pests because of the toxicity of GS and their breakdown products. However, oligophagous pests which have evolved manifold metabolic pathways to cope with the defensive compounds depended fully on GS and their volatile breakdown products for host-plant recognition and orientation. The GS ingested by herbivores are also toxic to carnivores, and can directly deter predators. On the other hand, predators and parasitoids are attracted by the volatile breakdown products of GS from the Brassicaceae plants damaged by herbivores. Based on the recent findings, this paper reviewed the defensive function of GS against herbivores, host selection of oligophagous pests, GS metabolic pathways of herbivores, induction of GS by herbivores, and effects of GS on the third tropic level. Future directions and techniques in this research field were also suggested.