Na+ Retention in the Root is a Key Adaptive Mechanism to Low and High Salinity in the Glycophyte,Talinum paniculatum (Jacq.) Gaertn. (Portulacaceae)

Talinum paniculatum is an important leafy vegetable and medicinal plant, used in many parts of South America, Africa and Asia. Its adaptation to abiotic stress has received little attention and therefore worthy of interest, especially as environmental conditions are rendering arable lands increasingly unfavourable for agriculture. Therefore, this study was undertaken to examine the influence of salt stress on the vegetative growth of the plant by subjecting seedlings to 0, 25, 50, 100, 200 and 300 mm NaCl stress for 10 days. The dry weight, ion concentrations, relative water content, oxidative damage, proline, osmotic potential and some antioxidants were determined. The plants were found to retain Na⁺ mainly in the root, with less affected leaf K⁺ concentration, and consequently very low shoot Na⁺/K⁺ ratios (<0.2) under all the stress treatments. The proline content significantly increased under the 100–300 mm treatments (18‐ to 244‐fold), with a corresponding significant reduction in osmotic potential and hence high osmotic adjustment. The antioxidant enzyme activities and non‐enzyme antioxidants showed significant increase only under the highest salinity. Taken together, these results suggest that shoot Na⁺ exclusion is characteristic of this plant and is mainly responsible for its adaptation to low salinity.     

基于模糊控制的牵引电机冷却风机变频节能控制系统

介绍了一种求解旅行商问题的新算法“最小调整法”，给出了该算法求解旅行商问题的具体步骤以及有效性证明，对算法的复杂性及近似程度进行了分析.最后通过典型算例进行了检验说明.与经典算法相比，新算法体现了简单易行的特点，对求解旅行商问题具有一定的启发意义.     

产业结构优化理论综述及新进展

产业结构优化在经济学界是一个长久不衰的热点问题。经济发展到一定阶段,必然伴随着产业结构的调整和优化。在简要回顾了有关产业结构优化理论文献的同时,对近年来国内外在产业结构优化研究方面的若干新进展加以梳理和评述。     

河北滨海平原区种植业结构调整探析

以1985-2010年统计数据为基础,运用定量与定性相结合的分析方法,对河北滨海平原区1985-2010年种植结构调整过程进行了初步研究,明确了该区不同时期粮食作物、油料作物、棉花、蔬菜、水果等作物的结构和变化趋势,分析了该区种植业结构调整的内在原因及动力,并对河北滨海平原区未来种植结构调整的方向和重点进行了讨论.     

加入WTO与中国农业政策调整

首先揭示了中国现行农业政策的主要特征，然后以WTO《农业协议》为参照，指出中国农业政策在市场准入，国内支持及卫生检疫措施等方面的相悖之处，最后就新时期中国农业政策调理 提出如下主要建议：1．农业政策的首要目标应从保证供应转向提高农民收入；2．农业政策的主要手段应从边境措施转向国内支持；3．国内支持应从价格支持力向收入支持；4．政策应加大对农业的支持力度。     

论农业结构调整的资金投入

农业结构调整是我国当前农村工作的一项重要任务，分析了农业结构调整中资金投入存在的问题、原因，并从金融体制改革、政府宏观调控、农户与乡镇企业积累方面，提出了解决农业结构调整资金投入的对策。     

棉花渗透调节与蒸腾速率的日变化关系

大田正常供水条件下，随１ｄ内光照和温度增加，棉花叶水势及渗透势下降，最低水势为－１１．４巴，渗透势为－１４．２巴，其膨压值为２．８巴，表现出渗透调节作用。气孔导度在中午一段时间最高，而蒸腾速率最高点在１２∶００时，之后下降，表明水分胁迫下产生渗透调节作用，使叶片保水力增加，蒸腾减弱。Ｋ＋和可溶性糖变化，以渗透势下降最低时积累最多，是棉花干旱时主要的渗透调节物质。     

A comparison of several procedures for mass selection in winter rye. II. What are the merits of adjusting phenotypic values?

Summary To get an improved impression of the genotypic value of individual plants the literature suggests to adjust their phenotypic values according to a moving mean correction or by means of an analysis of covariance, where the mean phenotypic value calculated across neighbours is used as the concomitant variable. In the present paper it is shown that the theoretical merits of these adjustments are promising: they eliminate the contribution due to the trend in soil fertility from the phenotypic value. In an experimental verification actual merits did, however, not show up.It is concluded that interplant competition is the main cause for the failure of the studied adjustments. These may be effective in virtual absence of intergenotypic competition. Thus, in case of single plant selection an extremely low plant density would be required, whereas selection among lines or families would require evaluation by means of multi-row plots.     

高原沟壑区高效农业生态经济系统研究Ⅰ调整农村产业结构

１０年科技攻关，王东沟小流域产业结构发生了显变化，由历史以种植业为主的一元结构，发展到“七五”时以种植业，副业为主的二元结构，现已发展到种植业、果业、工副业三元结构。农业产业三元结构增加了农业生态系统的稳定性、抗逆性。在连续干旱的气候条件下，粮食生产持续发展，农民收入成倍增加，生态环境得到明显改善，经济效益，社会效益，生态效益得以同步实现。     

平面测量导线闭合差调整一步法

在平面测量中,导线平差,先平内角闭合差,后平座标增量闭合差,分为两个步骤进行。在座标增量闭合差调整中,又分为按边长比例分配、按座标增量值大小比例分配及按累积边长比例分配。这些方法都是简易计算近似平差法,由于内角闭合差调整,会过多干扰导线边的方向角。因而笔者提出:省略内角闭合差调整这一步,将二步简化为一步,简称一步法,使计算更为简化与完善。