节能环保型中耕机的设计

针对现有中耕除草机械作业成本高、维修不便、污染环境等缺陷,开发了SL-30型手扶乘坐式直流电动多功能中耕作业机械,该机既可进行玉米、大棚蔬菜及林果等中耕除草作业,又可以作为动力牵引其他作业机具.介绍了设计技术要求、总体方案的确定以及主要零部件的设计,简要分析了生态和经济效益.     

苏家屯区水稻收获机械化适宜经营规模分析

合理的机具配备是水稻生产机械化效益充分发挥的前提。以苏家屯区水稻机械化收获作业为例,调查分析两种水稻收获机的技术参数与经济参数,通过建立数学模型,确定其适宜经营规模,为苏家屯区水稻收获机具的合理选择及配备提供依据。     

农杆菌介导的马铃薯茎段遗传转化体系优化研究

以甘肃主栽品种的茎段为外植体,研究了不同转化条件(菌液浓度、感染时间、预培养及共培养时间)对转化效率的影响,以及选择压和培养基对抗性出芽的影响,初步建立了马铃薯品种“陇薯3号”和“台湾红皮”的遗传转化体系并获得了转化植株。卡那霉素生根筛选和PCR鉴定结果表明,再生的转化植株假阳性率比较高,要获得预期的转基因植株群体需加大遗传转化工作中转基因植株的数量。     

棉花叶片衰老生理研究进展

随着转基因棉花的大面积推广,棉花早衰发生加重,已经成为制约棉花发展的重要因素,有关早衰的研究成为学者关注的焦点。综述了近年来国内外有关棉花叶片衰老生理的研究结果,主要包括衰老过程中各种生理生化指标的变化特征,以及防止棉花叶片衰老的各种调控措施。文中概述了一些常用的棉花叶片衰老生理生化指标,如叶绿素、蛋白质、丙二醛(MDA)、活性氧清除系统(SOD、POD、CAT)、激素(生长素、细胞分裂素、赤霉素、脱落酸、乙烯、多胺)等。大量研究表明在棉花叶片衰老过程中叶绿素、蛋白质含量急剧下降,而MDA含量快速上升,活性氧清除系统酶活性产生相应的变化,各内源激素的含量也具有各自变化特点。针对棉花早衰的生理过程,通过采用植物生长调节剂,氮、钾、钙3种肥料,以及水分、光照、温度、气体等环境因子的调节措施来预防叶片早衰以及对出现叶片早衰后的稳产措施。最后对棉花叶片早衰的研究方向进行了展望。     

Strength and Microstructure of Sulphoaluminate Cement Containing Ultra- Fine CaCO3

The existence of ettringite in sulphoaluminate cement hardened paste is mainly in the form of pole-like crystal,which causes unfavorable effect on the cement.In this paper the strength and microstructure of the sulphoaluminate cement containing ultra-fine CaCO_3 weze discussed.Experimet results show that the strength of sulphoaluminate cement was obviously improved by adding 3% of ultra-fine CaCO_3.After curing for 28d,the compressive strength of cement paste and mortar is 100.6MPa and 94.1MPa respectively,and the bending strength of the mortar reached 12.5MPa.SEM study on hardened paste of sulphoaluminate cement containing ultra-fine CaCO_3 showed that its structure was dense and homogeneous,there was hardly any massive crystall detected.     

番茄分子标记开发进展

分子标记辅助选择为选育由多基因控制的或易受环境影响的性状提供了一条有效的途径.番茄分子标记的开发工作已经进行了三十多年,到目前为止已有2 300多个不同类型的分子标记被开发和定位到12条染色体上.很多文献对这些分子标记的特点及其在番茄遗传育种中的应用进行了综述,但对其开发过程却很少提及.因此本文就主要类型的番茄分子标记的开发进展进行概括并分析其开发前景.     

Rapid survey for presence of a blast resistance gene Pi-ta in rice cultivars using the dominant DNA markers derived from portions of the Pi-ta gene

The Pi‐ta gene in rice confers resistance to strains of the blast pathogen Magnaporthe grisea (Herbert) Borr. (anamorph Pyricularia oryza Cav.) containing the corresponding avirulence gene AVR‐Pita in a gene‐for‐gene fashion. The Pi‐ta gene is a typical nucleotide‐binding site type resistance gene. Nucleotide sequences distinguishing the resistant Pi‐ta and susceptible pi‐ta alleles were previously identified and used for developing DNA markers for a resistant Pi‐ta haplotype and three susceptible pi‐ta haplotypes. In the present study, the existence of the Pi‐ta gene in 141 rice germplasm accessions was rapidly determined using these markers, and the results were confirmed by inoculating rice germplasm with an M. grisea strain containing AVR‐Pita. The Pi‐ta gene was found in accessions from several major rice producing countries, including China, Colombia, Japan, Vietnam, the Philippines, Iran and the United States. The usefulness of DNA markers for rapid determination of the genotype of rice germplasm was thus demonstrated. The Pi‐ta gene also was found in rice cultivar known to contain the Pi‐ta² gene, although the allelic relationship of these genes remains to be determined. The presence of the Pi‐ta gene in landrace cultivars in several different geographical locations, the Philippines and Vietnam, other indica rice cultivars in China and Colombia suggest that the Pi‐ta gene may have spontaneously originated in indica rice cultivars. These results are useful for incorporating the Pi‐ta gene into advanced breeding lines by marker‐assisted selection for rice breeding programmes worldwide.     

DCA、CCA和DCCA三种排序方法在中国草地植被群落中的应用现状

排序是用来分析植被与环境之间生态关系的重要手段。该文主要是对除趋势对应分析（DCA）、典范对应分析（CCA）和除趋势典范对应分析（DCCA）这三种排序方法进行总结，讨论它们在中国草地植被群落研究中的应用现状，并得出除趋势对应分析与聚类分析结合使用效果比较好，主要是用来揭示群落之间的关系，并且在实际的应用中也比较多，而典范对应分析和除趋势典范对应分析在揭示种与环境关系方面具有明显的优势，但是由于某些条件的限制，在实际研究中应用的比较少。可见这几种排序方法在实际应用中具有一定的优势，所以应该加强这方面的应用，更加深入的研究草地植被群落，以期对草地生态学及草地植被群落生态关系的研究工作发挥重要的借鉴作用。     

The Application of TDZ in Enhancing Regeneration of Transgenic Plants

At present, transgenic plants are globally grown. Availability of a reliable regeneration system predominantly from a single transformed cell is the prerequisites for gene transfer, but regeneration is still a key problem （Wenzel, 2006）. The application of genetic modification technology in plants is closely related to the efficiency of the regeneration protocol. Shoot formation is oilen enhanced by the combination of auxins and cytokinins. TDZ （Thidiazuron, N-phenyl-N＇-1,2,3-thiodiazol-5-ylurea）, a non-purine, has been shown to promote differentiation of organized centers of growth in cultured tissues at much lower concentrations, and shoot regeneration occurs with an efficiency comparable to or greater than that of other cytokinins （Fiola et al., 1990）. By addition of TDZ, a series of plants which were difficult to culture in vitro or less sensitive to plants growth regulators obtained somatic embryos and regenerated plants, some of them have become the eminent transformation system for genetic engineering. TDZ has been reported to be very efficient in stimulating adventitious shoot production in several recalcitrant plants. TDZ is considered as a potential growth regulator for in vitro shoot regeneration and somatic embryogenesis of several crops. This review summarized how the new growth regulator TDZ to affect the regeneration of transgenic plants.     

发展生态农业 促进农业可持续发展

山西省地处黄土高原,农业生产条件差,环境污染也比较严重。要改变农业生产的现状,必须走可持续农业发展的道路。生态农业是在保护环境的基础上,合理优化配置各种生物资源和自然资源的一种高效率的农业生产模式,只有走生态农业的道路才能实现农业的可持续发展。