Table of Content

20 September 2009, Volume 20 Issue 09

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Articles

Classification, species diversity, and species distribution gradient of permafrost wetland plant communities in Great Xing’an Mountains valleys of Northeast China.

2009, 20(09):  2049-2056. 

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By using two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA), this paper analyzed the environmental gradients of the species diversity and distribution of permafrost wetland plant communities in 12 valleys at different latitudes of the Great Xing’an Mountains. The plant communities in the 12 valleys could be classified into four plant associations, based on the latitudes. The classification results of TWINSPAN reflected well the relationships between the distribution of the plant associations and the latitudes, and these relationships were better validated by DCA ordination. The species diversity increased with decreasing latitude and increasing mean annual temperature, mean annual precipitation, mean temperature in January, and aridity. The dominant and co-dominant species in shrub and herb layers were mostly helophytes and hygrophytes. With decreasing latitude, the helophytes and hygrophytes decreased or disappeared, while mesophytes increased.

Life form spectra, leaf character, and hierarchical-synusia structure of vascular plants in Thuja sutchuenensis community.

2009, 20(09):  2057-2062. 

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Based on the investigation of the plants in Thuja sutchuenensis community, t
he life form spectra, leaf character, and hierarchical-synusia structure
 in the community were analyzed. The life form spectra of the plants in the comm
unity were 732% of phanemphyte, 18% of hemicryptophyte, 6% of geophyte, 2% of
chamaephyte, and 08% of annual plants. The leaf quality was mainly of papery a
nd conaceous, which occupied 488% and 364%, respectively. The dominant leaf
size was microphy (608%), dominant leaf margin was un-entire (568%), and do
minant leaf form was simple (86%). The T. sutchuenensis community had three
sub-layers, i.e. tree layer, shrub layer, and herb layer, with lesser interlayer p
lants. Each layer was respectively composed by phanemphyte evergreen coniferophy
te, broadleaf and deciduous broad-leaf plants, nanophanerophyte evergreen and d
eciduous broad-leaf plants, as well as hemicryptophyte, geophyte, and annual pl
ants.

Effects of nitrogen fertilization on seasonal dynamics of soil microbial biomass carbon and nitrogen in Larix gmelinii and Fraxinus mandshurica plantations.

2009, 20(09):  2063-2071. 

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This paper studied the seasonal dynamics of soil microbial biomass C (Cmic) and N (Nmic), and of bacteria (cfub), fungi (cfuf), and actinomyces (cfua) in Larix gmelinii and Fraxinus mandshurica plantations in 2007〖KG-*2〗-〖KG-*7〗2008 under N fertilization. The two-year averaged soil Cmic and Nmic in L. gmelinii plantation were 138% and 183% lower than those in F. mandshurica plantation, respectively, but the soil Cmic and Nmic in the two plantations had similar seasonal patterns, being the lowest in May and the highest in September. The Cmic and Nmic, and the cfub, cfuf, and cfua were all greater in topsoil (0〖KG-*2〗-〖KG-*7〗10 cm) than in subsoil (10〖KG-*2〗-〖KG-*7〗20 cm), but the seasonal patterns of cfub, cfuf, and cfua were different from those of Cmic and Nmic. N fertilization decreased the Cmic and Nmic, and the
cfub, cfuf, and cfua significantly, with the decrements of Cmic and Nmic being 24% and 63% in L. gmelinii plantation, and 51% and 68% in F. mandshurica, respectively, which suggested that N fertilization limited soil microbial biomass and altered soil microbial communities in the two plantations.

Soil microbial biomass in Larix gmelinii forests along a latitudinal gradient during spring soil thawing.

2009, 20(09):  2072-2078. 

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The 8-year-old Larix gmelinii forests were transplanted from four sites (Tahe, Songling, Sunwu, and Dailing) comprising a latitudinal gradient across the distribution range of L. gmelinii in Northeastern China, and the soil microbial biomass carbon (Cmic) and nitrogen (Nmic) in spring soil thawing period were measured after 3-year transplanting. Under the similar soil substrates and the same climate conditions, the mean values of soil Cmic and Nmic in the L. gmelinii forests transplanted from the four sites differed significantly, being decreased with increasing latitude and soil depth. The Cmic for Tahe, Songling, Sunwu, and Dailing averaged 55463, 82641, 87481, and 124618 mg·kg-1, and the Nmic averaged 7063, 9678, 7976, and 11966 mg·kg-1, respectively. The Cmic and Nmic peaked before soil thawing, declined rapidly at the early stage of soil  thawing, and had less change and maintained at a lower level during the period of soil freezing-thawing. By the end of soil thawing, the Cmic for lower latitudinal soils (i.e., Dailing and Sunwu) recovered faster. Soil temperature and moisture content during spring soil thawing affected the temporal patterns of Cmic and Nmic significantly, but the affecting degree depended on the stages of soil thawing. The Cmic and Nmic were negatively correlated to the soil temperature at the early stage of soil thawing, and exponentially related to the soil moisture content during the whole soil thawing period.

Soil microbial biomass |and |activity in relation to stand age of poplar shelterbelts.

2009, 20(09):  2079-2084. 

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Taking  5-, 10-, 15-, and 20 years old poplar (Populus euramericana cv. “N 3016”) shelterbelts in Jianping County, Liaoning Province as test objects, the effects of establishing shelterbelts on the farmland soil microbial biomass carbon and nitrogen, and microbial activity were evaluated. After the establishment of shelterbelts, the concentrations of organic carbon and total nitrogen, the microbial biomass carbon and nitrogen, and the basal respiration in 0〖KG-*2〗-〖KG-*7〗15 cm soil layer increased after an initial decrease, being reached or exceeded the levels of the control after 20 years afforestation. The metabolic quotient increased significantly after 5 years afforestation, but decreased with increasing stand age. All the results suggested that under the effects of shelterbelt establishment, farmland soil microbial biomass and activity had obvious change.

Effects of salt-alkali stress on osmoregulation substance and active oxygen metabolism of Qingshan poplar (Populus pseudo-cathayana × P. deltoides).

2009, 20(09):  2085-2091. 

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Aimed to examine the adaptability of Qingshan poplar (Populus pseudo-cathayana × P. deltoides) to salt-alkali stress, two-year-old cutting seedlings of the poplar were treated with 28 combinations of salt-alkali stress. With increasing salt concentration, the leaf electrolyte leakage and MDA and proline contents of test seedlings all showed an increasing trend, while the leaf soluble sugar content and SOD and POD activities increased first but decreased afterwards. The increase of substrate pH made the electrolyte leakage, MDA content, and POD activity increased and the proline and soluble sugar contents decreased after an initial increase, but had lesser effects on the SOD activity. When the salinity was < 100 mmol·L-1 and the pH was increasing, all test physiological indices had a slight change while SOD activity kept at a higher level; when the salinity was > 200 mmol·L-1 and the pH was higher than 8.99, the electrolyte leakage was higher than 50%, POD activity and MDA content increased obviously, proline and soluble sugar contents declined, and SOD activity was lower. It was concluded that a salt-alkali condition with salinity > 200 mmol·L-1 and pH >899 was not appropriate to the growth of Qingshan poplar.

Effects of simulated acid rain on Quercus glauca seedlings photosynthesis and chlorophyll fluorescence.

2009, 20(09):  2092-2096. 

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Taking the seedlings of Quercus glauca, a dominant evergreen broadleaf tree species in subtropical area, as test materials, this paper studied their photosynthesis, chlorophyll fluorescence, and chlorophyll content under effects of simulated acid rain with pH 25, 40, and 56 (CK). After 2-year acid rain stress, the net photosynthetic rate of Q. glauca increased significantly with decreasing pH of acid rain. The acid rain with pH 25 and 4.0 increased the stomatal conductance and transpiration rate, and the effect was more significant under pH 25. The intercellular CO2 concentration decreased in the order of pH 25>pH 56>pH 40. The maximum photosynthetic rate, light compensation point, light saturation point, and dark respiration rate were significantly higher under pH 25 and 40 than under pH 56, while the apparent quantum yield was not sensitive to acid rain stress. The maximal photochemical efficiency of PSⅡ and the potential activity of PSⅡ under pH 25 and 40 were significantly higher than those under pH 56. The relative chlorophyll content was in the order of pH 25>pH 56>pH 40, and there was a significant difference between pH 25 and 40. All the results suggested that the photosynthesis and chlorophyll fluorescence of Q. glauca increased under the effects of acid rain with pH 25 and 40, and the acid rain with pH 25 had more obvious effects.

Physical and chemical properties of throughfall in main forest types of secondary forest ecosystem in montane regions of eastern Liaoning Province, China.

2009, 20(09):  2097-2104. 

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From July to September 2008, a measurement was made on the physical an
d chemical properties of bulk precipitation and throughfall in five main forest
types, i.e., larch plantation (LP), Fraxinus rhynchophylla stand (FR), mixed for
est stand (MF), Korean pine plantation (KP), and Mongolian oak stand (MO), of se
condary forest ecosystem in montane regions of eastern Liaoning Province, China.
 Comparing with bulk precipitation, the throughfall in the five forest types was
 significantly acidified (P＜005), and the acidification degree was in the
 order of KP>LP>MF>MO>FR. The conductivity and total dissolved solids of the
throughfall increased significantly (P＜005), and were in the sequence of
MO>FR>LP>MF>KP. The dissolved oxygen  concentration of the throughfall lowere
d significantly (P＜005), with the rank of KP>MF>FR>MO>LP, while the Cl-
 concentration increased significantly, ranked as LP>MO>MF>FR>KP. The NO3- c
oncentrations of the throughfall in FR, MO and MF were higher, while those in LP
 and KP were lower than that of the bulk precipitation.

Responses of spatial distribution pattern of Artemisia ordosica population to the precipitation gradient on Ordos Plateau.

2009, 20(09):  2105-2110. 

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Five sites along the precipitation gradient (336〖KG-*2〗-〖KG-*7〗24
9 mm·a-1) from east to west in Ordos Plateau were selected to study the spat
ial distribution pattern of Artemisia ordosica population and its responses
to the precipitation gradient by the methods of variance mean ratio, aggregative
 index, and point pattern analysis. The reduction of precipitation affected the
spatial distribution pattern of A. ordosica population significantly. With d
ecreasing precipitation gradient, the spatial pattern of A. ordosica populat
ion changed from uniform to random in small scale, and from random to clumpy in
large scale, suggesting that in the ecological restoration of Ordos Plateau, a r
ational arrangement of A. ordosica should be made.

Time lag characteristics of stem sap flow of common tree species during their growth season in Beijing downtown.

2009, 20(09):  2111-2117. 

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From April to September in 2008, the stem sap flow velocity (Js) of se
veral common tree species (Ginkgo biloba, Aesculus chinensis, Magnolia denudata,
 Robinia pseudoacacia, Pinus tabulaeformis and Cedrus deodara) in Beijing was m
easured by thermal dissipation method. Cross-correlation analysis was used to e
stimate the time lag between the stem sap flow and the driving factors of canopy
 transpiration among the tree species. The Js of the six tree species was
significantly correlated with the total radiation (Rs) and vapor pressure
deficit (D), and the Js was lagged behind Rs but ahead of D.
 The maximum correlation coefficient of Js with Rs (074〖KG-*2〗-
〖KG-*7〗093) was often higher than that of Js with D (057〖KG-*2
〗-〖KG-*7〗079), indicating that the diurnal Js was more dependent on
Rs than on D. The sampled tree species except P. tabulaeformis had a
shorter time lag of Js with Rs (10〖KG-*2〗-〖KG-*7〗70 min)
than with D (47〖KG-*2〗-〖KG-*7〗130 min), and there existed significant di
fferences among R. pseudoacacia, P. tabulaeformis, and C. deodara. The t
ime lag between the Js and the driving factors of canopy transpiration was
 mainly correlated with the tree features (DBH, tree height, canopy area, and sa
pwood area) and the nocturnal water recharge, regardless of tree species.

Effects of inoculating AM fungi on physiological characters and nutritional components of Astragalus membranaceus under different N application levels.

2009, 20(09):  2118-2122. 

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A pot culture with unsterilized soil as growth substrate showed that AM fungi had significant effects on the growth of Astragalus membranaceus (Fabaceae) under different N application levels. Inoculation with AM fungi promoted the AM infection of A. membranaceus roots, but high N application level suppressed the infection. Inoculating AM fungi increased the growth rate, soluble protein and sugar contents, and SOD, POD and CAT activities of A. membranaceus. Under 50 and 100 mg·kg-1 of N application, new bands of POD isozyme occurred in inoculated plants, and the contents of flavonoid, N, and P in A. membranaceus also had definite increase. The best inoculation effect was observed under the N application level of 50〖KG-*2〗-〖KG-*7〗100 mg N·kg-1 soil.

Characteristics of Stipa grandis growth and reproductive biomass allocation at different hill position of Xilingol grassland, Inner Mongolia.

2009, 20(09):  2123-2128. 

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An investigation was conducted on the vegetative and reproductive biom
ass allocation of Stipa grandis at the hill-top and hill-foot of Xilingol
grassland, and relatedness- and factor analyses were made to study the effects
of hill position on the S. grandis seed biomass. Significant differences were ob
served in the vegetative and reproductive growth of S. grandis plants at the
 hill-top and hill-foot. At hill-foot, the height and number of non-flowerin
g S. grandis ramets increased by 2469% and 3537%, respectively, the number o
f flowering ramets increased by 10297%, the vegetative, reproductive, and tota
l biomass increased by 4414%, 9559% and 4745%, respectively, and the
100-grain mass increased by 2500%, as compared with those at hill-top. The
 seed biomass of S. grandis at hill-top was mainly affected by soil moistur
e content, while that at hill-foot was mainly affected by soil pH. Hill positio
n induced the differentiation of soil moisture and N contents, and made the
S. grandis at the fertile hill-foot allocating more energy to its sexual re
production.

Effects of climate change on photosynthesis of Diospyros kaki under different soil moisture conditions.

2009, 20(09):  2129-2134. 

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Taking two-year-old Diospyros kaki as test material, this paper studied the effects of high CO2 concentration (700 μmol·mol-1), high temperature (5 ℃ higher than the mean daily temperature), and their combination on the net photosynthesis rate (Pn), evapotranspiration (Tr), stomatal conductance (Gs), water use efficiency (WUE), chlorophyll content, Fv/Fm, and Fv/Fo under different soil moisture conditions, with the ambient air temperature and CO2 concentration (380 μmol·mol-1) as the control. Under all test soil moisture conditions, the combination of high CO2 concentration and high temperature decreased the Tr and Gs, but increased the WUE. This combination increased the Pn when the soil moisture content was 75%〖KG-*2〗-〖KG-*7〗85% and 55%〖KG-*2〗-〖KG-*7〗65% of field capacity, but decreased the Pn when the soil moisture content was 35%〖KG-*2〗-〖KG-*7〗45%. High CO2 concentration increased the Pn and WUE but decreased the Gs and Tr under all test soil moisture conditions. The effects of high temperature and its combination with high CO2 concentration on the WUE depended on soil moisture condition, with the WUE increased with increasing soil moisture content. Comparing with the control, high CO2 concentration also increased the leaf Chla, Chlb, Chl(a+b), and Car concentrations and the Fv/Fm and Fv/Fo values, relieved the water stress, and increased the stress-resistance of D. kaki.

Effects of early growth stage shading on rice flag leaf physiological characters and grain growth at grain-filling stage.

2009, 20(09):  2135-3141. 

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In a pot experiment, rice plants were shaded during the period from tr
ansplanting to booting, aimed to study the effects of early growth stage shading
 on the rice growth at grain-filling stage. Comparing with the control, early g
rowth stage shading decreased the tiller number by 2672%, but increased the fl
ag leaf area and soluble sugar content by 3386% and 3023%, respectively. The
 filled-grain number per panicle, 1000-grain mass, ultimate brown rice mass,
  and maximum and average grain-filling rates decreased by 865%, 481%, 97
4%, 2022%, and 1913%, and the effective panicle number and grain yield decli
ned by 2526% and 3956%, respectively. The peak time of grain-filling rate (Tm) advanced 166 days, while the grain-filling time  (T99) prolonged 680 da
ys. For shading-tolerance variety, its flag leaf Chl a, Chl b, and Chl (a+b) co
ntents at early and mid grain-filling stages, and the protein N and soluble su
gar contents and Chl a/b in its flag leaves at grain-filling stage all increase
d under early growth stage shading, and the ultimate brown rice mass and 1000-g
rain mass maintained at the similar levels as the control. Consequently, its grain yield reduction rate was lower than that of shading-sensitive variety.

Phosphorus use efficiency of wheat on three typical farmland soils under long-term fertilization.

2009, 20(09):  2142-2148. 

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Field experiments were conducted on three typical farmland soils (loess soil, fluvo-aquic soil, and cinnamon fluvo-aquic soil) in Northern China to study the grain yield, phosphorus agronomic efficiency (PAE), and phosphorus use efficiency (PUE) of wheat under effects of long-term fertilizations. Seven treatments were installed, i.e., non-fertilization (CK), nitrogen fertilization (N), nitrogen-potassium fertilization (NK), nitrogen-phosphorus fertilization (NP), nitrogen-phosphorus-potassium fertilization (NPK), NPK plus straw returning (NPKS), and NPK plus manure application (NPKM). The averaged wheat grain yields under long-term P fertilizations (treatments NP, NPK, NPKS, and NPKM) ranged from 2914 kg·hm-2 to 6219 kg·hm-2, being 200%〖KG-*2〗-〖KG-*7〗400% higher than those under no P fertilizations (treatments CK, N, and NK), and no significant differences were observed between the P fertilizations. In the early years of the experiment, the PAE in treatment NPK on the loess soil, fluvo-aquic soil, and cinnamon fluvo-aquic soil was 170 kg·kg-1, 203 kg·kg-1, and 133 kg·kg-1, and the PUE was 153%, 312%, and 238%, respectively. After 15-year fertilization, the PAE and PUE in treatment NPK increased annually by 39 kg·kg-1 and 13% on loess soil, 25 kg·kg-1 and 09% on fluvo-aquic soil, and 28 kg·kg-1 and 10% on cinnamon fluvo-aquic soil, respectively. There were no significant differences in the PAE and PUE among the P treatments for the same soils. In Northern China, long-term P fertilization could increase the wheat grain yield and PUE significantly, and the mean annual increase of PAE and PUE in treatment NPKM was higher on loess soil than on fluvo-aquic soil and cinnamon fluvo-aquic soil.

Effects of water stress on protein expression and physiological properties of different genotype wheat (Triticum aestivum L.) sprouts.

2009, 20(09):  2149-2156. 

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With drought-resistant wheat (Triticum aestivum) cultivar Changw
u 134 and drought-sensitive cultivar Zhengyin 1 as test materials, and by using
-12 MPa PEG 6000 to treat their seeds, this paper studied the protein express
ion and physiological properties of the sprouts under different soil moisture co
nditions. SDS-PAGE analysis showed that water stress induced the production of
two new proteins with molecular weights of 395 kDa and 230 kDa in Changwu
134 but not in Zhengyin 1 sprouts. Under normal water supply, the expression of
the protein with molecular weight of 485 kDa in the sprouts of both Changwu 13
4 and Zhengyin 1 increased with sprout growth. This protein was preliminarily na
med as water-sensitive protein, due to its water-sensitivity and of newly disc
overed protein. The determinations of physiological properties showed that under
 water stress, the sprouts of drought-resistant Changwu 134 had higher root/sho
ot ratio and higher relative water content, but lower relative membrane permeabi
lity and lower malondlaldehyde content than those of drought-sensitive Zhengyin
 1.

Low-temperature responses of enzyme activities related to fiber development of two cotton (Gossypium hirsutum L.) cultivars with different temperature-sensitivity.

2009, 20(09):  2157-2165. 

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Taking two cotton cultivars with different temperature-sensitivity during their fiber strength formation as test materials, a field experiment of different sowing dates was conducted in Nanjing of Jiangsu Province in 2006 and 2007 to study the effects of low temperature on the activities and gene expression of the enzymes related to fiber development. The low temperature induced by late sowing (with the mean daily minimum temperature being 211, 205, and 181 ℃ during fiber development period) had definite effects on the enzyme activities, and accordingly, the fiber strength formation. Low temperature increased the invertase and β-1,3-glucanase activities, decreased the sucrose synthase and sucrose phosphate synthase activities, prolonged the time with higher gene expression level of Expansin and sucrose synthase, and delayed the expression peak and decreased the gene expression quantity of β-1,3-glucanase. There existed significant differences in the low-temperature responses of related enzymes activities between the two cultivars, with the change ranges of the enzyme activities being larger for temperature-sensitive cultivar Sumian 15 than for temperature-insensitive cultivar Kemian 1, which could be the main reasons leading to the different temperature-sensitivity of the two cotton cultivars during their fiber strength formation.

Effects of no-tillage and fertilization on paddy soil CH₄ and N₂O emissions and their greenhouse effect in Central China.

2009, 20(09):  2166-2172. 

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By using static chamber-gas chromatographic techniques, the CH4 and N2O emissions from the paddy soil in southeast Hubei were measured. Four treatments were installed, i.e., no-tillage plus no-fertilization (NT0), conventional tillage plus no-fertilization (CT0), no-tillage plus fertilization (NTC), and conventional tillage plus fertilization (CTC). In all treatments, the CH4 emission had a seasonal variation of increasing first and decreasing then, while the N2O emission had no significant seasonal variation. Fertilization increased the CH4 and N2O emissions significantly. NT0 increased the CH4 emission and decreased the N2O emission significantly, compared with CT0; NTC only decreased the CH4 emission and increased the N2O emission slightly, compared with CTC. The analysis on the integrated greenhouse effect of CH4 and N2O showed that NT0 increased the effect by 259%, compared with CT0, while NTC decreased the effect by 101%, compared with CTC. Therefore, a reasonable arrangement of fertilization and no-tillage could reduce the integrated greenhouse effect of CH4 and N2O from paddy field.

Effects of different tillage measures on upland soil respiration in Loess Plateau.

2009, 20(09):  2173-2180. 

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A field experiment was conducted in Lijiabu Town of Dingxi City, Gansu
 Province to study the soil respiration and its relations with the canopy temper
ature and soil moisture content in a rotation system with spring wheat and pea u
nder effects of different tillage measures. Six treatments were installed, i.e.,
 tillage with no straw- or plastic mulch (conventional tillage, T), tillage wit
h straw mulch (TS), tillage with plastic mulch (TP), no-tillage (NT), no-tilla
ge with straw mulch (NTS), and no-tillage with plastic mulch (NTP). During the
growth periods of spring wheat and pea, soil respiration had different change pa
tterns, with the peaks appeared at the early jointing, grain-filling, and matur
ing stages of spring wheat, and at the 5-leaf, silking, flowering and poding, a
nd maturing stages of pea. There was an obvious difference in the diurnal change
 of soil respiration in spring wheat field between treatments NTS and T, and the
 soil respiration rate was significantly lower in NTS than in T; while the soil
respiration in pea field had less diurnal change. Soil respiration rate had a si
gnificant linear relationship with the canopy temperature of both spring wheat a
nd pea, the correlation coefficient being the highest at booting stage of spring
 wheat and at flowering and poding stage of pea, followed by at grain-filling s
tage of spring wheat and at branching stage of pea. There was also a significant
 parabola relationship between soil respiration rate and soil moisture content,
the correlation coefficient being higher under conservation tillage than under c
onventional tillage, with the highest under NTS. The moisture content in 10〖KG-*2〗-〖KG-*7〗30 cm soil layer of spring wheat field and that in 5〖KG-*2〗-〖KG-*7〗10 cm soil layer of pea field h
ad the greatest effects on soil respiration. Comparing with conventional tillage
, all the five conservation tillage measures decreased soil respiration, with th
e best effects of no-tillage with straw mulch.

Responses of enzyme activities in different particle-size aggregates of paddy soil in Taihu Lake region of China to long-term fertilization.

2009, 20(09):  2181-2186. 

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Taking a long-term fertilized paddy soil in Taihu Lake region as research object, the enzyme activities in <2, 2〖KG-*2〗-〖KG-*7〗20, 20〖KG-*2〗-〖KG-*7〗200, and 200〖KG-*2〗-〖KG-*7〗2000 μm aggregates under no fertilization (NF), chemical fertilization (CF), chemical fertilization plus straw return (CFS), and chemical fertilization plus pig manure (CFM) were investigated. Fertilization promoted the formation of 200〖KG-*2〗-〖KG-*7〗2000 μm aggregates significantly. The enzyme activities differed with aggregates’ particle-size. Urease and invertase activities were the highest in <2 μm aggregates, whereas the activities of cellulase, polyphenoloxidase and FDA hydrolase were the highest in 200〖KG-*2〗-〖KG-*7〗2000 μm aggregates. Fertilization, especially the combined fertilization of inorganic and organic fertilizers, increased the activities of urease, invertase, cellulase and FDA hydrolase in 200〖KG-*2〗-〖KG-*7〗2000 μm aggregates significantly. With the geometric mean (GMea) of the five test enzyme activities as the integrative index of soil enzyme activities, it was found that under fertilization, the GMea was significantly higher in 200〖KG-*2〗-〖KG-*7〗2000 μm aggregates, suggesting the high sensitivity of enzyme activities in larger particle-size aggregates to fertilization practices. Long-term inorganic plus organic fertilization could enhance the soil bio-function via the promotion of the formation of larger particle-size aggregates and the enzyme activities in these aggregates.

Soil enzyme activities under different restoration modes after returning farmland to lake in Dongting Lake area.

2009, 20(09):  2187-2192. 

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To reveal the effects of different restoration modes after returning farmland to lake on the soil biological characteristics in Dongting Lake area, the activities of soil saccharase, urease, phosphatase, and catalase at three typical sites (Xiaojicheng, Guanyuan, and Qingshanyuan) were studied. At the Xiaojicheng site where poplar was planted, soil catalase activity increased significantly, but the activities of other three test enzymes had no significant change. At the Guanyuan site where reed was planted, the activities of soil saccharase and phosphatase had somewhat decrease, and those of urease and catalase had less change. At the Qingshanyuan site where natural water area was restored, the test enzyme activities had less changes except that the phosphatase activity decreased. Correlation analysis showed that the test enzyme activities had significant positive correlations with soil organic matter content (P<001), illustrating that the changes in the soil organic matter content under different restoration modes could be the main cause inducing the changes in soil enzyme activity.

Effects of bio-crust on soil microbial biomass and enzyme activities in |copper mine tailings.

2009, 20(09):  2193-2198. 

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Bio-crust is the initial stage of natural primary succession in  copper mine tailings. With the Yangshanchong and Tongguanshan copper mine tailings in Tongling City of Anhui Province as test objects, this paper studied the soil microbial biomass C and N and the activities of dehydrogenase, catalase,
alkaline phosphatase, and urease under different types of bio-crust. The bio-c
rusts improved the soil microbial biomass and enzyme activities in the upper lay
er of the tailings markedly. Algal crust had the best effect in improving soil m
icrobial biomass C and N, followed by moss-algal crust, and moss crust. Soil mi
croflora also varied with the type of bio-crust. No significant difference was
observed in the soil enzyme activities under the three types of bio-crust. Soil
 alkaline phosphatase activity was significantly positively correlated with soil
 microbial biomass and dehydrogenase and urease activities, but negatively corre
lated with soil pH. In addition, moss rhizoid could markedly enhance the soil mi
crobial biomass and enzyme activities in moss crust rhizoid.

Characteristics of agricultural climate resources in three provinces of Northeast China under global climate change.

2009, 20(09):  2199-2206. 

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Based on the 1961〖KG-*2〗-〖KG-*7〗2007 weather data from 72 meteorol
ogical stations in three provinces of Northeast China, the change characteristic
s of agricultural climatic factors including yearly and temperature-defined growing season’s  mean air
 temperature, ≥10 ℃ accumulated temperature, precipitation, reference evapotranspiration, and sunshine hours were analyzed. In 1961〖KG-*2〗-〖KG-*7〗2007, the
 yearly mean air temperature in the three provinces had an increasing trend, wit
h a rate of 038 ℃·10 a-1. The ≥10 ℃ accumulated temperature in temperature-defined growing season also had an increasing trend, and the border of ≥10 ℃ accumulated temperature belt moved northward and eastward. The area of ≥3200 ℃·d accumulated temperature increased by 22×104 km2. The belt of 2800〖KG-*2〗-〖KG-*7〗320
0 ℃·d moved northward about 085° and eastward about 067°, while that o
f 2400〖KG-*2〗-〖KG-*7〗2800 ℃·d moved northward about 11°. The sunshine h
ours decreased significantly, especially in the east part of Songnen Plain, cent
ral and west plains of Jilin Province, and west part of Liaohe River Plain. The ar
ea with sunshine hours > 2800 h decreased from 136×104 km2 to 41×104
 km2, and the zone with sunshine hours 2600〖KG-*2〗-〖KG-*7〗2800 h moved wes
tward about 15°. The average sunshine hour in temperature-defined growing season was 1174 h. Comparing with that in 1961〖KG-*2〗-〖KG-*7〗1980, the region with more sunshine
hours in temperature-defined growing season in 1981〖KG-*2〗-〖KG-*7〗2007 narrowed significan
tly, and the zone with sunshine hours 1200〖KG-*2〗-〖KG-*7〗1400 h moved westwa
rd about 09°. In 1961〖KG-*2〗-〖KG-*7〗2007, both the yearly and the
temperature-defined growing season’s precipitation decreased, and the yearly reference evapotranspiration i
ncreased in Heilongjiang Province and in the eastern mountain areas of Jilin Pro
vince but decreased in the central and west plains of Jilin Province and in Liao
ning Province. Comparing with that in 1961〖KG-*2〗-〖KG-*7〗1980, the zone of r
eference evapotranspiration with the value of ≥900 mm in 1981〖KG-*2〗-〖KG-*7
〗2007 moved westward about 1°, and the reference evapotranspiration in
temperature-defined growing season increased in most regions of Heilongjiang and Jilin Province but decrease
d in a rate of 0〖KG-*2〗-〖KG-*7〗14 mm·10 a-1 in most regions of Liaoni
ng Province.

Effects of nitrogen supply level on microbial transformation of amino sugar in a mollisol amended with maize straw.

2009, 20(09):  2207-2213. 

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A 38-week laboratory incubation test at 25 ℃ was conducted to examine the effects of different inorganic N supply level (0, 603, 1672, and 7019 mg N·kg-1 soil, noted as N0, Nlow, Nmid, and Nhig, respectively) on the microbial transformation of amino sugar in a mollisol amended with maize straw. Comparing with the control, the amendment of maize straw promoted the microbial synthesis of amino sugar, and at the early period of incubation, the total amount of soil amino sugar increased with increasing inorganic N supply, being significantly higher in treatments Nmid and Nhig than in treatments N0 and Nlow. With prolonged incubation time, the total amount of soil amino sugar decreased, and the decrement was higher in treatments N0 and Nlow than in treatments Nmid and Nhig. Different inorganic N supply level also had different effects on the dynamics of various amino sugars. Muramic acid exclusively originated from bacteria was more easily to be affected by the inorganic N supply, compared with the glucosamine from fungal cell wall residues. For the amendment of higher C/N maize straw, a sufficient N supply would be necessary for the promotion of the accumulation and transformation of soil amino sugar. Soil N deficiency would restrict the growth of soil microbes, weaken the microbial synthesis of amino sugar, and decrease the captured N in microbial biomass, being not beneficial to the soil N accumulation.

Ecological security assessment of Tangshan City based on emergy analysis.

2009, 20(09):  2214-2218. 

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Based on ‘pressure-state-response’ model and by using emergy analy
sis method, the urban ecological security assessment system and urban ecological
 security index (EUESI) were constructed, and the variation of ecological securi
ty level of Tangshan City in 1995〖KG-*2〗-〖KG-*7〗2005 was evaluated. During t
his period, the ecological security level of the City increased first and decrea
sed then. The EUESI increased from 0017 in 1995 to 0022 in 1996, then droppe
d yearly, and became unsecure in 2003. The urban ecological security assessment
method based on emergy analysis overcame the disadvantages of conventional asses
sment system, e.g., numerous and repetitive indicators, non-uniform units, and
poor comparability, and reflected the urban ecological security state more objec
tively, being able to provide scientific basis for urban ecological environment
management and decision-making.

Ecological safety assessment of Manas River Basin oasis, Xinjiang.

2009, 20(09):  2219-2224. 

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By using analytic hierarchy process and fuzzy comprehensive evaluation
, an index system for ecological safety assessment was built, and 18 indices in
the aspects of water resource, environment, and social economy were selected to
assess the ecological safety of Manas River Basin oasis in 2006. In the study ar
ea, the ecological situation in 2006 was basically safe, with the membership deg
ree being 03347 and the integrated evaluation score being 0551. The water re
source safety index, social economy index, and environmental safety index were i
n the levels of relatively safe, extremely safe, and unsafe, respectively. Water
 resource index could represent the sustainable development degree of oasis, whi
le social economy index and environment safety index could indicate the oasis de
velopment level and environment situation, respectively. These three indices cou
ld most reflect the ecological safety level of the oasis.

Ecosystem service valuation of Ertan Reservoir watershed in mitigating reservoir sand sedimentation.

2009, 20(09):  2225-2232. 

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By using software ArcGIS 92, an evaluation model was established to
simulate the ecosystem service of Ertan Reservoir watershed in mitigating the sa
nd sedimentation in the reservoir. In the meantime, sediment delivery ratio and
universal soil loss equation were used to simulate the spatial patterns of the a
nnual sediment yield and sediment retention in the watershed as well as the  value during the service life period. In 2000, the total quantity of soil r
etention in the watershed was 121×108 t·a-1. The region with higher
 soil retention was near the main and branch streams of Yalong River, and that w
ith higher sediment delivery ratio was near the streams and the Ertan Reservoir.
 The region with higher sediment yield and sediment retention was around the res
ervoir. The actual sediment yield in the study area was 6293×104 t·a-
1, occupying 127% of the actual soil erosion volume. Farmland was the most i
mportant source of sediment yield, with its sediment yield occupying 629% of t
he total. The contribution of forestland to the mitigation of reservoir sand sed
imentation was higher than that of the other lands on a per unit area basis. For
 the reservoir’s designed operating life (100 a), the total  value of th
e watershed in the service of mitigating Ertan Reservoir sand sedimentation was
275 billion yuan.

Simulation and prediction of water environmental carrying capacity in Liaoning Province based on system dynamics model.

2009, 20(09):  2233-2240. 

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By the methods of system dynamics, a water environmental carrying capa
city (WECC) model was constructed, and the dynamic trend of the WECC in Liaoning
 Province was simulated by using this model, in combining with analytical hierar
chy process (AHP) and the vector norm method. It was predicted that under the co
nditions of maintaining present development schemes, the WECC in this province i
n 2000〖KG-*2〗-〖KG-*7〗2050 would be decreased year after year. Only increasin
g water resources supply while not implementing scientific and rational manageme
nt of water environment could not improve the regional WECC, and the integration
 of searching for new and saving present water resources with controlling wastew
ater pollution and reducing sewage discharge would be the only effective way to
improve the WECC and the coordinated development of economy, society, and enviro
nment in Liaoning.

Transpiration of Brassica chinensis L. in a plastic greenhouse covered with insect-proof nets in lower reaches of Yangtze River: A simulation study.

2009, 20(09):  2241-2248. 

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With the climate data inside and outside a plastic greenhouse as driving variables, and the greenhouse structure, insect-proof net material, and characteristic breadth and leaf area index of Brassica chinensis L. as parameters, a canopy transpiration model for greenhouse B. chinensis was established, based on Penmam-Monteith transpiration model. This established model was validated by the experimental data of independent samples in a single greenhouse. The results showed that in lower reaches of Yangtze River, the vent discharge coefficient (Cd) of greenhouse covered with 20-, 25-, and 28- mesh insect-proof nets was 0771, 0758 and 0736, and the wind pressure coefficient (Cw) was 033, 037, and 039, respectively. The determination coefficient (R2) between the predicted and measured canopy transpiration rate for the sunny, cloudy, and overcast days in summer was 095, 091, and 094, root mean squared error (RMSE) was 0018, 0014, and 0015 g·m-2·s-1, and relative prediction error (RE) was 1427%, 1805%, and 1580%, respectively, suggesting that this model could better predict the transpiration rate of B. chinensis in the plastic greenhouse covered with insect-proof nets in lower reaches of Yangtze River.

Effects of host plants on selection behavior and biological parameters of Bemisia tabaci Gennadius biotype B.

2009, 20(09):  2249-2254. 

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Based on the observation of free diffusion in petri dish and biology, the selectio
n behavior and biological parameters of Bemisia tabaci Gennadius biotype B o
n host plants cucumber, eggplant, pepper, cotton, and sweet potato were invest
igated. No difference was observed in the individual number of B. tabaci on
the five host plant leaves during the early period of free diffusion (within 2 h
), but changes were found within the following periods (4〖KG-*2〗-〖KG-*7〗48 h), i.e., the B.
 tabaci individuals increased on cucumber, decreased on pepper, and were rel
atively stable on eggplant, cotton, and sweet potato, which indicated that there
 were significant differences in the selectivity of B. tabaci on the five ho
st plants, with the highest selectivity to cucumber and the lowest selectivity t
o pepper. Pretreatment by starvation and imidacloprid did not affect the selec
tivity of B. tabaci. There were significant differences on the honeydew excr
etion of female B. tabaci adults on the host plants, which was in the order
of cucumber>sweet potato>cotton>eggplant>pepper. The average longevity of B.
tabaci adults on cucumber, eggplant, sweet potato, and cotton was significantl
y longer than that on pepper, and the total number of eggs laid per female on
cucumber, eggplant, sweet potato, and cotton (22433, 18233, 19173, and 172
60 respectively) was significantly larger than that on pepper (only 4783).
 No significant differences were observed in the hatching rate and development p
eriod of the eggs on the five host plants. The development period of nymphs on c
ucumber, eggplant, sweet potato, and cotton was 1060 d, 1196 d, 1111 d, and 1320 d, and the mortality was 521%, 2778%, 1724%, and 3711%, respective
ly. The nymphs failed to develop normally on pepper.

Relationships between island characteristics and arthropod diversity in Thousand-island Lake.

2009, 20(09):  2255-2261. 

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In April, May, August, and October 2006, grid-based sampling method w
as adopted to investigate the diversity and abundance of arthropods on 50 island
s in the Thousand-island Lake, with the effects of island area, island altitude
, island shape, inter-island distance, and island-mainland distance on arthrop
od species richness analyzed. With the increase of island area, the richness of
total arthropod species and that of the arthropod species with high- and low-
dispersal ability all increased, and the relationships between island area and a
rthropod species richness corresponded to the classical island biogeography mode
l. The island area, island altitude, and island shape had comprehensive effects
on the arthropod species richness, while inter-island distance and island-main
land distance had less effects. The richness of total arthropod species had a
significant positive correlation with island altitude and island shape, that of
the arthropod species with high- dispersal ability was significantly positively
 correlated with island area and island altitude, while no significant relations
hip was observed between the richness of arthropod species with low-dispersal a
bility and the island characteristics.

Vertical distribution and community diversity of butterflies in Yaoluoping National Nature Reserve, Anhui, China.

2009, 20(09):  2262-2270. 

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By the methods of fixed point, line intercept, and random investigation, the vertical distribution and community diversity of butterflies in Yaoluoping National Nature Reserve were investigated from 2005 to 2008. A total of 3681 specimen were collected, belonging to 111 species, 69 genera, and 10 families, among which, Nymphalidae had the higher species number, individual’s number, and diversity index than the other families. The butterflies in the study area were a mixture of Oriental and Palaearetic species, with the Oriental species diminished gradually and the Palaearetic components increased gradually with increasing altitude. Among the three vertical zones (< 800 m, 800〖KG-*2〗-〖KG-*7〗1200 m, and >1200 m in elevation), that of 800〖KG-*2〗-〖KG-*7〗1200 m had the most abundant species of butterflies; and among the six habitat types
(deciduous broad-leaved forest, evergreen conifer forest, conifer-broad leaf mixed forest, bush  and secondary forest, farmland, and residential area), bush and  secondary forest had the higher species number, individual’s number, and diversity index of butterflies, while farmland had the lowest diversity index. The similarity coefficient of butterfly species between the habitats was mainly dependent on vegetation type, i.e., the more the difference of vegetation type, the lesser the species similarity coefficient between the habitats, which was the highest (061) between conifer-broad leaf mixed forest and bush and secondary forest, and the lowest (020) between evergreen conifer forest and bush and secondary forest.

Distribution patterns of giant panda in Guanyinshan and Foping nature reserves.

2009, 20(09):  2271-2276. 

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By using line transect method, the distribution patterns of giant pand
a population and its sympatric companion wildlife species in Foping and Guanyins
han nature reserves were investigated in October 2007 and April 2008, and the en
vironmental factors affecting the spatial distribution of giant panda activity w
ere analyzed. The giant panda population and its sympatric companion wildlife sp
ecies in the two reserves had the similar distribution patterns, and the density
 and distribution range of giant panda were smaller in Guanyinshan than in Fopin
g. Giant panda had two high-density distribution areas in Foping, but no activi
ty trace in most parts of Guanyinshan. The activity trace of Budorcas taxicolo
r, Naemorhedus goral and Sus scrofa was more in Guanyinshan than in Foping
. Anthropogenic interference might affect the distribution pattern of giant pand
a.

Inhibitory effects of dry Acorus calamus extracts on the growth of two water bloom-forming algal species.

2009, 20(09):  2277-2282. 

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A trial with different concentrations of aqueous extracts from dry Acorus calamus plants  was conducted to study the effects of the extracts on Microcystis aeruginosa and Chlorella pyrenoidosa growth. Allelopathic effects were observed. H
igh concentration (>40 ml·L-1) extracts inhibited the growth of the two a
lgal species at low inoculation cell density significantly (P<001), with t
he maximal inhibition rate being 98.66% for M. aeruginosa and 9238% for
C. pyrenoidosa, while low concentration (<30 ml·L-1) extracts promote
d the growth of C. pyrenoidosa. Neither high nor low concentration extracts
had significant effects on the growth of the two algal species at high inoculati
on cell density (P>005). The comparison of adding the aqueous extracts onc
e and semi-consecutively showed that the allelochemicals in the extracts were e
asy to be degraded, suggesting that the continuous secretion of allelochemicals
in natural water bodies could play an important role in inhibiting algal growth.

Physiological responses of Myriophyllum spicatum to ammonium nitrogen.

2009, 20(09):  2283-2288. 

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With the sediment applied with 0, 024%, and 048% NH4Cl (treatme
nts CK, SN1, and SN2) as the substrate, a greenhouse experiment was conducte
d to study the physiological responses of Myriophyllum spicatum to ammonium nitr
ogen. The NH4+-N concentration in the sediment, pore-water, and overlying
-water ranged in 1235〖KG-*2〗-〖KG-*7〗87032 mg·kg-1, 109〖KG-*2
〗-〖KG-*7〗103605 mg·L-1, and 010〖KG-*2〗-〖KG-*7〗2430 mg·L-1
, respectively. Comparing with those in CK, the plant height, root length, and
 fresh biomass of M. spicatum in treatments SN1 and SN2 decreased by 15
66% and 5552%, 4572% and 6765%, and 1969% and 8116%, respectively. T
he SOD activity in M. spicatum leaves and roots was SN1<SN2<CK, but the
peroxidase (POD) and catalase (CAT) activities in the leaves were SN2<SN1<CK， while those in the roots were significant higher in SN1 and SN2 than in CK.
 The malondialdehyde (MDA) contents of leaves and roots in SN1 and SN2 were
increased by 4630% and 8275%, and 1966% and 5519%, respectively. It was
suggested that NH4+-N had toxic effects on M. spicatum, and the higher
the NH4+-N concentration in sediment, the more obvious the physiological re
sponses of M. spicatum exhibited.

Low water temperature tolerance and responding mode of scleractinian corals in Sanya Bay.

2009, 20(09):  2289-2295. 

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In an experimental temperature-regulated mesocosm, the low water temp
erature tolerance of five dominant scleractinian coral species Pavona decussat
e, Acropora pulchra, Acropora florida, Acropora valida, and Porites lutea
in Sanya Bay was investigated, and their responding modes to the cold water st
ress were analyzed. The tolerance of test corals to low water temperature was cl
osely related to their morphologies, with the branching corals being the most vu
lnerable to bleaching and death by separating the symbiotic polyps from their sk
eletons. The lethal low water temperature for branching Acropora corals was 14
℃ lasting for 3 days, and that for foliose P. decussate was 12 ℃ lasting f
or 10 days. Massive P. lutea corals responded to low water temperature by fo
rming mucus membrane, which helped to prevent the further losing of symbiotic al
gae. The corals showing strong tolerance to high water temperature also had stro
ng tolerance to low water temperature, and had similar responding modes to both
high and low water temperature, i.e., the corals didn’t extend their tentacl
e first, followed by the continuous release of mucus and the discharge of symbio
tic zooxanthellae, and finally, bleached and died.

Ecotoxicolgical effects of albendazole on Eisenia fetida.

2009, 20(09):  2296-2300. 

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By using artificial soil test, the effects of different concentration
albendozole on Eisenia foetida’s growth, survival, reproduction, and activities
 of superoxide dismutase (SOD), glutathione-sulfurtransferase (GST-S) and acet
ylcholine esterase (AchE) were studied. Low concentration (5 mg·kg-1)  albe
ndazole inhibited the reproduction of E. foetida significantly (P<005), an
d 7 mg·kg-1 of albendazole had significant effects on the growth and surv
ival of E. foetida. When the albendazole concentration reached to 10 mg·kg
-1, the mortality of E. foetida was as high as 53%. There was a signif
icant dose-response relationship between the exposure concentration of albendaz
ole and the inhibition rate of E. foetida’s growth and reproduction. After
21 days’ albendazole exposure, the SOD and GST-S activities were affected sign
ificantly, but no significant dose-response relationship was observed. Albendaz
ole exposure had less effects on AchE activity. In sum, albendazole had direct
 toxicity on soil animals, with a potential ecological risk.

Research advances in species diversity of arbuscular mycorrhizal fungi.

2009, 20(09):  2301-2307. 

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Arbuscular mycorrhizal (AM) fungi are one of the important components
of biodiversity in ecosystems. They are rich in species diversity, genetic diver
sity, and function diversity. Their taxonomy position moved forward to phylum, a
nd there are 214 species belonging to 19 genera, 13 families, 4 orders, and 1 cl
ass reported in the world. AM fungi play a vital role in keeping ecological bala
nce and enhancing ecosystem sustainable productivity. This paper reviewed the re
search advances in the species diversity of AM fungi distributed globally, the k
ey factors affecting this species diversity in various ecosystems, and related r
egulation pathways. It was considered that molecular biological techniques would
 be the main approaches in the future study of AM fungal species diversity.

Cyclic imine toxin gymnodimine: A review.

2009, 20(09):  2308-2313. 

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Gymnodimine (GYM), an algal toxin first detected from New Zealand oyst
ers in 1994, is identified as a cyclic imine toxin and produced by Karenia sel
liformis, with imino nitrogen attached on loop-coil. Imine is the poisonous f
unctional group of the toxin. GYM has a low oral toxicity, but its acute lethal
toxicity of intra-peritoneal injection for mice is very high. Up to now, few re
ports have been published on the detailed information about the toxicity mechani
sm of GYM. Based on limited literatures, this paper reviewed the GYM’s structure
, producer, toxicity mechanism, carrying animals, geological distribution, degra
dation metabolism, dose-effect relation, and risk evaluation, and proposed the
further research directions on algal toxin.