模拟盐碱胁迫对小麦幼苗茎长生长的影响

农田土壤盐碱化已经成为影响小麦种子萌发及幼苗生长的一个重要因素。利用NaCl和Na2CO3模拟盐碱胁迫对小麦种子萌发期茎长生长的影响实验表明,4种小麦的茎长生长在大部分复合浓度条件下表现出显著差异,并随着浓度的增加而表现出降低的趋势,与无盐碱胁迫的茎长生长表现相一致,其幼苗茎长生长的耐盐碱性高低次序为:济南17>淄麦12>邯6172>泰山9818。在单一盐或碱胁迫条件下,小麦的茎长生长总是随着NaCl或Na2CO3浓度的增加而表现出不同程度的降低。无论以NaC l浓度增加为主还是以Na2CO3浓度增加为主的情况下,小麦幼苗的茎长生长均随着浓度的增加受到明显的抑制作用。盐碱复合胁迫对小麦幼苗期茎长生长的影响机理还缺乏生物学及生理学上的解释,仍需要进行深入研究。

Developmental Differences, Yield and Late Blight （Phytophthora infestans）Infection of Potato Plants Grown under Organic and Conventional Systems

In the years 2008-2010, an experiment was conducted Phytophthora infestans under organic and conventional production on four potato cultivars differing in maturity and resistance to systems. During the growing season, plant growth was evaluated by measuring plant height, stem number, leaf and stem biomass and leaf area index （LAI）. Photosynthetic active radiation （PAR） absorption and leaf chlorophyll content were also measured. The rate of late blight development, tuber yield, tuber size, and harvest index was assessed. There were significant differences between the two production systems in the most studied parameters. Plants growing in the organic system were characterized by reduced plant development compared to plants growing in the conventional system. As a result of lower plant growth, tuber yield was reduced by 22% and tuber size was smaller. Harvest index did not differ significantly between production systems. A positive effect of the reduced development of aboveground plant parts in the organic system was later appearance of the first symptoms of late blight and slower spread the disease.