不同灌水方式对砂姜黑土小麦中后期生长及产量的影响

在人工防雨篷下研究了前期不同灌水处理对砂姜黑土小麦中后期生长、光合生理及产量的影响,以期为该区小麦增产和水分高效利用提供科学依据和理论帮助。结果表明,灌1水条件下小麦叶片长宽和单茎干物重随灌水日期的推迟呈先增加后下降的趋势,并以生育前期水分充足处理CK最高,W5100d(出苗后100 d灌水)处理次之,且总灌水量一致下小麦生育前期灌1水和灌2水效果间的差异不显著。生育前期适当推迟灌水日期有利于增加小麦生育中后期的叶面积指数和叶绿素含量,且灌浆中期W5100d处理的叶面积指数和叶绿素含量高于CK。小麦生育前期适当推迟灌水日期亦有利于降低植株蒸腾速率改善小麦光合特性,其中W5100d处理的光合速率比对照CK增加了11.4%。W5100d与CK处理的产量差异不显著,分别为6 955.40,7 102.67 kg/hm2,但两者产量明显高于其他灌水处理。相关分析表明,小麦叶片叶绿素含量、光合速率与单茎干物重和产量间皆呈直线显著正相关关系。研究得出,小麦生育前期适当延长灌水日期有利于改善小麦中后期生长发育、光合特性及产量,且总灌水量一致下灌水次数效果间的差异不显著。     

Barley mutants with increased tolerance to aluminium toxicity

Acid soil and associated aluminium toxicity are considered as the number one abiotic factor limiting crop production. Over 2 billion hectares of acid soils exist world-wide, both in tropical and moderate climatic zones. In Poland acid soils represent up to60% of arable land. At soil pH < 5.0 Al ions become soluble in water and toxic to plants. Genetic improvement of Al tolerance in crops is the only alternative to soil liming, a traditional but short term and expensive agricultural cure to raise soil pH. Of the various cereals, barley is the most sensitive to Al toxicity. The known sources of Al tolerance in barley are limited to old cultivars and landraces. While they represent multiple alleles of a single locus, there is no potential to improve Al tolerance through recombination of non-allelic additive genes. In the Department of Genetics, Silesian University we have employed induced mutations for rapid creation of variability for Al tolerance in barley. Thirteen mutants with increased levels of tolerance to Al toxicity have been selected in M₃ generation after mutagenic treatment of four barley varieties with N-methyl-N-nitroso urea (MNH) and sodium azide. Six further Al tolerant mutants were identified in the collection of semi-dwarf mutants of the Department. All selected mutants confirmed Al tolerance with the use of three different methods of screening, i.e., root re-growth, root tolerance index and hematoxylin staining. Fourteen mutants exhibited significant root re-growth after 48 hour incubation with 3 ppm Al⁺³ and two of them, namely RL819/2 and RL820/6 were tolerant even to 6 ppm Al⁺³. Crosses of two selected mutants with their respective parent varieties indicated that Al tolerance in each mutant was controlled by a single recessive gene. Out of three methods tested, the root re-growth method facilitated by hematoxylin staining proved to be the most reliable technique for large scale testing. Double treatment with MNH or combined treatment with sodium azide and MNH and 6hinter-incubation germination between treatments were the most successful treatment combinations for induction of aluminium tolerance in barley. This revised version was published online in August 2006 with corrections to the Cover Date.     

6102B型柴油机曲轴三维有限元模态分析与试验研究

采用三维有限元方法对6102B型柴油机的曲轴进行了动态特性分析和研究，在计算中充分考虑了主轴承刚度对曲轴振动特性的影响，采用了具有约束的有限元模型，通过计算，得出了该曲轴在1kHz内的固有频率分布情况，并对600Hz以内的振型情况进行了分析，为了验证计算的合理性，经过6102B型柴油机曲轴振动情况的实际测试，发现计算结果和试验结果基本吻合，从而为今后曲轴的振动计算和有限元分析提供了新的计算依据。     

草地生态系统健康研究述评

阐述了草地生态系统健康的研究进展、存在问题和发展趋势,重点介绍了评价的指标体系和方法,包括结构功能指标体系法、综合指标体系及10多种方法的特点和适用情况.同时对于指标的筛选、权重的确定、标准的划分等难重点问题给出了建议.提出了用多种方法来评价同一研究对象来进行比较和矫正的观点,并强调形成集自然、经济、社会、人类健康为一...     

兽用消毒剂二氧化氯检测方法的研究进展

二氧化氯由于对细菌、病毒有广谱、快速、高效和安全的杀灭特点和优势,在畜禽养殖业中得到越来越广泛的应用。本文主要对目前国内外已有的二氧化氯检测方法进行阐述,并对各方法的优缺点进行评述。     

不同嫁接方法对甜瓜枯萎病抗性的影响及其生理响应

本文研究了插接、断根嫁接和靠接3种嫁接方法对甜瓜枯萎病抗性的影响。结果显示,3种嫁接方法均能显著提高甜瓜的抗枯萎病能力．但3种嫁接方法之间无显著差异。接种枯萎病菌后,嫁接苗根系活力、叶绿素含量、根系中SOD、POD、PAL活性显著高于自根苗,而MDA含量、相对电导率显著低于自根苗。以上结果表明,嫁接是提高甜瓜对枯萎病抗性的有效措施,但不同嫁接方法对甜瓜枯萎病抗性无显著影响;嫁接苗通过抗氧化系统和PAL活性的提高抵御了枯萎病菌侵染后所致的膜脂过氧化伤害,维持了根系和叶片的正常生理功能,从而提高了嫁接苗对甜瓜枯萎病的抗性。     

发酵法生产虫草素研究进展

综述液体和固体发酵法生产虫草素的研究状况,并展望其发展趋势.     

杜仲生长节律与施肥技术简报

杜仲高生长以4－7月份生长最快，6月份达最高峰；径生长以5－7月为旺盛期，其中6、9月各有一次生长高峰；杜仲林地施肥以4－5月为最佳；施肥量为一个区间，且因树龄而异；施肥按坡台地和平地进行沟施和穴施。     

小径木白桦锯材不同加热方式下含水率的变化

讨论小径木白桦锯材在连续加热和间歇加热方式下含水率的变化规律.结果表明:小径木白桦锯材的干燥速率在含水率15%以后明显降低,前期干燥过程锯材的干燥速率比后期的高2～3倍;间歇加热方式有利于内部水分向外扩散,间歇时间对干燥速率的影响很小;干燥过程中锯材厚度方向上的含水率梯度呈不对称分布,这与小径木的心材占较大比例有一定关系;间歇加热减少了锯材内含水率梯度的变化值,同时减少了应力的产生,从而提高了干燥质量.