多熟制水稻插秧机分插机构的研究

为了解决南方多熟制水稻移栽时对不同高度秧苗的适应性问题,对分插机构进行了研究。在选定最大适插苗高,并求得秧针端点运动轨迹后,计算确定了分插机构诸参数。经对该机构进行理论分析、验证和田间实插试验,证明对苗高10～30cm 秧苗具有良好的适应性。     

Single and joint acute toxicity of isocarbophos enantiomers to Daphnia magna

Although enantioselectivity in the toxicity of chiral pesticides has received considerable attention over recent years, how coexisting enantiomers interact with each other during their toxic action remains unknown. In this study, we attempted to resolve the enantiomers of a chiral organophosphate insecticide, isocarbophos, and investigated the acute toxicity of individual enantiomers and various enantiomer mixtures. Baseline enantiomeric separation of isocarbophos was achieved on a Chiralcel OD column with the mobile phase of n-hexane/isopropanol (90/10, v/v) at a flow rate of 0.8 mL/min. The resolved enantiomers were differentiated by their responses on a circular dichroism detector. The median lethal concentrations (LC 50) of racemate, (+)-enantiomer, and (-)-enantiomer of isocarbophos toward Daphnia magna were 13.9, 7.08, and 353 microg/L, respectively, after 48 h of static exposure, displaying a 50-fold difference between the enantiomers. Toxic unit (TU) analysis was employed to evaluate the joint toxicity of isocarbophos enantiomer mixtures. The calculated TU mix for the acute toxicity (48 h test) of various binary mixtures ranged from 0.83 to 1.04, suggesting a mode of additive effect. Further evaluation of available literature data for chiral organophosphorus insecticides showed that the joint toxicity of enantiomers may be additive, synergistic, and antagonistic. Therefore, when significant enantioselectivity exists for a chiral pesticide, it is important to also evaluate the interaction of enantiomers in the joint toxicity effect when enantiomers are present in a mixture.     

基于改进熵权TOPSIS法的江西省土地利用效益综合评价

基于成本效益分析、构建了包含农用地和建设用地两方面的土地利用效益综合评价指标体系,运用TOPSIS法并结合改进熵权法确定权重,对江西省11个地级市2008²010年农用地利用效益、建设用地利用效益和区域土地利用综合效益进行了定量评价,研究结果可为区域土地可持续利用提供科学依据。     

宁夏枣树花药离体培养再生体系的建立

采用宁夏3个特色枣树品种的花药为外植体,探索MS培养基中不同激素、激素的不同浓度配比对愈伤组织诱导、不定芽分化的影响,建立其愈伤组织诱导及不定芽再生体系。结果表明,细胞分裂素6-BA对宁夏枣树胚性愈伤组织诱导起重要作用,AgNO3对愈伤组织分化不定芽影响显著。经过正交试验分析得出,最佳诱导培养基为MS+6-BA 1.0 mg/L+2,4-D1.0 mg/L+IBA 0.4 mg/L;最佳分化培养基是：MS+6-BA 1.5 mg/L +IBA 0.6 mg/L +AgNO3 0.5 mg/L。在最佳诱导培养基中灵武长枣诱导率最高,达89.0%,在最佳分化培养基中同心圆枣分化率最高,达88.0%。     

美国乡村林业发展经验借鉴

在我国经济由高速增长向高质量发展转型的背景下,绿色产业发挥着不可替代的作用。而林业是我国最大的绿色产业,也是构成乡村经济的重要产业部门。文中从林业专业人才、林地管理和林权交易、资金扶持以及乡村产业多元化发展4个方面介绍美国在乡村林业发展的经验,提出促进我国乡村林业发展、推动林业产业扶贫的相关建议,以期为我国林业产业提升经济、社会和生态效益提供参考。     

谈评等中针叶材活节检量

本文针对GB／T114－1995《原木检验》标准中，有关针叶树材的活节，检量颜色较深，质地较硬部分（似黑眼珠）的尺寸问题，认为颜色较深、质地较硬是构造特征，节子尺寸应含最外圈年轮。检量似黑眼珠不符合国际惯例。     

济南玫瑰湖湿地生物多样性评价研究

在对玫瑰湖湿地物种现状进行统计分析的基础上,建立湿地生物多样性评价指标体系与赋值标准．从物种多样性和生态系统多样性两个指标对玫瑰湖’湿地生物多样性进行了评价。玫瑰湖湿地生物多样性总评分为68．5分,结果表明玫瑰湖湿地生物多样性处于一般水平。     

番石榴SRAP反应体系的建立与正交优化

采用正交设计方法,对影响番石榴SRAP反应体系的Mg2+、dNTPs、引物、Taq DNA聚合酶和模板DNA浓度等进行了优化,建立了适用于番石榴的SRAP反应体系。该优化的20 μL反应体系中包含2.5 mmol/L Mg2+,0.15 mmol/L dNTPs,0.4 μmol/L引物,1.5 U Taq DNA聚合酶和20 ng模板DNA。利用该优化体系通过64对SRAP引物组合对5份番石榴材料进行了SRAP-PCR扩增,结果表明SRAP引物及优化后的反应体系能够有效地用于番石榴种质资源鉴定及遗传多样性分析等研究。     

Expression and functional characterization of glutamine synthetase from giant freshwater prawn (Macrobrachium rosenbergii) under osmotic stress

The freshwater prawn, Macrobrachium rosenbergii naturally lives in the freshwater, though it migrates to the brackish water environment during spawning that claimed to be resistant on a broad range of saline fluxes. However, little is known about the osmoregulatory patterns and the effect of an enzyme glutamine synthetase (GS) in M. rosenbergii under stress. Here, we described the identification and functional characterization of GS from M. rosenbergii (Mr‐GS) at molecular and protein levels. The identified Mr‐GS was comprised of 361 amino acids that phylogenetically shared the highest identity with other crustaceans and predicted to contain Gln‐synt_C and Gln‐synt_N domains at the respective terminal regions. Tissue distribution analysis in M. rosenbergii revealed that the Mr‐GS was highly expressed in muscle, and commonly existed in other examined tissues in the following order gills > heart > stomach > brain > haemolymph. Whereas, the mRNA of Mr‐GS was significantly up‐regulated in the muscle and gill tissues following challenges with either hyper (0 → 13‰), or hypo (13 → 0‰) osmotic stress at 3, 6 and 12 hr. Furthermore, the level of Glutamine concentration was positively correlated with the GS mRNA and protein expression patterns in hyper‐osmotic stress, whereas in hypo‐osmotic stress a slight decrease in the gills and maintained a level in the muscle tissues at 3, 6 and 12 hr post‐treatments. Our findings suggest that Mr‐GS potentially exhibited the osmoregulation responses in the gill and muscle tissues of M. rosenbergii throughout the time of osmotic stress, which will benefit for future study on osmoregulation.