Table of Content

18 September 2011, Volume 22 Issue 09

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Articles

Effects of altitudinal gradient on water use efficiency of Betula ermanii on the northern slope of Changbai Mountains, Northeast China.

2011, 22(09):  2227-2232. 

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Taking Betula ermanii forests distributed at the altitudes 1800-2050 m on the northern slope of Changbai Mountains as test objects, and using leaf carbon isotope content (δ¹³C) as an indicator of B. ermanii water use efficiency (WUE), this paper studied the effects of altitudinal gradient on the WUE of B. ermanii forests in the area. With the increase of altitude, the soil volumetric water content  (VMC) and the leaf mass per area  (LMA) of B. ermanii increased significantly, while the leaf water content  (LWC) and soil temperature  were in adverse. There was a significant positive correlation between leaf δ¹³C and altitude, with the increment of leaf δ¹³C being 1.013‰·(100 m)^-1, and the leaf δ¹³C was positively correlated with soil VWC and LMA but negatively correlated with soil temperature and LWC. Temperature was not the sole limiting factor for the distribution of treeline in Changbai Mountains, whereas the physiological drought of B. ermanii during its growing season caused by the different water and heat conditions and their interactions along the altitudinal gradient could be the other limiting factors.

Water storage capacity of Qinghai spruce (Picea crassifolia) forest canopy in Qilian Mountains.

2011, 22(09):  2233-2239. 

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By the methods of direct measurement and regression analysis, this paper estimated the water storage capacity of Picea crassifolia forest canopy in Guantan  in Qilianshan Mountains, based on the observed throughfall and the laboratory experimental data about the water storage capacity of various canopy components in 2008. Due to the impacts of various factors, differences  existed in the canopy water storage capacity estimated by the two methods. The regression analysis was mainly impacted by the measurement approaches of the throughfall, the maximum water storage capacity estimated being 0.69 mm, whereas the direct measurement was mainly impacted by tree height, diameter at breast height, plant density, and leaf area index, with the estimated maximum water storage capacity being 0.77 mm. The direct measurement showed that the maximum water storage capacity per unit area of the canopy components of the forest was in the order of barks (0.31 mm) > branches (0.28 mm) > leaves (0.08 mm).

Effects of sandy land water habitat and years after rejuvenation pruning on leaf functional traits of Salix psammophila.

张萍萍,李秧秧,邵明安

2011, 22(09):  2240-2246. 

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This paper studied the effects of  habitats (riparian inter-dune and dry top dune) and years after rejuvenation pruning (1, 2, 3-4, and 5-6 years) on the leaf functional traits (gas exchange, water use efficiency, structural traits, and N and P contents) of Salix psammophila growing in the southern edge of Mu Us Sandy Land. In the habitat of riparian inter-dune, the leaf net photosynthetic rate, stomatal conductance, and instantaneous and long-term water use efficiencies were all higher, while the leaf N and P contents were lower, as compared with those in the habitat of dry top dune. No significant differences were observed in the leaf structural traits between the two habitats, suggesting that S. psammophila could survive in a dry habitat by the strategies of increasing nutrient uptake and decreasing photosynthesis and water use. With the increasing years after rejuvenation pruning, the leaf net photosynthetic rate and stomatal conductance decreased significantly, and the leaf N content and instantaneous water use efficiency also showed a decreasing trend, with a positive correlation between them. One-year after rejuvenation pruning, the leaf area was the highest, and the specific leaf mass and leaf dry matter content were the lowest. Thereafter, the leaf area and dry matter content had no obvious change, but the specific leaf mass increased with increasing years after rejuvenation pruning. There were no significant correlations between leaf structural traits and photosynthetic and nutrient traits, suggesting that the decreases of leaf photosynthetic capacity and N content were the major reasons for S. psammophila senescence with increasing years after rejuvenation pruning.

Soil moisture dynamics and water balance of Salix psammophila shrubs in south edge of Mu Us Sandy Land.

2011, 22(09):  2247-2252. 

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Taking the artificial sand-fixing Salix psammophila shrubs with different plant density (0.2, 0.6, and 0.8 plants·m^-2) in Mu Us Sandy Land as test objects, this paper studied the soil moisture dynamics and evapotranspiration during growth season. There existed obvious differences in the soil moisture dynamics and evapotranspiration among the shrubs. The soil moisture content changed in single-hump-shape with the increase of plant density, and in “S” shape during growth season, being closely correlated with precipitation. The evapotranspiration was the highest (114.5 mm) in the shrubs with a density 0.8 plants·m^-2, accounting for 90.8% of the total precipitation during growth season, and the lowest (109.7 mm) in the shrubs with a density 0.6 plants·m^-2. Based on the soil moisture dynamics and water balance characteristics, the appropriate planting density of  S. psammophila shrubs in Mu Us Sandy Land could be 0.6 plants·m^-2.

Variation  of soil organic carbon under different vegetation types in Karst mountain areas of Guizhou Province, Southwest China.

2011, 22(09):  2253-2258. 

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This paper studied the variation characteristics of soil organic carbon (SOC) and different particle sizes soil particulate organic carbon (POC) in normal soil and in micro-habitats under different vegetation types in typical Karst mountain areas of southwest Guizhou. Under different vegetation types, the SOC content in normal soil and in micro-habitats was all in the order of bare land < grass < shrub < forest, with the variation range being 7.18-43.42 g·kg^-1 in normal soil and being 6.62-46.47 g·kg^-1and 9.01-52.07 g·kg^-1 in earth surface and stone pit, respectively. The POC/MOC (mineral-associated organic carbon) ratio under different vegetation types was in the order of bare land < grass < forest < shrub. Under the same vegetation types, the POC/MOC in stone pit was the highest, as compared to that in normal soil and in earth surface. In the process of bare land-grass-shrub-forest, the contents of different particle sizes soil POC increased, while the SOC mainly existed in the forms of sand- and silt organic carbon, indicating that in Karst region, soil carbon sequestration and SOC stability were weak, soil was easily subjected to outside interference and led to organic carbon running off, and thus, soil quality had the risk of decline or degradation.

Responses of biological soil crust to and its relief effect on raindrop kinetic energy.

2011, 22(09):  2259-2264. 

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Based on the field investigation and by the method of simulated single-drop rain, this paper studied the responses of different types of biological soil crusts (biocrusts) in the wind-water erosion interleaving region of Loess Plateau to and their relief effect on the kinetic energy of raindrops. The responses of the biocrusts to raindrop kinetic energy had close relations with their biological composition. The cyanobacteria-dominated biocrusts with a thickness of 1 cm and the moss- dominated biocrusts with the coverage of 80% could resist in 0.99 J and 75.56 J of cumulative rain drop kinetic energy, respectively, and
 the potential resistance of the biocrusts with the same biological compositions was relative to the biomass of the biological compositions, i.e., the larger the biomass, the higher the resistance. As the chlorophyll a content of cyanobacteria- dominated biocrusts (which characterizes the cyanobacterial biomass) increased from 3.32 to 3.73 μg·g^-1, the resistance of the biocrusts against the cumulative raindrop kinetic energy increased from 0.99 to 2.17 J; when the moss biomass in the moss- dominated biocrusts increased from 2.03 to 4.73 g·dm^-2, the resistance of the crusts increased from 6.08 to 75.56 J. During the succession of the biocrusts, their responses to the raindrop kinetic energy presented an “S” pattern. No significant differences in the resistance against raindrop cumulative kinetic energy were observed between the cyanobacteria-dominated biocrusts with variable biomass, but the resistance of moss-dominated biocrusts increased significantly as their biomass per unit area increased. The resistance of moss-dominated biocrusts increased linearly when their biomass increased from 2.03 g·dm^-2 to 4.73 g·dm^-2. The moss-dominated biocrusts could resist in 62.03 J of raindrop kinetic energy when their biomass was up to 3.70 g·dm^-2. Biocrusts had obvious effects in relieving raindrop kinetic energy, and the relief effect increased with their increasing biomass.

Soil sandy desertification and salinization and their interrelationships in Yanghuang irrigated area of Hongsipu, Ningxia of Northwest China.

2011, 22(09):  2265-2271. 

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By the methods of controlled and typical sampling, this paper analyzed the texture, salinization characteristics, cation exchange capacity (CEC), and their correlations in the 0-40 cm soil profiles of corn land, medlar land, and non-utilized land in Yanghuang irrigated area of Hongsipu, Northwest China. Under controlled sampling, the salt content in the soil profiles was 0.69-1.30 g·kg^-1 (except in non-utilized land where the 0-10 cm soil salt content was up to 1.74 g·kg^-1), with no obvious salinization. The sodium adsorption ratio and exchangeable sodium percentage in the 20-40 cm soil layer of medlar land were 12.18 and 14.1%, respectively, and the total content of clay and silt in the 0-40 cm soil profile of medlar land was up to 37.3% whereas that in the 0-20 cm soil layer of corn land was only 13.5%. In the 20-40 cm soil layer of corn land, the indices of sandy desertification and salinization had significant correlations under controlled sampling but no correlations under typical sampling, while the CEC and the sandy desertification and salinization indices had significant correlations under typical sampling. In different land use types in the study area, soil sandy desertification and salinization had complicated interrelationships, and CEC could be used as the indicator for the changes in soil environmental quality.

Nutrient dynamics in Quercus mongolica leaves at different canopy positions. 

2011, 22(09):  2272-2278. 

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Taking the dominant tree species Quercus mongolica in natural coniferous-broadleaved mixed forest in Changbai Mountains as test object, this paper studied the variations of leaf dry mass per unit area (LMA), leaf carbon (C), nitrogen (N), and phosphorus (P) contents per unit mass and per unit area, as well as the leaf N and P resorption efficiency and use efficiency at upper and lower canopy positions during growth season (from June to October). In the growth season, and at both upper and lower canopy positions, the LMA and leaf C content per unit area had obvious monthly fluctuation, the leaf N and P contents per unit area had the similar monthly variation trend with the leaf N and P contents per unit mass, but the leaf N and P resorption efficiency per unit mass had no significant difference with the leaf N and P resorption efficiency per unit area. The leaf N resorption efficiency and use efficiency were less affected by canopy position, but the leaf P resorption efficiency and use efficiency were higher at upper canopy than at lower canopy. Under the scenario of future climate change, the higher survival and competitive capabilities of Q. mongolica would benefit the nutrient cycling in the test forest ecosystem.

Eco-physiological responses of high-latitude transplanted Aegiceras corniculatum seedlings to NaCl stress.

2011, 22(09):  2279-2284. 

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A sand culture pot experiment was conducted to study the eco-physiological responses of high-latitude transplanted mangrove Aegiceras corniculatum seedlings to varying concentration of NaCl (0, 100, 200, 300, and 400 mmol·L^-1). Under the stress of 100 mmol NaCl·L^-1, the seedling growth was slightly promoted; whereas at 300 mmol NaCl·L^-1, the plant height, stem basal diameter, fresh and dry mass, and root/shoot ratio were decreased significantly. High salt stress inhibited the leaf superoxide dismutase (SOD) and peroxidase (POD) activities, increased the leaf malondialdehyde (MDA) content, and decreased the leaf chlorophyll and carotenoids contents as well as the total soluble sugar and free amino acid contents in different organs. Under the stress of different concentration NaCl, the Na⁺contents in leaf, stem, and root increased rapidly while the K⁺ contents had a relatively decrease, resulting in a rapid decrease of K⁺/Na⁺ ratio and an imbalance between K⁺ and Na⁺ in A. corniculatum vegetative organs. When the NaCl concentration in the medium was higher than 300 mmol·L^-1, the C and N metabolism of A. corniculatum vegetative organs was maladjusted, which inhibited the normal growth of the seedlings, resulting in a significant decrease in the plant height and fresh and dry mass.

Effects of copper stress on Medicago sativa seedlings leaf antioxidative system.

2011, 22(09):  2285-2290. 

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This paper studied the effects of different concentration (0, 10, 30, 50, and 100 μmol·L^-1) CuSO₄on the leaf physiological and biochemical characteristics of Medicago sativa seedlings cultured with 1/4-strength Hoagland nutrient solution. In treatments 30, 50, and 100 μmol·L^-1 of CuSO₄, the leaf H₂O₂, OH·, and MDA contents and Fe-SOD and EST activities increased, and GSH and AsA contents increased significantly. With increasing concentration Cu, the POD, GR, and APX activities increased gradually, and the CAT and G6PDH activities decreased after an initial increase. In treatments >10 μmol·L^-1 of Cu, the capacity of leaf antioxidative system in reactive oxygen species scavenging increased to prevent the injury from copper-induced oxidative stress.

Effects of ground surface mulching in tea garden on soil water and nutrient dynamics and tea plant growth. 

2011, 22(09):  2291-2296. 

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Taking a 2-year old tea garden in Qingdao of Shandong Province as test object, this paper studied the effects of different mulching modes on the soil water and nutrient dynamics and tea plant growth. Four treatments were installed, i.e., no mulching (CK), straw mulching (T₁), plastic film mulching (T₂), and straw plus plastic film mulching (T₃). Comparing with CK, mulching could keep the soil water content at a higher level, and enhance the water use efficiency. In treatments T₁ and T₃, the tea growth water use efficiency and yield water use efficiency increased by 43%-48% and 7%-13%, respectively, compared with CK. Also in treatments T₁ and T₃,the contents of soil organic matter, available-N, nitrate-N, and ammonium-N increased significantly, with the soil fertility improved, and the leaf nitrate-N content and nitrate reductase activity increased, which promoted the tea growth and yield (12%-13% higher than CK) and made the peak period of bud growth appeared earlier. Considering the tea growth and yield, water and nutrient use efficiency, environment safety and economic benefit,  straw mulching could be an effective ground surface mulching mode for young tea garden.

Microbial carbon utilization in rhizosphere soils of secondary plants in earthquake fault zone of Xinjiang.

2011, 22(09):  2297-2302. 

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By using BIOLOG technique, this paper studied the microbial carbon utilization in the rhizosphere soils of six kinds of secondary plants in Fuyun earthquake fault zone of Xinjiang. Most of the rhizosphere soils had significantly higher nutrient contents, and all of them had a higher AWCD, as compared with the control. There was a distinct difference in the AWCD among the six rhizosphere soils. Secondary plants less affected the richness but changed the dominance and evenness of the microbial carbon sources in the rhizosphere soils. The carbon sources utilization by the microorganisms in the rhizosphere soils differed with the kinds of secondary plants, and was mainly manifested in the utilization of carbohydrates, amino acids, and carboxylic acids. The appearance of secondary plants in the earthquake fault zone made the types of carbon sources utilized by the microorganisms changed from phenols to carbohydrates and carboxylic acids. In addition, the available K content in rhizosphere soils had a negative correlation with the microbial utilization of polymers (r=-0.84) and amines (r=-0.83). It was suggested that the secondary plants in the earthquake fault zone of Xinjiang could significantly enhance the capability of soil microorganisms in carbon sources utilization, and change the types of carbon sources utilized by the microorganisms. Rosa spinosissima and Achillea millefolium played the best roles in enhancing the carbon source utilization capability of soil microorganisms and in improving soil nutrient status.

Diversity and stability of arthropod community in peach orchard under effects of ground cover vegetation.

2011, 22(09):  2303-2308. 

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A comparative study was conducted on the arthropod community in peach orchards with and without ground cover vegetation. In the orchard with ground cover vegetation, the individuals of beneficial, neutral, and phytophagous arthropods were 1.48, 1.84 and 0.64 times of those in the orchard without ground cover vegetation, respectively, but the total number of arthropods had no significant difference with that in the orchard without ground cover vegetation. The species richness, Shannon’s diversity, and Pielou’s evenness index of the arthropods in the orchard with ground cover vegetation were 83.733±4.932, 4.966±0.110, and 0.795±0.014, respectively, being significantly higher than those in the orchard without ground cover vegetation, whereas the Berger-Parker’s dominance index was 0.135±0.012, being significantly lower than that (0.184±0.018) in the orchard without ground cover vegetation. There were no significant differences in the stability indices S/N and S_d/S_p between the two orchards, but the N_n/N_p, N_d/N_p, and S_n/S_p in the orchard with ground cover vegetation were 0.883±0.123. 1714±0.683, and 0.781±0.040, respectively, being significantly higher than those in the orchard without ground cover vegetation. Pearson’s correlation analysis indicated that in the orchard with ground cover vegetation, the Shannon’s diversity index was significantly negatively correlated with N_d/N_p, S_d/S_p, and S/N but had no significant correlations with N_n/N_p and S_n/S_p, whereas in the orchard without ground cover vegetation, the diversity index was significantly positively correlated with N_n/N_pand N_d/N_p and had no significant correlations with S_d/S_p,S_n/S_p, and S/N.

Soil microbes functional diversity in sand-fixing Caragana microphylla communities in Horqin Sandy Land.

2011, 22(09):  2309-2315. 

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Aimed to understand the soil microbes functional diversity in sand-fixing Caragana microphylla communities in Horqin Sandy Land, the soil microbial carbon sources metabolism diversity in 9-, 16-, and 26-yr-old C. microphylla plantations, natural C. microphylla community, and moving sand dune was examined by the method of Biolog ECO-microplate culture. Within 264 h of culture, the average well color development (AWCD) and the capabilities of soil microbes in metabolizing carboxylic acids, carbohydrates, polymers, amino acids, amines, and aromatics were obviously higher in moving sand dune than in the plantations. The carbon source types metabolized by soil microbes increased with the increasing age of the plantations, and the carbon source metabolic pattern of the soil microbes in 26-yr-old C. microphylla plantation was similar to that in natural C. microphylla community. The functional diversity and evenness index of soil microbes decreased after the establishment of C. microphylla on moving sand dune, whereas the functional diversity of soil microbes increased with increasing age of C. microphylla plantation.

Mechanism of tomato plants enhanced disease resistance against early blight primed by arbuscular mycorrhizal fungus Glomus versiforme.

2011, 22(09):  2316-2324. 

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Arbuscular mycorrhiza (AM) can not only improve host plants nutrient absorption, but also enhance their disease resistance. Taking the tomato (Lycopersicon esculentum) seedlings pre-inoculated with arbuscular mycorrhizal fungus (AMF) Glomus versiforme as test materials, this paper studied their protective enzyme activities and defense-related genes expression, and their resistance against a fungal pathogen Alternaria solani Sorauer which causes early blight. The seedlings pre-inoculated with AMF and later inoculated with A. solani showed significantly higher activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves. The leaf SOD activity of the dually inoculated plants reached the maximum 18 h after pathogen inoculation, being 28.6%, 79.2%, and 82.8% higher than that of the plants with G. versiforme inoculation alone, pathogen inoculation alone, and non-inoculation, and the leaf POD activity reached the maximum 65 h after pathogen inoculation, being 762%, 18.3%, and 1710% higher, respectively. Real time RT-PCR analysis showed that dual inoculation with G. versiforme and A. solani strongly induced the expression of three defense-related genes. The transcript levels of pathogen-related protein (PR1),basic type β-1,3-glucanase(PR-2), and chitinase(PR-3) in leaves were 9.67-, 8.54-, and 13.4-fold higher, as compared with the non-inoculation control, respectively. Bioassay showed that the disease incidence and disease index of the seedlings pre-inoculated with G. versiforme were reduced by 36.3% and 61.4%, respectively, as compared with the non-mycorrhizal control plants. These findings indicated that mycorrhizal colonization could induce stronger and quicker defense responses of host tomato plants, and priming could be an important mechanism of the enhanced disease resistance of mycorrhizal tomato plants.

Cold-tolerance of walnut cultivars: A comprehensive evaluation.

2011, 22(09):  2325-2330. 

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In order to speed up the cold-tolerance breeding and improve the cultivation efficiency of walnut to further expand its planting area, six walnut cultivars (lines) including Luguo No.8, N13-1, Luguo No.12, N17-24, Taile, and Xiangling were taken as test materials and treated at -15 ℃, -20 ℃, -25 ℃, -30 ℃, and -35 ℃, with their tissue’s water content, membrane permeability, lipid peroxidation, protective enzyme activities, and osmotic adjustment substances determined to detect the cold resistance of the cultivars (lines). There existed greater differences in the ratio of free water to bound water in the branches of the cultivars (lines). Under low temperature treatment, the branches membrane permeability and malondialdehyde  content increased, superoxide dismutase  activity presented an ascend-descend-ascend-descend trend, catalase  activity decreased after an initial increase, and the soluble protein and proline contents increased, but the variation degrees of these parameters differed with cultivars (lines). After the recovery from low temperature, N17-24 and Luguo No.12 had a significantly higher germination rate than the other cultivars (lines). By using fuzzy mathematics method, the cold-resistance of test walnut cultivars (lines) was evaluated as N17-24＞Luguo No.12＞N13-1＞Luguo No.8＞Taile＞Xiangling.

Effects of applying nitrogen fertilizer  and fertilizer additive on rice yield and rice plant nitrogen uptake, translocation, and utilization.

2011, 22(09):  2331-2336. 

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A field experiment was conducted in the Taihu Lake region of southern Jiangsu to study the effects of applying  nitrogen (N) fertilizer and fertilizer additive on the rice yield and the rice plant N uptake, translocation, and utilization. Applying  N fertilizer had significant positive effects on the rice yield, accumulative absorbed N at all growth stages and at each growth stage, and N translocation rate after anthesis (P<0.01). However, when the N application rate exceeded 200 kg·hm^-2, its yield-increasing effect was not significant (P>0.05). The N translocation rate after anthesis and the N fertilizer use efficiency decreased with increasing N application rate. Applying fertilizer additive further improved the rice yield, accumulative absorbed N, N translocation rate after anthesis, and N fertilizer use efficiency, and this effect was more evident when the N application rate was equal to or greater than 200 kg·hm^-2. Relatively high rice yield and N use efficiency were achieved when applying 150 kg·hm^-2 of  N fertilizer without the application of fertilizer additive.

Characteristics of accumulated temperature demand and its utilization of maize under different ecological conditions in Northeast China.

2011, 22(09):  2337-2342. 

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To understand the accumulated temperature (ACT) demand of maize for its normal maturation among years and regions as well as the use efficiency of local ACT, a group of work-net field experiments was conducted at 55 sites in 28 regions of Northeast China spring maize planting area (40°07′- 48°08′ N) in 2007-2009, taking an eurychoric maize variety Zhengdan 958 as test object. The meteorological conditions in the area had large difference. In the same regions, the active accumulated temperature above 10 ℃ in whole corn growth season (ACT₁₀ for short)  demand of Zhengdan 958 for completing its whole growth and development process had little difference among different years (P＞0.1). However, in different regions, this demand differed significantly (P＜0001) in the same years, with the largest difference occurred from seedling stage to emergence stage, followed by at post-silking stage, and the least at pre-silking stage. The maturity degree of Zhengdan 958 had significant correlations with local heat conditions, and there was a linear relationship between  use efficiency and latitude. Zhengdan 958 could be safely matured in the regions with the ACT₁₀ being more than 3000 ℃, and had a risk of immaturity in the regions with the ACT₁₀ less than 3000 ℃. In conclusion, under certain meteorological conditions, the ACT demand of Zhengdan 958 for completing its growth process was relatively stable, and, due to the self physiological adjusting, the ACT₁₀ demand of Zhengdan 958 at its different growth stages showed a significant difference among different regions.

Adaptability of cucumber plug seedlings to daytime temperature.

2011, 22(09):  2343-2347. 

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Cucumber plug seedlings were cultured in a phytotron to study their responses to different daytime temperature. The daytime temperature was controlled at 30 ℃, 27 ℃, 24 ℃, 21 ℃, 18 ℃ and 15 ℃, and the night temperature was at 15 ℃, with the thickness and length of hypocotyl, length and width of the first and the second leaves, dry matter accumulation of above- and under-ground parts, leaf moisture content, and leaf chlorophyll fluorescence parameters measured. Principal component analysis and clustering analysis were made to analyze the seedling quality under different temperature treatment. There existed significant differences in the test growth indices among different treatments, with the seedling quality decreased at the daytime temperature 24 ℃ > 21 ℃ > 27 ℃ > 30 ℃ > 18 ℃ > 15 ℃. All the daytime/nighttime temperature treatments could be classified into three groups, i.e., optimum temperature (24 ℃/15℃), appropriate temperature (21 ℃/15 ℃), and inappropriate temperature, and the inappropriate temperature could be further subdivided into two groups, i.e., high-temperature inhibition (27 ℃/15 ℃, 30 ℃/15 ℃) and low-temperature inhibition (15 ℃/15 ℃, 18 ℃/15 ℃).

Effects of alternative furrow irrigation and nitrogen application rate on photosynthesis, growth, and yield of cucumber in solar greenhouse.

2011, 22(09):  2348-2354. 

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This paper studied the effects of alternative furrow irrigation and nitrogen (N) application rate (no N, optimal N, and conventional N) on the photosynthesis, growth characteristics, yield formation, and fruit quality of cucumber (Cucumis sativus) cultivar Jinyu No.5 in a solar greenhouse in winter-spring growth season and autumn-winter season. Under alternative furrow irrigation, the net photosynthetic rate of upper, middle, and lower leaves was appreciably lower and the transpiration rate decreased significantly, and the transient water use efficiency of upper and middle leaves improved, as compared with those under conventional irrigation. Stomatal factor was the limiting factor of photosynthesis under alternative furrow irrigation. The photosynthesis and transient water use efficiency of functional leaves under alternative furrow irrigation increased with increasing N application rate. Comparing with conventional irrigation, alternative furrow irrigation decreased leaf chlorophyll content and plant biomass, but increased root biomass, root/shoot ratio, and dry matter allocation in root and fruit. The economic output under alternative furrow irrigation was nearly the same as that under conventional irrigation, whereas the water use efficiency for economic yield increased significantly, suggesting the beneficial effects of alternative furrow irrigation on root development and fruit formation. With the increase of N application rate, the leaf chlorophyll content, chlorophyll a/b, specific leaf mass, plant biomass, economic yield, and fruit Vc and soluble sugar contents under alternative furrow irrigation increased, but no significant difference was observed between the treatments optimal N and conventional N. N application had little effects on the water use efficiency for economic yield. The economic yield and biomass production of the cucumber were significantly higher in winter-spring growth season than in autumn-winter growth season.

Effects of herbicide on grape leaf photosynthesis and nutrient storage.

2011, 22(09):  2355-2362. 

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Selecting three adjacent vineyards as test objects, this paper studied the effects of applying herbicide in growth season on the leaf photosynthetic apparatus and branch nutrient storage of grape Kyoho (Vitis vinifera×Vitis labrusca). In the vineyards T₁ andT₂ where herbicide was applied in 2009, the net photosynthesis rate (P_n) of grape leaves had a significant decrease, as compared with that in vineyard CK where artificial weeding was implemented. The leaves at the fourth node in vineyard T₁ and those at the sixth node in vineyard T₂ had the largest decrement of P_n (40.5% and 32.1%, respectively). Herbicide had slight effects on the leaf stomatal conductance (G_s). In T₁where herbicide application was kept on with in 2010, the P_n was still significantly lower than that in CK; while in T₂ where artificial weeding was implemented in 2010, the P_n and G_s of top- and middle node leaves were slightly higher than those in T₁, but the P_n was still lower than that in CK, showing the aftereffects of herbicide residual. The herbicide application in 2009 decreased the leaf maximum photochemical efficiency of PSⅡ(F_v/F_m) and performance index (PI) while increased the relative variable fluorescence in the J step and K step, indicating the damage of electron transportation of PSⅡ center and oxygen-evolving complex. Herbicide application decreased the pigment content of middle-node leaves in a dose-manner. Applying herbicide enhanced the leaf catalase and peroxidase activities significantly, increased the superoxide dismutase (SOD) activity of middle-node leaves, but decreased the SOD activity of top- and bottom node leaves. After treated with herbicide, the ascorbate peroxidase (APX) activity of middle- and bottom node leaves increased, but that of top-node leaves decreased. Herbicide treatment aggravated leaf lipid peroxidation, and reduced the soluble sugar, starch, free amino acids, and soluble protein storage in branches.

Distribution characteristics of soil profile  nitrous oxide concentration in paddy fields with different rice-upland crop rotation systems.

2011, 22(09):  2363-2369. 

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To investigate the dynamic distribution patterns of nitrous oxide (N₂O) in the soil profiles in paddy fields with different rice-upland crop rotation systems, a special soil gas collection device was adopted to monitor the dynamics of N₂O at the soil depths 7, 15, 30, and 50 cm in the paddy fields under both flooding and drainage conditions. Two rotation systems were installed, i.e., wheat-single rice and oilseed rape-double rice, each with or without nitrogen (N)application. Comparing with the control, N application promoted the N₂O production in the soil profiles significantly (P<0.01), and there existed significant correlations in the N₂O concentration among the four soil depths during the whole observation period (P<0.01). In the growth seasons of winter wheat and oilseed rape under drainage condition and with or without N application, the N₂O concentrations at the soil depths 30 cm and 50 cm were significantly higher than those at the soil depths 7 cm and 15 cm; whereas in the early rice growth season under flooding condition and without N application, the N₂O concentrations at the soil depth 7 cm and 15 cm were significantly higher than those at the soil depths 30 cm and 50 cm (P<0.05). No significant differences were observed in the N₂O concentrations at the test soil depths among the other rice cropping treatments. The soil N₂O concentrations in the treatments without N application peaked in the transitional period from the upland crops cropping to rice planting, while those in the treatments with N application peaked right after the second topdressing N of upland crops. Relatively high soil N₂O concentrations were observed at the transitional period from the upland crops cropping to rice planting.

Effects of applying controlled release fertilizers on N₂O emission from a lateritic red soil.

2011, 22(09):  2370-2376. 

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Static closed chamber technique and contrast method were adopted to study the effects of three coated compound fertilizers (N:P₂O₅:K₂O=19:8.6:10.5, high N; 14.4:14.4:14.4, balanced NPK; and 12.5:9.6:20.2, high K) on the N₂O emission from a lateritic red soil under the condition of no crop planting, taking uncoated compound fertilizers (N:P₂O₅:K₂O=20:9:11, high N; 15:15:15, balanced NPK; and 13:10:21, high K) as the contrasts. Different formula of fertilizer NPK induced significant difference in the N₂O emission. Under the application of uncoated compound fertilizers, the cumulative N₂O emission was in the order of balanced NPK ≥ high N > high K. Applying coated compound fertilizers decreased the N₂Oemission significantly, and the emission amount under the application of high N, balanced NPK, and high K was 34.4%, 30.5%, and 89.3% of the corresponding uncoated compound fertilizers, respectively. Comparing with the application of uncoated compound fertilizers, applying coated compound fertilizers also decreased the daily N₂O flux significantly, and delayed and shortened the N₂O peak, suggesting that coated fertilizers could reduce soil nitrogen loss and the global warming potential induced by N₂O emission.

Ecological function regionalization of Haihe River basin.

2011, 22(09):  2377-2382. 

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Aiming at the features of Haihe River basin, and by using RS and GIS technologies in combining with qualitative and quantitative analyses, a regionalization was conducted on the ecological function of the basin. The Haihe River basin could be divided into 5 ecoregions, 24 sub-ecoregions, and 114 eco-functional zones. Furthermore, 11 critical eco-functional zones were identified, according to the dominant functions (water conservation, soil conservation, wind prevention and sand fixation, and biodiversity protection) at basin scale. This regionalization made clear the regions important for the ecological security of Haihe River basin, which could guide the orderly exploitation and utilization of natural resources and the rational distribution of industries, offer scientific basis for the ecological environment protection, and maintain the ecological security of the basin.

Ecological benefits of greening and related controlling factors in urban residential areas of Hangzhou: A quantitative analysis. 

2011, 22(09):  2383-2390. 

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Based on the 1 m×1 m high resolution aerial images in 2007 and the 30 m×30 m Landsat 5 TM images in summer 2007, and with the help of GIS and remote sensing image interpretation, this paper calculated the normalized difference vegetation indices (NDVI) representing the overall ecological benefits of greening as well as the six controlling factors, i.e., multilayer structure height, area ratio of softness to hardness, greening rate, floor area ratio, greening area, and building density, in 30 typical urban residential quarters of west Hangzhou. The contributions of the controlling factors to the ecological benefits of greening as well as the quantitative relationships between the overall ecological benefits and the six controlling factors were analyzed by multiple linear regression and correspondence analysis, and some advises were given for the improvement of the ecological benefits. The contribution rate of the six factors was in the order of multilayer structure height > area ratio of softness to hardness > greening rate > floor area ratio > greening area > building density, and the contribution of multilayer structure height was far greater than that of the others whereas building density had the weakest effect on the ecological benefits. Correspondence analysis was effective in simplifying a complex data table into an intuitive two-dimensional chart, and thus, a potential powerful tool in decision-making for the improvement of ecological benefits of greening in urban residential quarters.

Contribution rates of landscape driving factors in coastal reclamation zone based on CLUE-S model validation.

2011, 22(09):  2391-2398. 

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Based on the TM images, social-economic data, and field investigation data in 1990, 2000, and 2009, and by adopting redundancy analysis (RDA) and principal component analysis (PCA), this paper analyzed the contribution rates of landscape driving forces in coastal area of Fengxian reclamation zone at Yangtze Estuary. Kappa index was used to validate the simulation effectiveness of CLUE-S model. In the study area, anthropogenic landscape driving factors had a higher contribution rate than natural landscape driving factors (57.1% vs. 42.9%). The prediction accuracy rate of CLUE-S model was above 82%, the Kappa index of the main landscape types (farm land, unutilized land, and breeding ponds) was greater than 0.75, the simulation results were acceptable, and the landscape driving forces selected could better simulate the spatial distribution patterns of the abrupt transformation of the main landscape types.

Service value assessment of orchard ecosystem: A case of  Putian City of Fujian. 

2011, 22(09):  2399-2404. 

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Based on the equivalent weight factor of China terrestrial ecosystem service value, and by using ecosystem service value assessment model, this paper evaluated the orchard ecosystem service value in Putian City. In 2002-2008, the orchard ecosystem service value in the City had an overall increasing trend, among which, the service value of gas regulation and water resource conservation had a fluctuation trend of decreased after an initial increase, and that of other functions increased rapidly in 2002-2006 and then developed mildly. The service value of regulation function was higher than that of direct use function, showing that only on the basis of preserving well the functions of ecosystem, could the orchard ecosystem be claimed and used. As most of the orchards in the City are on hills or mountains, the construction and ecological protection of the orchards are obviously disjointed, making the orchards become bare land or other land-use types, resulting in serious soil erosion and degradation, which not only destroyed the orchard ecology, but also gave negative effects on the production efficiency of agriculture. In the future construction of Putian orchards, it should implement comprehensive planning and management of mountain areas, water regions, farm lands, forest lands, and paths, reduce the orchard construction costs by taking advantage of high and new technologies in light of the local conditions and the demands of domestic and foreign markets, and promote the virtuous circle of ecosystem by comprehensive utilization of resources and regulation of biological interaction to make the structure of the orchard ecosystem approached to scientific and rational.

Insect diversity of different habitat types in Zhalong Wetland, Northeast China.

2011, 22(09):  2405-2412. 

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In order to approach the effects of different habitat types in wetland on insect diversity, an investigation was conducted on the insects in eight types of habitats in Zhalong Wetland. A total of 5822 insects were collected, belonging to 143 species, 58 families, and 11 orders, among which, Orthoptera, Dipteral and Odonata were the dominant taxa. The species diversity was the highest in grassland meadow, and the Shannon diversity index and evenness index were higher in lakeside but the lowest in wet meadow. Cluster analysis and principal component analysis showed that the similarity of the insect community in the habitats was related to the water source status and vegetation type, and the species and individual number of predatory taxa had important regulation effects on the insect community stability. Lakeside had the strongest insect community stability, while wet meadow had the weakest one, indicating that habitat water source status could affect insect survival, and further, affect the species composition and distribution pattern of insect community.

Effects of Beauveria bassiana on Myzus persicae and its two predaceous natural enemies.

2011, 22(09):  2413-2418. 

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A Beauveria bassiana strain Bb21 was isolated from naturally infected green peach aphid Myzus persicae (Hemiptera: Aphididae). The effects of the strain on M. persicae and its two predaceous natural enemies Chrysoperla carnea(Neuroptera: Chrysopidae) and　Harmonia axyridis (Coleoptera: Coccinellidae) were investigated under laboratory conditions. Bb21 had strong pathogenicity to M. persicae, with the LD₅₀ of 97 conidia·mm^-2(45-191, 95% confidence interval), but was less pathogenic to the second instar nymph of C. carnea, with the LD₅₀ of 1089 conidia·mm^-2. The LD₅₀ for C. carnea was 10.2 times higher than that for M. persicae. The pathogenicity of Bb21 to H. axyridis was very weak, with a low infection rate of 13% even at a high concentration 5×10⁸ conidia·mL^-1. The Bb21 at low conidia concentration had less effect on the developmental period and fecundity of the two predaceous natural enemies.　However, when applied at the high concentration 5×10⁸ spores·mL^-1, Bb21 shortened the larval stage of H axyridis averagely by 1.4 d and decreased the adult emergence rate and fecundity by 33% and 14%, respectively,and shortened　the larval stage of C. carnea averagely by 0.7 d and decreased the adult emergence rate and fecundity by 24% and 11%, respectively. Since the LD₅₀ for green peach aphid was much lower than that for the two predaceous natural enemies, and had very low effect on the adult emergence rate and fecundity of the two predators at the concentration recommended for field spray, Bb21 could be applied as a biocontrol agent of  M. persicae in the integrated management of pernicious organisms.

Bioactivity of the metabolites from endophytic actinomycete Fq24 against Tetranychus cinnabarinus. 

2011, 22(09):  2419-2423. 

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An endophytic actinomycete strain Fq24 was isolated from healthy tomato plants. The acaricidal substances in the metabolites from Fq24 were collected and identified by the methods of extraction, column chromatography, and gas chromatography-mass spectrometry (GC-MS), and their bioactivities against Tetranychus cinnabarinus were measured with slide-dip and leaf-residue methods. Among the extracts, petroleum ether extract had high bioactivity in contact toxicity and oviposition deterrent against T. cinnabarinus. Its lethal concentration of 50% (LC₅₀) was 52.57 mg·L^-1, and its oviposition deterrent concentration of 50% (ODC₅₀) was 43.18 mg·L^-1. The identification with GC-MS showed that the main chemical component of fraction S₁₁ was methyl hexadecanoate, whose molecular formula was C₁₇H₃₄O₂, being one of the substances with acaricidal activity in the metabolites from Fq24.The24 h corrected mortality rate of female mite at 5 mg·mL^-1 of methyl hexadecanoate was 78.3%, and the oviposition deterrent rate was 81.6%.

Spatiotemporal distribution of macrobenthic communities and its relationships with environmental factors in Sanmen Bay.

2011, 22(09):  2424-2430. 

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In November 2006 and in January, April, and August 2007, an investigation on the macrobenthic communities was conducted at 18 stations in Sanmen Bay to study the relationships between the macrobenthic communities and environmental factors. A total of 124 taxa were collected, including 44 species of Polychaeta, 34 species of Crustacea, 22 species of Mollusca, 11 species of Echinodermata, and 13 species of others. The species of Polychaeta and Mollusca accounted for 62.9% of the total, which constituted the main population of the communities. Aglaophamus dibranchis,Capitella capitata,and Sternaspis scutata were the dominant species in spring, Sternaspis scutata, Aglaophamus dibranchis, and Spionidae spp. were the dominant species in summer, S. scutata, C. capitata, A. dibranchis and Virgularia gustaviana were the dominant species in autumn, and A. dibranchis, S. scutata, C. capitata, and Spionidae spp. were the dominant species in winter. There was a significant difference in the average biomass and average density of the macrobenthic communities between different seasons. The annual average biomass was 17.36 g·m^-2, and the annual average density was 72 ind·m^-2. The diversity indices of the macrobenthic communities also differed significantly between different seasons. The seasonal average Shannon diversity index was from 1.53 to 1.89, seasonal average Margalef species richness index was from 2.25 to 2.96, and seasonal average Pielou evenness index was from 0.83 to 0.94. Canonical correspondence analysis showed that the sea water temperature, salinity, and dissolved inorganic nitrogen, and the organic matter, total nitrogen, and total phosphorus in surface sediment were the main environmental factors affecting the macrobenthic communities. Environmental variables could better explain the changes of main macrobenthic species.

Phytoplankton community structure in Shijiuyang constructed wetland of Jiaxing, Zhejiang Province of East China in winter.

2011, 22(09):  2431-2437. 

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Aimed to explore the purification effect of constructed wetland on phytoplankton community structure, an investigation was conducted on the species  composition, biomass, and community diversity of phytoplankton in the water body of Shijiuyang constructed drinking water source wetland of Jiaxing, Zhejiang Province of East China in winter, 2010. A total of 77 phytoplankton species were identified, belonging to 39 genera of 7 phyla. The main phylum was Bacillariophyta, with 33 species of 14 genera. The dominant species were Melosira varians, Cyclotella meneghiniana, Nitzschia sp., Chroococcus sp., Dactylococcopsis rhaphidioides, Scendesmus quadricauda, and Tribonema bombycium, among which, C. meneghiniana had the highest dominance (0.144). The phytoplankton density in winter was averagely 1.28×10⁶ cell·L^-1, with the minimum (6.80×10⁵cell·L^-1) in the water outlet, and the density of Cyanophyta in the water outlet was significantly lower than that in the water inlet (P<0.05), only occupying 14.9% of the latter. The Shannon index of the phytoplankton community at the sampling sites ranged from 0.94 to 1.27. According to the cluster analysis and multidimensional scaling (MDS), the phytoplankton community was classified into five phytoplankton community groups, i.e., root-channels littoral community, root-channels flow community (2 styles), highly purified area community, and headwater region community. Diverse ecological environment and water flow velocity at the sampling sites were found to be the main contributors to the formation of the five phytoplankton community groups.

Effects of acid and alkaline stress on energy metabolism of Oreochromis niloticus juveniles with different body mass.

2011, 22(09):  2438-2446. 

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A 6SymboltB@ 3 factorial laboratory experiment was conducted to study the effects of acid and alkaline stress (pH 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) on the oxygen consumption rate (OR), ammonia excretion rate (NR), and lactate dehydrogenase (LDH) and Na⁺-K⁺ adenosine triphosphatase (Na⁺-K⁺ ATPase) activities of Oreochromis niloticus juveniles with body mass 1.02, 5.13, and 10.31 g. With increasing pH, the juveniles OR and NR increased first, peaked at pH 7.0-8.0, and decreased then. The OR and NR increased with increasing body mass, and their relationships fitted power equations. The linear effects of pH and body mass and the quadratic effect of pH on the OR and NR were highly significant (P<0.01), but the pH and body mass had less synergistic effect on the OR and NR (P>0.05). Regressive equations of pH and body mass with the OR and NR were established, the R² being 0.942 and 0.936, respectively (P<0.01). Body mass had significant effects on the O:N ratio (P<0.01), whereas acid and alkaline stress could alter the energy source utilization patterns of the juveniles. High pH was not favorable to the LDH activity, but favorable to the  Na⁺-K⁺ ATPase activity. The pH had linear and quadratic effects on the LDH and Na⁺-K⁺ ATPase activities (P<0.01), body mass had no significant effect on the  Na⁺-K⁺ ATPase activity, and the pH and body mass had no synergistic effect on the two enzyme activities (P>0.05).

Accumulation and degradation of organochorine pesticides in shellfish culture environment in Xiamen sea area.

2011, 22(09):  2447-2456. 

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By using GC-ECD, the concentrations of organochlorine pesticides hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in the shellfish culture environment (sea water, sediments, and culture-shellfishes) in Xiamen sea area were analyzed, and the accumulation and degradation patterns of the HCH and DDT were preliminarily approached. In the sea area, there existed remarkable differences in the accumulation and degradation of HCH and DDT among different shellfish culture environments, being mostly associated with the habitation environment and physiological life habits of shellfish. The accumulated HCH isomers (R_x>1) were mainly β-HCH, δ-HCH, and γ-HCH, whereas the degraded HCH isomers (R_x<1)were mainly α-HCH. The ratio of α-HCH to γ-HCH was less than or equal to 1.0, suggesting that the HCH was come from industrial HCH and lindane, most of the HCH had remained in the culture environment for a longer time,and a small amount of lindane was imported.The DDT in the sea water was aerobically degraded, its main degradation product was DDE, and the ratios of (DDD+DDE) to DDTs (p,p-DDE+p,p-DDD+o,p-DDT+ p,p-DDT) was less than 0.5, whereas the DDT in sediments and shellfishes was anaerobically degraded, its main degradation product was DDD, and the ratios of (DDD+DDE) to DDTs was greater than 0.5, suggesting that there was a small amount of DDT newly imported in the sea water,and most DDT in sediments and shellfishes were already degraded and transformed into DDD and DDE. There were definite differences in the degradation rates of HCH isomers in the culture environment, suggesting the conformational change of HCH in its transformation processes in the shellfish culture ecosystem.

Interactions between invasive plants and arbuscular mycorrhizal fungi: A review.

2011, 22(09):  2457-2463. 

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The invasion of invasive plants changes the biological community structure in their invaded lands, leading to the biodiversity loss.As an important component of soil microorganisms in terrestrial ecosystem, arbuscular mycorrhizal (AM) fungi can affect the growth performance of invasive plants. This kind of specific relations between AM fungi and invasive plants also implies that AM fungi can affect plant invasion. On the other hand, the invasion of invasive plants can affect the community structure and function of AM fungi. This paper summarized the species and harms of invasive plants in China, and discussed the relationships between AM fungi and invasive plants invasion, including the roles of AM fungi in the processes of invasive plants invasion, the effects of the invasion on AM fungi, and the interactive mechanisms between the invasion and AM fungi.

Seasonal changes of Indocalamus leaf active ingredients contents.

2011, 22(09):  2471-2476. 

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In this paper, the leaves of Indocalamus herklotsii, Indocalamus decorus, and Indocalamus latifolius were collected from Nanjing in different seasons to study the seasonal changes of the total flavonoids, tea polyphenols, and soluble sugar contents in the leaves. There existed significant differences in the test active ingredients contents among the leaves of the three Indocalamus species. The leaf total flavonoids content of the three Indocalamus species in different seasons ranged in 1.7%-2.7%, being the highest for I. herklotsii and I. decorus in spring and for I. latifolius in winter. The leaf tea polyphenols content varied from 5.5% to 7.6%; and the leaf soluble sugar content was 1.0%-8.5%, with the maximum in spring. Within the three months after leaf unfolding, the active ingredients contents in I. herklotsii and I. decorus leaves increased with leaf age. The optimal period for harvesting Indocalamus leaves was from December to next March. Among the three Indocalamus species, I. latifolius had the highest contents of the three active ingredients in leaves, suggesting that I. latifolius had greater potential value in the utilization of its leaf active ingredients than the other two species.

Effects of tree age and basal area on boreal forest tree mortality in Canada.

2011, 22(09):  2477-2481. 

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Taking the poplar (Populus spp.), jack pine (Pinus banksiana),and black spruce (Picea mariana) in northern Canada as test objects,a repeated investigation was conducted on the living and dead trees at 134 fixed sampling plots, and linear regression models were applied to study the effects of tree age, basal area, and stand type on the mortality of the three tree species. Generally, the tree mortality increased with increasing tree age and basal area. Poplar had a higher mortality in jack pine stand but a lower mortality in black spruce stand. In black spruce stand, tree age was the major factor affecting the mortality of jack pine, while in poplar stand, tree basal area was the important factor. In the three stands, tree age had significant effects on the mortality of black spruce. Species composition had significant effects on the mortality of the tree species, and the interactions between tree age, basal area, and stand type all had significant effects on the mortality of each tree species. The mortality of the same tree species in different stands differed significantly.

Effects of seed dressing with imidacloprid on the seedlings growth and protective enzyme activities of high-yielding summer maize.

2011, 22(09):  2482-2486. 

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A field plot experiment was conducted to study the effects of seed dressing with imidacloprid at the pesticide / seed mass ratios of 6:10000，9:10000, and 12:10000 on the seedlings growth and protective enzyme activities of high-yielding summer maize. Seed dressing with an imidacloprid / seed mass ratio of 6:10000 increased the seedlings height, primary root length, secondary root number, aboveground fresh mass, and underground fresh mass by 2.81 cm, 2.31 cm, 1.71, 0.30 g, and 8.28 g, respectively, as compared to the control, and had better effect than the treatments 9:10000 and 12:10000. Comparing with the control, treatment 6:10000 increased the leaf- and root soluble protein content by 12.6% and 27.9% and catalase (CAT) activity by 2.5% and 11.5%, decreased malondialdehyde (MDA) content by 26.3% and 60.9%, improved superoxide dismutase (SOD) activity by 19.7% and 5.6%, enhanced glutathione-S-transferase (GSTs) activity by 11.5% and 13.2%, respectively, and increased the root peroxidase (POD) activity by 31.8%. Seed dressing with imidacloprid at the pesticide / seed mass ratio of 6:10000 could markedly improve maize seedlings protective enzyme activities, but had no promotion effect on leaf peroxidase (POD) activity.