微生物群落在团聚体中的分布及耕作的影响

对水稻土微生物群落在不同粒级土壤团聚体中的分布以及耕作的影响,结果表明:细菌和真菌主要分布在粒级＜0.053 mm的粉砂与粘粒组分中,而在各粒级团聚体中的分布无显著差异.放线菌主要分布在粒级为0.053～0.2 mm的土壤微小团聚体中,在其它各粒级团聚体中的分布无显著差异.研究认为水稻土微生物群落在土壤团聚体中的数量分布受土壤团聚体结构的影响.细菌、真菌、放线菌都主要分布于小粒级的土壤组分中.垄作免耕稻田显著提高了耕层土壤微生物的数量,但对微生物的分布模式没有影响.

Abstract：

The present paper reports the distribution patterns of microbial community in soil water-stable aggregates of different sizes and the effects of tillage methods on them in a paddy soil. The results showed that the pattern of microbes in arable layer was: bacteria ＞ fungi ＞ actinomyce, that bacteria and fungi were mainly distributed in sand and silt particles of ＜0. 053 mm with no marked difference among aggregates of different sizes and that actinomyces were mainly distributed in 0. 053～0.2 mm soil aggregates. It is concluded that the distribution pattern of microbial community within soil aggregates was restricted by the structure of soil aggregates. Bacteria, fungi and actinomyces were mainly distributed in microaggregates. No-tillage ridge culture remarkably increased the number of soil microbes in the arable layer but had no significant effect on the distribution patterns of soil microbes.     

重庆石漠化区主要乔木群落土壤水文功能研究——以重庆市南川示范区为例

通过对重庆石漠化区2种植物群落凋落物层和土壤层的持水性能进行研究,结果表明:马尾松群落的蓄积量高于樟树群落,蓄积量高达48.3 t/hm2,不同分解层次的蓄积量,因植物群落类型不同而有别,测定结果显示针叶林的凋落物的蓄积量、鲜质量、干质量明显高于阔叶林;在两种群落中同种凋落物的不同分解层次的最大持水量、持水率,均是半分解层高于未分解层,马尾松群落持水总量高于樟树群落,达71.5 t/hm2,相应的持水深度也是马尾松群落高于樟树群落;马尾松群落凋落物的吸水量明显高于樟树群落,且每一种凋落物的半分解层的吸水量均大于未分解层,在持水过程中,两种凋落物呈现相同的变化趋势,在前4 h内吸水速率降低幅度大,4 h后吸水速度减缓,20 h后趋向于零.凋落物吸水量和浸水时间之间存在对数关系(y=aln(x)+b),凋落物吸水速率与浸水时间的关系按照反函数方程变化(y=a+bx-1);马尾松群落的总拦蓄量(98.18 t/hm2)大于樟树群落的总拦蓄量(59.26 t/hm2);马尾松群落可截留9.818 mm的林内降雨,樟树群落可以截留5.925 mm的林内降雨.且不同分解层次上也表现为半分解层的有效拦蓄量大于未分解层.表层土壤的持水性能也和凋落物层的持水性能呈现相同的规律,也表现为马尾松林高于樟树林.

Abstract：

The water-holding capacities in 2 main forest types (Pinus tabulaeformis Lamb and Cinnamomum (L.)Presel) in mountainous eco-system in Karst area of Chongqing were studied. The results showed that the litter storage of P. tabulaeformis (48.3 t/ha) was higher than that of Cinnamomum. Different vegetation types and different decomposition levels resulted in different storages. The litter storage, the wet litter standing crop and the dry litter standing crop of conifers were higher than those of broadleaf forests. The maximum water-holding percentage and water holding capacity of the semi-decomposed layer was higher than those of the non-decomposed layer of the same vegetation type, and the total water holding capacity and the water holding depth of P. tabulaeformis was much higher than that of Cinnamomum. In the water holding process, the litter of the two vegetation types showed a similar trend. Water absorption rate dropped sharply in the first 4 hours, and slightly thereafter and approached zero after 20 hours. The total water holding capacity increased logarithmically with increasing immersion time in water (y = aln(x)+b),and water absorption rate in all plantations decreased with increasing immersion time according to the equation y= a+bx-1. The total interception amount of P. tabulaeformis and Cinnamomum was 98.18 t/ha and 59.26 t/ha, respectively; and their total interception depth was 9. 818 mm and 5. 925 mm. The modified interception amount of the semi-decomposed layer was higher than that of the non-decomposed layer.Like the litter layer, the topsoil showed a similar pattern of the water-holding properties. i.e. the waterholding capacity of the soil of P. tabulaeformis forests was better than that of Cinnamomum forests.     

Effect of Nitric Oxide on Alleviating Cadmium Toxicity in Rice (Oryza sativa L.)

Nitric oxide （NO） is a gaseous signaling molecule in plants that plays a key role in mediating a wide range of physiological processes and responses to biotic and abiotic stresses. The present study was conducted to investigate the effects of the exogenous application of sodium nitroprusside （SNP）, an NO donor, on cadmium （Cd）-induced oxidative stress and Cd uptake in rice plants. Rice plants were exposed to Cd stress (0.2 mmol L^-1 CdCl₂) and different concentrations of SNP (0.05, 0.1, 0.2, and 0.4 mmol L^-1). A SNP concentration of 0.1 mmol L^-1 （SNP10） significantly reduced the Cd-induced decrease in shoot and root dry weights and leaf chlorophyll concentrations. The addition of NO also reduced the malondialdehyde （MDA）, hydrogen peroxide （H₂O₂） and ascorbic acid （ASA） concentrations. However, the reduction in glutathione （GSH） concentration was inhibited by NO treatment. Moreover, NO prevented the Cd-induced increase in antioxidative enzyme activity. The amount of Cd accumulation in rice plants was also influenced by the addition of NO. The NO supplied by the SNP enhanced the Cd tolerance of the rice by increasing the Cd uptake by the roots and decreasing the Cd accumulation by the shoots. However, the application of potassium ferrocyanide （Cd+Fe） or sodium nitrate and nitrite （Cd+N） （without NO release）, did not exhibit the effects of the SNP. Furthermore, the effects of the SNP were reversed by the addition of hemoglobin （an NO scavenger）. Our results suggested that exogenous NO was involved in the resistance of rice to Cd-toxicity.     

环境因子对巢湖沉积物中NH4+释放的影响（英文）

[Objective] The aim of the research was to reveal the influence mechanism of sediment-water exchange of nutrients in Chaohu Lake. [Method] The effects of environmental factors （overlying water, temperature, pH and dissolved oxygen concentration） on NH₄⁺ release in sediment from Chaohu Lake were studied under controlled laboratory conditions. [Results] With the rising of temperature and the decrease of NH₄⁺ concentration in overlying water, NH₄⁺ released from sediment increased significantly. pH had a great effect on NH₄⁺ release with a complicated mechanism. The largest release amount of NH₄⁺ under anaerobic condition was about 6 times as much as that under aerobic condition. [Conclusion] This research would provide theoretical support for environmental management of Chaohu Lake in the project of leading water from the Yangtze River to Chaohu Lake.     

Photosynthetic Responses of A New Grapevine Variety ‘Xinyu’ in Turpan

Turpan is one of the major high-quality grape production bases in the world for years because its climate is so special (hot, dry, and windy). The grape market needs the varieties with high yield, quality, and environmental adaptability. ‘Xinyu’ is a new variety bred by crossing selection of E42-6 (a self-pollinated inbred of Vitis vinifera cv. ‘Red Globe’) as female and Vitis vinifera cv. ‘Rizamat’ as male parents and registered in the Crop Varieties Registered Commission of Xinjiang Uygur Autonomous Region in 2005. In this study, we determined the impacts of environmental factors on its photosynthesis. The results showed the climate in Turpan was characterized by long-time intensive sunshine, high temperature and relatively low humidity. The peak value of photosynthetic available radiation (PARi) was 1 454 μmol·m^-2·s^-1, and the minimum and average values were 111 μmol·m^-2·s^-1and 938.889 6 μmol·m^-2·s^-1, respectively. Air temperature and sunlight intensity reached the highest values during 1 p.m. to 4 p.m. Net photosynthetic rate (Pn) of Xinyu increased stably before 11 a.m. and there was a midday depression during 11 a.m. to 2 p.m. The minimum value of Pn appeared at noon (2.77 μmol·m^-2·s^-1). It was concluded that as a new grape cultivar, “Xinyu” could withstand extreme climate conditions in Turpan.     

新疆地震断裂带泉水微生物群落功能多样性

[目的]通过对地震断裂带这一特殊地质构造所形成的泉水理化指标及泉水中微生物群落代谢功能多样性的研究,考察泉水理化条件动态变化对微生物群落结构的影响.[方法]对乌鲁木齐10号泉泉水样品定期采样,使用BIOLOG ECO微孔板培养,分析泉水微生物群落功能多样性.[结果]样品的平均吸光度曲线呈现差异性;硫化氢含量显著影响该泉水微生物群落结构,其他理化指标作用不显著.[结论]该泉水微生物群落结构呈现动态变化过程并且该环境样品中的微生物对碳源利用具有偏嗜性.     

Analysis of Residues Formed during the Liquefaction Process of Wheat Straw

Wheat straw(WS) was liquefied to analyze the reaction process of WS under the acid-catalyzed conditions. WS was liquefied almost completely in the presence of ethylene carbonate/ethylene glycol(EC/EG) blend solvents within 40min at 150 ℃. The residues with different liquefaction time were investigated by SEM, FTIR, and XRD. The residues exhibited loose structure and rough surface due to the presence of stacked irregular platelets. The FTIR results demonstrated that lignin was more easily liquefied in the presence of EC/EG blend solvents than cellulose because the bands of cellulose were stronger and the bands of lignin were much weaker during the liquefaction process of WS. Moreover, the XRD result of all residues declared that WS was gradually liquefied, dissolved and decomposed to small fragments of lower molecular weight, and condensed in part in the later stage of liquefaction.     

Effects of Pesticide Applications on the Biochemical Properties of Transgenic cry 2A Rice and the Life History Parameters of Nilaparvata lugens Stl (Homptera: Delphacidae)

Effects of transgenic Bt rice on non-target pests following pesticide applications plays an important role in evaluating the ecological safety of transgenic rice. Changes of the life history parameters of laboratory population of Nilaparvata lugens feeding on transgenic Bt rice T2A-1 and its parental line cv. MH63 as the control, and the contents of oxalic acid and soluble sugar following three pesticides （triazophos, jinggangmycin and chlorantraniliprole） treatments were investigated in this paper. Results showed that the population parameters of N. lugens and the physiological and biochemical parameters of rice did not differ significantly between T2A-1 and MH63 without pesticide application. But, the emergence rate （ER）, the nymphal number of next generation （NN）, and the index of population trend （IP） on T2A-1 treated with 10 mg L^-1 of triazophos were significantly higher than those on MH63, respectively, while the hatchability （HB） on T2A-1 treated with the three pesticides were obviously lower than those on MH 63. Furthermore, the content of oxalic acid in MH63 treated with 20 mg L^-1 triazophos and, 40 and 80 mg L^-1 chlorantraniliprole was significantly higher than that in T2A-1, while the content of soluble sugar in T2A-1 treated with 400 mg L^-1 jinggangmycin was significantly higher than that in MH63. The results above indicated that triazophos in a low dose could cause a more favor of T2A-1 to population growth of N. lugens compared with MH 63.     

Regulation of Foliar Application DCPTA on Growth and Development of Maize Seedling Leaves in Heilongjiang Province

DCPTA （2-diethylaminoethyl-3, 4-dichlorophenylether） is a new plant regulator which can be used to regulate growth and development for crops. Experiments on maize seedlings were conducted in the growth chamber to study the effects of foliar applied DCPTA. The plant pots were placed in a completely randomized design with three replicates. The maize seedlings were treated with 0 mg·L-1 （control）, 20 mg·L-1 and 40 mg·L-1 DCPTA solution. The effects of DCPTA on the photosynthetic characteristics （photosynthesis, stomata conductance, intercellular CO2, and transpiration rate）, related physiological characteristics （contents of soluble sugar and starch）, chlorophyll fluorescence parameters （Fo, Fro, Fv/Fm, Fv/Fo, qP, and qN） and the weight of dry matter in maize seedling were studied. The results showed that DCPTA enhanced photosynthesis of maize seedling. In general, photosynthetic rate in leaves was significantly promoted through spraying DCPTA solution, and 40 rag＂ L~ DCPTA was found to be the best concentration for maize. The relationship between stomata conductance and transpiration rate in maize leaves could be described as linear. With regard to the chlorophyll fluorescence parameters, our fmdings showed that 40 mg·L-1 DCPTA in maize seedling caused an increase in Fm, Fv/Fm, Fm/Fo, qP and a decrease in Fo and qN at some time points checked. It is suggested that DCPTA increased photosynthetic rate by raising both the content of chlorophyll and activities of PSII and the contents of sugar and starch. Compared with the control, the treated maize seedling caused an increase in plant height, root length, shoot dry mass, root dry mass, or the total （root plus shoot） dry mass.     

Study on Biological Activity of New Compound SYP-260

SYP-260 is one of the novel pyrimidine structure chemicals. The biological activity of new compound SYP-260 was tested in this paper using different bioassay methods in the laboratory. Experimental results indicated that the values of median lethal concentration(LC₅₀, 72 h) of new compound SYP-260 against broad bean aphid, green peach aphid and cotton aphid were 0.1708, 0.2455 and 0.2632 mg · L^-1, respectively. The LC₅₀ of new compound SYP-260 was 0.8892 mg · L