猪增生性肠病（Porcine proliferative enteropathy, PPE）是由胞内劳森菌(Lawsonia intracellularis，L. intracellularis) 感染引起、在世界各地猪场中普遍存在的一种重要肠道疾病，以6~20周龄生长育肥猪急性出血性下痢、间歇性下痢、食欲下降和生长发育缓慢等临床症状为主要特征，给养猪业带来严重经济损失。准确的检测临床样品中胞内劳森菌方法对于预防和控制PPE尤其重要。研究表明，单克隆抗体在胞内劳森菌的病原学检测中发挥重要作用，热休克蛋白60 (Heat shock protein 60, Hsp60) 广泛存在于多种细菌中，是一种具有免疫保护作用的抗原。因此，本研究拟制备抗胞内劳森菌 Hsp60的单克隆抗体，并以其为一抗，用于感染细胞及感染组织中胞内劳森菌的检测。鉴于此，我们首先表达并纯化了Hsp60蛋白，并以纯化后的Hsp60蛋白为免疫原免疫BALB/c小鼠，采用杂交瘤细胞技术制备单克隆抗体。随后，通过间接ELISA和Western blotting检测单克隆抗体的特异性。最后，以本研究制备的单克隆抗体为一抗，分别采用免疫荧光和免疫组化法对体外单层感染细胞以及体内感染组织中胞内劳森菌进行检测。最终，我们成功筛选、鉴定出3株能够稳定分泌抗Hsp60蛋白单克隆抗体的阳性杂交瘤细胞株，分别命名为3E5、4E2和9G6。以BALB/c小鼠制备相应腹水单抗，间接ELISA效价分别为1:1024000、1:2048000和1:2048000。单克隆抗体特异性检测结果显示，3E5、4E2和9G6只能与胞内劳森菌反应，而与猪霍乱沙门氏菌、鼠伤寒沙门氏菌、大肠杆菌、猪痢短螺旋体等猪肠道中常见病原菌均无交叉反应，说明本研究制备的单克隆抗体具有良好的特异性。进一步研究发现，以上3种单克隆抗体均可与体外单层感染细胞及PPE感染猪回肠组织中的胞内劳森菌发生特异性结合。上述单克隆抗体为胞内劳森菌临床菌株的成功分离及免疫诊断方法的开发奠定了基础。

玉米雄穗检测是玉米种植和育种农艺管理中必不可少的技术，可应用于产量估算、生长监测、智能采摘、病害检测等方面。然而，田间的玉米雄穗普遍存在遮挡现象，不同生长阶段的雄穗大小和形态颜色也不尽相同。针对这些问题，本文提出了SEYOLOX-tiny模型，可以更精准、更鲁棒地识别田间的玉米雄穗。通过无人机构建了丰富的玉米雄穗图像数据集，在保证图像质量和图像采集效率的同时兼顾不同时期的玉米雄穗的图像多样性。另外，YOLOX嵌入注意力机制，在关键特征的提取时，能有效抑制不利因素（遮挡、重叠）的噪声，有助于应对农田多变复杂的环境。实验结果显示，改进的识别算法SEYOLOX-tiny平均检测精度达到95.0%；相较于原始模型的mAP_@0.5、mAP_@0.5-0.95、mAP_{@0.5-0.95（面积=小）}和mAP_{@0.5-0.95（面积=中）}提升1.5、1.8、5.3和1.7个百分点。因此，本文提出的方法可以满足玉米穗检测视觉系统中所需要的精度和鲁棒性。

小伞山羊草二倍体 (Ae. umbellulata, 2n=2x=14, UU) 是对普通小麦遗传改良具有潜在利用价值的小麦近缘植物。本研究报道了46份小伞山羊草的条锈病抗性、抽穗期、微量元素铁、锌含量以及“面筋蛋白”含量的调查结果。在四个环境下，42份小伞山羊草表现抗小麦条锈病，4份感条锈病。小伞山羊草的平均抽穗期 (180.9天) 显著晚于3个普通小麦对照 (137.0天)，但1份材料PI226500除外，为138.9天。小伞山羊草材料间的铁、锌含量有广泛的变异，变幅分别为69.74–348.09 mg/Kg和49.83–101.65 mg/Kg。PI 542362, PI 542363和PI 5543993份这3份材料的铁、锌含量高于其他小伞山羊草，分别为230.96–348.09 mg/Kg和92.46–101.65 mg/Kg。小伞山羊草的铁含量与顶芒山羊草 (Ae. comosa, 2n = 2x =14, MM) 和尾状山羊草 (Ae. markgrafii, 2n = 2x =14, CC) 的相当，但高于节节麦 (Ae. tauschii, 2n = 2x =14, DD) 和普通小麦对照。小伞山羊草的锌含量高于节节麦、顶芒山羊草和普通小麦对照，但低于尾状山羊草。用高效液相色谱分析了小伞山羊草以及作为对照的其他山羊草二倍体的面筋蛋白含量。与其他物种相比较，小伞山羊草具有独特的洗脱峰，如41-42分钟的低分子量谷蛋白以及大约57分钟时的γ-醇溶蛋白。在所研究的物种中，小伞山羊草的γ-醇溶蛋白含量是最高的 (小伞山羊草vs. 其他物种，平均含量: 72.11%% vs. 49.37%，变异幅度 55.33–86.99% vs. 29.60–67.91%)。这些研究结果表明，小山羊草在这些性状上有很大遗传变异，是可供用于普通小麦相关性状遗传改良利用的潜在基因库。

【目的】山羊关节炎-脑炎病毒（Caprine arthritis-encephalitis virus，CAEV）属于反转录病毒科慢病毒属成员，与梅迪-维斯纳病毒（Maedi visna virus）合称为小反刍动物慢病毒（Small ruminant lentiviruses）。该病毒可感染山羊和绵羊，以奶山羊最为易感。在过去四十年间，CAEV在我国传播扩散，并存在不同程度的感染，但有关该病毒基因组特征和可能的来源研究仍然较少，获取在中国流行的CAEV毒株的基因组数据对于开发诊断方法和根除相关疾病具有重要意义。【方法】本研究使用分段扩增和测序的方法获得了1989–1994年间从我国甘肃、贵州、陕西、山东和四川等地感染奶山羊中分离的5株CAEV病毒基因组，通过基因型分析、全基因组比对、遗传进化和种群结构分析来阐释该病毒基因组特征。【结果】我国CAEV与国外毒株基因组相似度为58%–93%，属于B型小反刍动物慢病毒，可进一步归为B1基因型。遗传进化分析结果显示本研究测定的5株病毒与其它两株中国毒株聚集成簇，亲缘关系最近，同源性为98.3%–99.3%；其次是与美国毒株Clements（GenBank登录号NC_001463.1），相似性为91.8%–92.3%；种群结构分析表明我国已测定的7株病毒拥有与其它已知毒株不同的祖先成分。【结论】跨度5年从我国不同省份分离的CAEV毒株具有高度同源性，分离株可能起源于非已知毒株的其它来源。【创新点】本研究完成了我国最早分离的5株CAEV病毒的基因组测序和基因特征分析，确认我国分离毒株高度同源，可能起源于特定的同一祖先，该结果为研制适用于我国CAEV检测的试剂和CAEV流行病学调查与防控奠定了基础。

本研究旨在明确双丙环虫酯对棉蚜的急性毒性和双丙环虫酯亚致死浓度处理对棉蚜生物学特性的影响。结果表明，双丙环虫酯对棉蚜成虫高毒，其72 h的LC₅₀值为1.062 mg L^-1。双丙环虫酯亚致死浓度（LC₁₀）处理能够显著降低了F₀代和F₁代雌成虫的寿命、产蚜量及产蚜天数。同时，LC₁₀浓度处理后，棉蚜F₁代的成虫前期存活率也下降了30%。此外，与对照相比，双丙环虫酯处理后F₁代若虫发育历期、成虫前期、成虫产蚜前期、总产蚜前期均显著延长。双丙环虫酯亚致死浓度处理显著降低了F₁代的净繁殖率（R₀）、内禀增长率（r）和周限增长率（λ）。这些结果表明，双丙环虫酯亚致死浓度能够显著抑制棉蚜的种群增长。本研究结果将有助于科学评估双丙环虫酯对棉蚜的影响。

在至少3个环境下 (除Std7为2个环境外)，对7份只表达Glu-D1等位变异的人工合成小麦(2n=6x=42，AABBDD, 本研究简称为SHWSD) 及弱筋小麦对照川农16(CN16)的面团强度和面筋蛋白含量[包括高分子量谷蛋白(HMW-GS), 低分子量谷蛋白, (LMW-GS)和醇溶蛋白]及其比例等主要品质参数进行了测定与比较。在不同环境下，SHWSD的Zeleny沉降值(ZSV)、面团形成时间(DDT)、稳定时间(DST)和粉质质量指数(FQN)基本表现一致，分别为8.00-17.67 ml、0.57-1.50 min、0.73-1.80 min和9.50-27.00。SHWSD的ZSV、DDT、DST和FQN等品质参数均小于对照CN16，说明SHWSD的面团强度比对照CN16更弱。虽然SHWSD的面筋指数低于CN16，但在所有环境中，其干、湿面筋含量均-20.31%)均高于CN16。与对照CN16比较，SHWSD在高分子量谷蛋白基因表达减少的情况下，高分子量谷蛋白含量急剧下降，但LMW-GS、醇溶蛋白和总谷蛋白含量均同时增加。此外，SHWSD具有比对照CN16更高的LMW-GS/谷蛋白和醇溶蛋白/谷蛋白比例，更低的HMW-GS/谷蛋白比例。这些结果为SHWSD在弱筋小麦育种中的应用提供了必要的信息。

该研究报道了一个新的雌性特异表达基因UBE2I，鉴定了其在鸡两性组织器官中的表达模式，并通过体内实验（干扰和过表达）研究了UBE2I在鸡胚性腺发育中的生物学功能。研究发现，UBE2I在鸡早期胚胎性腺中的PGCs（原始生殖细胞）中高表达，并在新生鸡卵巢组织中表现出高表达。与此同时，研究团队结合慢病毒和鸡胚血管注射技术建立了在鸡胚体内长期稳定干扰或过表达UBE2I表达的有效方法，并发现在UBE2I过表达的情况下，雌性的性别相关基因（FOXL2，CYP19A1和HINTW）被上调，而雄性的性别相关基因（SOX9，DMRT1和WT1）在干扰UBE2I后被下调，其对应的鸡胚性腺的组织也出现了对应的结构变化。与此同时，UBE2I表达的变化与雌二醇及其受体（AR和ESR）的水平有关，这些结果表明UBE2I是启动雌性鸡胚卵巢发育的关键因素。该研究结果有力的证明了UBE2I在鸡胚胎性别发育和分化过程中发挥了关键的作用。这是第一次报道UBE2I基因在鸡胚性别分化过程中发挥的功能，而UBE2I作为泛素化修饰过程中的重要调控因子，为进一步研究家禽性别决定的分子机理提供了新的思路。

 

Machine harvesting increases the foreign matter content of seed cotton.  Excessive cleaning causes fiber damage and economic loss.  Most trading companies in the Xinjiang Uygur Autonomous Region, China have indicated reluctance to use machine-harvested cotton.  The first objective was to determine how the fiber quality was affected by the ginning and lint cleaning and how the fiber damage during levels of lint cleaning changed. The second objective was to determine the optimum number of lint cleaners for machine-harvested cotton based on fiber damage.  Cotton samples were collected from 13 fields and processed in seven ginneries between 2013 and 2015.  The results indicated that ginning and lint cleaning didn’t have significant effect on fiber strength and significantly affected both fiber length and short fiber index.  Fiber length was reduced by more than 1.00 mm from six of 13 fields after lint cleaning, then the damage rate on short fiber index from 11 of 13 fields was more than 20%.  The third lint cleaning caused great fiber damage, reducing fiber length by 0.35 mm and increasing short fiber index by 0.65%.  So, the lint should be cleaned by one lint cleaner in the Xinjiang, however, the stage of lint cleaning was sometimes omitted when the foreign matter content of lint was little.

The wild hawthorn species, Crataegus songorica K. Koch., is an important wild germplasm resource in Xinjiang, China that has been endangered in recent years.  The genetic diversity of C. songorica K. Koch. germplasm in five populations from Daxigou, Xinjiang, China were evaluated based on phenotypic traits and ISSR molecular markers to provide basic information on resource protection, rational utilization and genetic improvement.  The F-value for the phenotypic differentiation coefficient of the 33 traits measured ranged from 0.266 to 15.128, and mean value was 13.85%.  The variation among populations was found to be lower than that within population.  A total of 303 loci were detected within the five populations by 12 primers.  Within 298 polymorphic loci, the polymorphism was 98.35%, showing a high genetic diversity in C. songorica K. Koch.  The gene diversity within population, total population genetic diversity, genetic differentiation coefficient and gene flow were 0.2779, 0.3235, 0.1408, and 3.0511, respectively.  Our results showed that C. songorica K. Koch. from Xinjiang has a high level of genetic diversity at both the phenotypic and molecular levels.  Significant genetic differentiation existed within population and the differentiation trend showed a regional association.  And in this study, in situ and ex situ conservation approaches were raised for wild hawthorn protection utilization.

Anthropogenic activities profoundly influence carbon sequestration in the Eurasian Steppe.  In particular, grazing has been identified as having a major effect on carbon sequestration.  However, the extent to which grazing affects regional patterns or carbon sequestration is unknown.  In this study, we evaluated the impact of regional grazing on grassland carbon sequestration using the Boreal Ecosystem Productivity Simulator (BEPS) and the Shiyomi grazing model.  Model performances were validated against the results from field measurements and eddy covariance (EC) sites.  Model outputs showed that in 2008, the regional net primary productivity (NPP) was 79.5 g C m^–2, and the net ecosystem productivity (NEP) was –6.5 g C m^–2, characterizing the region as a weak carbon source.  The Mongol Steppe (MS) was identified as a carbon sink, whereas the Kazakh Steppe (KS) was either carbon neutral or a weak carbon source.  The spatial patterns of grazing density are divergent between the MS and the KS.  In the MS, livestock was mainly distributed in China with relatively good management, while in the KS livestock was mainly concentrated in the southern countries (especially Uzbekistan and Turkmenistan) with harsh environments and poor management.  The consumption percentages of NPP in Turkmenistan, Tajikistan and Uzbekistan were 5.3, 3.3 and 1.2%, respectively, whereas the percentages in other countries were lower than 1%.  Correspondingly, grazing consumption contributed to the carbon sources of Turkmenistan, Tajikistan and Uzbekistan by 11.6, 6.3 and 4.3%, respectively, while it weakened the carbon sink in Inner Mongolia, China and Mongolia by 1.6 and 0.5%.  This regional pattern should be affected by different sub-regional characteristics, e.g., the continuous degradation of grassland in the southern part of the KS and the restoration of grassland in Inner Mongolia, China.

Both the additive and multiplicative models of crop yield and water supply are polynomial equations, and the number of parameters increases linearly when the growing period is specified.  However, interactions among multiple parameters occasionally lead to unreasonable estimations of certain parameters, which were water sensitivity coefficients but with negative value.  Additionally, evapotranspiration must be measured as a model input.  To facilitate the application of these models and overcome the aforementioned shortcomings, a simple model with only three parameters was derived in this paper based on certain general quantitative relations of crop yield (Y) and water supply (W).  The new model, Y/Y_m–W^k/(W^k+w_h^k), fits an S or a saturated curve of crop yield with the cumulative amount of water.  Three parameters are related to biological factors: the yield potential (Y_m), the water requirement to achieve half of the yield potential (half-yield water requirement, w_h), and the water sensitivity coefficient (k).  The model was validated with data from 24 maize lines obtained in the present study and 17 maize hybrids published by other authors.  The results showed that the model was well fit to the data, and the normal root of the mean square error (NRMSE) values were 2.8 to 17.8% (average 7.2%) for the 24 maize lines and 2.7 to 12.7% (average 7.4%) for the 17 maize varieties.  According to the present model, the maize water-sensitive stages in descending order were pollen shedding and silking, tasselling, jointing, initial grain ?lling, germination, middle grain ?lling, late grain ?lling, and end of grain ?lling.  This sequence was consistent with actual observations in the maize field.  The present model may be easily used to analyse the water use efficiency and drought tolerance of maize at specific stages.

Fruit size is one of the most important agronomic characters, which is mainly determined by cell number and cell size. However, our current knowledge about pear is largely unknown. Through counting of pear mesocarp cells at different stages, we found that the cell number, rather than the cell size, is responsible for the differences between small- and large-fruited cultivars. Fruit weight-2.2 (fw2.2) is an important quantitative trait locus (QTL) affecting fruit weight in tomato and functions as a negative regulator in carpel cell division. To get more insights into this QTL in pear fruit development, we isolated two putative homologous fw2.2 genes, which were designated as fw2.2-like (PbFWL) genes. PbFWLs encode Cys-rich proteins with the CCXXXXCPC motif and belong to the PLAC8 superfamily. In addition, results from the subcellular localization indicated that PbFWLs were localized in the plasma membrane. The expression profile of the PbFWL genes by qRT-PCR showed they expressed higher in small-sized fruit cultivar than that in large-sized fruit cultivar during the cell division period. In summary, our data suggest that these two PbFWLs might be negatively related to the cell division in pear fruit.

In the process to the marketing of cultivars, identification of superior test locations within multi-environment variety trial schemes is of critical relevance. It is relevant to breeding organizations as well as to governmental organizations in charge of cultivar registration. Where competition among breeding companies exists, effective and fair multi-environment variety trials are of utmost importance to motivate investment in breeding. The objective of this study was to use genotype main effect plus genotype by environment interaction (GGE) biplot analysis to evaluate test locations in terms of discrimination ability, representativeness and desirability, and to investigate the presence of multiple mega-environments in cotton production in the Yangtze River Valley (YaRV), China. Four traits (cotton lint yield, fiber length, lint breaking tenacity, micronaire) and two composite selection indices were considered. It was found that the assumption of a single mega-environment in the YaRV for cotton production does not hold. The YaRV consists of three cotton mega-environments: a main one represented by 11 locations and two minor ones represented by two test locations each. This demands that the strategy of cotton variety registration or recommendation must be adjusted. GGE biplot analysis has also led to the identification of test location superior for cotton variety evaluation. Although test location desirable for selecting different traits varied greatly, Jinzhou, Hubei Province, China, was found to be desirable for selecting for all traits considered while Jianyang, Sichuan Province, China, was found to be desirable for none.

This research classified vegetation types and evaluated net primary productivity (NPP) of southern China’s grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations (9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1 200 g C m-2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1 200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest (<600 g C m-2 yr-1). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1 000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest (48.44 Tg C), and mixed grassland class was the second (16.54 Tg C), followed by alpine grassland class (3.22 Tg C), with tundra grassland class being the lowest (0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest (34.81 Tg C), followed by sparse forest brush (16.54 Tg C), and montane meadow was the lowest (0.01 Tg C).

Upland red soils have been identified as major CO2 and N2O sources induced by human activities such as fertilization. To monitor characteristics of soil surface CO2 and N2O fluxes in cropland ecosystems after continuous fertilizer applications over decades and to separate the respective contributions of root and heterotrophic respiration to the total soil CO2 and N2O fluxes, the measurements of soil surface CO2 and N2O fluxes throughout the maize growing season in 2009 were carried out based on a fertilization experiment (from 1990) through of the maize (Zea mays L.) growing season in red soil in southern China. Five fertilization treatments were chosen from the experiment for study: zero-fertilizer application (CK), nitrogen-phosphorus- potassium (NPK) fertilizer application only, pig manure (M), NPK plus pig manure (NPKM) and NPK with straw (NPKS). Six chambers were installed in each plot. Three of them are in the inter-row soil (NR) and the others are in the soil within the row (R). Each fertilizer treatment received the same amount of N (300 kg ha-1 yr-1). Results showed that cumulative soil CO2 fluxes in NR or R were both following the order: NPKS>M, NPKM>NPK>CK. The contributions of root respiration to soil CO2 fluxes was 40, 44, 50, 47 and 35% in CK, NPK, NPKM, M and NPKS treatments, respectively, with the mean value of 43%. Cumulative soil N2O fluxes in NR or R were both following the order: NPKS, NPKM>M>NPK>CK, and soil N2O fluxes in R were 18, 20 and 30% higher than that in NR in NPKM, M and NPKS treatments, respectively, but with no difference between NR and R in NPK treatment. Furthermore, combine with soil temperature at -5 cm depth and soil moisture (0-20 cm) together could explain 55-70% and 42-59% of soil CO2 and N2O emissions with root interference and 62- 78% and 44-63% of that without root interference, respectively. In addition, soil CO2 and N2O fluxes per unit yield in NPKM (0.55 and 0.10 kg C t-1) and M (0.65 and 0.13 g N t-1) treatments were lower than those in other treatments. Therefore, manure application could be a preferred fertilization strategy in red soils in South China.

Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical (1990-2005) observations on four agricultural long-term experiments in China (Changping, Chongqing, Gongzhuling and Qiyang) under four different fertilizations, i.e., no-fertilizer (control), sole chemical nitrogen fertilizer (FN), sole chemical phosphorous and potassium fertilizers (FPK) and chemical nitrogen, phosphorous and potassium fertilizers (FNPK). The significant decline in topsoil pH was caused not only by chemical N fertilization (0.29 and 0.89 ΔpH at Gongzhuling and Qiyang, respectively) but also by chemical PK fertilization (0.59 ΔpH at Gongzhuling). The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P (168-599%)>available K (16-189%)>available N (9-33%). The relative rate of soil pH decline was lower under long-term judicious chemical fertilization (-0.036-0.034 ΔpH yr-1) than that under long-term sole N or PK fertilization (0.016-0.086 ΔpH yr-1). Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.

Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture. A pot experiment was conducted at Jilin Agricultural University, Jilin Province in northeast China to discover the influence of herb residue, animal excrement, woody residue, animal remnant on fulvic acid (FA) composition and structure using differential thermal analysis-thermogravimetric (DTA-TG), fourier transform infrared spectroscopy (FTIR) and elemental analysis. DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend: CK>herb residue>animal excrement>woody residue=animal remnant, and the most weight loss was observed in animal excrement. Moreover, the second exothermic reaction of CK- and animal excrement-FA was presented as double peaks, the order of weight loss in that area was animal remnant>CK>woody residue>animal excrement>herb residue. According to FTIR, herb residue displayed higher adsorption intensity at 2 950, 1 420, 1 240 and 1 030 cm-1, animal excrement was in reverse. At the same time, herb residue- and animal excrement-FA had an absorption peak at 1 720 cm-1, while other organic materials didn’t have this peak. As elemental analysis showed, FA isolated from various treatments was significantly distinct. It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.

Nitrogen (N) fertilizer experiments were conducted to investigate the optimal subtending leaf N concentration for fiber strength, and its relationship with activities of key enzymes (sucrose synthase and β-1,3-glucanase) and contents of key constituents (sucrose and β-1,3-glucan) involved in fiber strength development in the lower, middle and upper fruiting branches of two cotton cultivars (Kemian 1 and NuCOTN 33B). For each sampling day, we simulated changes in fiber strength, activity of sucrose synthase and β-1,3-glucanase and levels of sucrose and β-1,3-glucan in response to leaf N concentration using quadratic eqs.; the optimal subtending leaf N concentrations were deduced from the eqs. For the same fruiting branch, changes in the optimal leaf N concentration based on fiber development (DPA) could be simulated by power functions. From these functions, the average optimal subtending leaf N concentrations during fiber development for the cultivar, Kemian 1, were 2.84% in the lower fruiting branches, 3.15% in the middle fruiting branches and 3.04% in the upper fruiting branches. For the cultivar, NuCOTN 33B, the optimum concentrations were 3.04, 3.28 and 3.18% in the lower, middle and upper fruiting branches, respectively. This quantification may be used as a monitoring index for evaluating fiber strength and its related key enzymes and constituents during fiber formation at the lower, middle and upper fruiting branches.

Metaflumizone is a novel sodium channel blocker insecticide, which has been registered for controling the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) in China. It is unavoidable for DBMs to be exposed to sublethal dose of metaflumizone in brassicaceous vegetable field. Sublethal effects of metaflumizone at LC15 (1.06 mg L-1) and LC25 (2.03 mg L-1) on the biological characteristics were investigated. Pupation rate, pupal period and pupal weight were significantly declined comparing with the control (P=0.05) when third instar larvae were exposed to LC15 and LC25 of metaflumizone. Comparing the control group to LC15 and LC25 treatment groups, there were significant differences in the development periods of eggs, first instar larvae, pupae and total preoviposition period. The peak of age-specific fecundity in LC15 and LC25 treatment groups was lagged behind control group. Mean values of intrinsic rate of increase (rm), net reproductive rate (R0) and finite rate of increase (λ) observed from the LC15 and LC25 treatment groups were lower than those from the control group. But mean values of gross reproduction rate (GRR) was not different. The mean generation time (T) of the treatment groups was prolonged. Whether sublethal doses of metaflumizone could stimulate reproduction in the long term needs further investigation on continuous generations.

Grassland plays an important role in the global carbon cycle and climate regulation. However, there are still large uncertainties in grassland carbon pool and also its role in global carbon cycle due to the lack of measured grassland biomass at regional scale or global scale with a unified survey method, particular for below-ground biomass. The present study, based on a total of 44 grassland sampling plots with 220 quadrats across Ningxia, investigated the characteristics of above-ground biomass (AGB), below-ground biomass (BGB), litter biomass (LB), total biomass (TB) and root:shoot ratios (R:S) for six predominantly grassland types, and their relationships with climatic factors. AGB, BGB, LB and TB varied markedly across different grassland types, the median value ranging from 28.2-692.6 g m-2 forAGB, 130.4-2036.6 g m-2 for BGB, 9.2-82.3 g m-2 for LB, and 168.0-2 681.3 g m-2 for TB. R:S showed less variation with median values from 3.2 to 5.3 (excluding marshy meadow). The different grassland types showed similar patterns of biomass allocation, with more than 70% BGB for all types. There is evidence of strong positive effects associated with mean annual precipitation (MAP) and negative effects associated with mean annual temperature (MAT) on AGB, BGB, and LB, although both factors have the opposite effect on R:S.