【摘要】 【目的】探明硅提高小麦抗寒性的生理机制。【方法】采用水培试验,以抗寒性不同的两个小麦品种(临麦2号,高抗和扬麦5号,低抗)为材料,研究了不同硅处理(0、0.1和1.0mmol·L-1Si)对低温胁迫条件下小麦幼苗光合作用、叶绿素和可溶性糖含量的影响。【结果】加硅处理显著提高小麦体内硅含量,低温胁迫条件下,高抗品种临麦2号体内硅含量显著高于低抗品种扬麦5号;低温胁迫条件下,小麦幼苗的光合作用显著受到抑制,扬麦5号的下降速率要大于临麦2号。施硅能够提高低温胁迫条件下小麦幼苗净光合速率(Pn)、气孔导度(Gs)、气孔限制值(Ls)、水分利用率(WUE);蒸腾速率(Tr)在低温胁迫条件下降低,加硅处理后蒸腾速率下降。低温胁迫条件下两个小麦品种的叶绿素含量和叶绿素a/b的比值下降,可溶性糖含量显著升高;施硅能减缓低温胁迫对叶绿素含量、Chla/Chlb比值和可溶性糖含量的影响。【结论】低温胁迫下,高抗小麦品种加硅处理后体内较高的硅含量是高抗品种较低抗品种具有更强抗寒性的原因之一。更多还原

【Abstract】 【Objective】The objectives of this study were to gain better insight into the biological mechanisms of silicon-enhancement of cold tolerance in wheat. 【Method】Hydroponic experiments were performed to investigate the effects of exogenous silicon (Si) on the changes in photosynthetic and physiological parameters in two winter wheat (Tritium aestivum L.) cultivars, Linmai 2 (resistant) and Yangmai 5 (susceptible), under cold stress. Wheat seedlings were treated with 0, 0.1or 1.0 mmol·L-1 Si, and were then subjected to cold stress. 【Result】 Exogenous Si increased shoot Si content of both wheat cultivars with Si content being higher in Linmai 2 than in Yangmai 5. The leaf photosynthesis was significantly inhibited under cold stress, but significantly enhanced by added Si. In comparison with the control, cold stress induced a decline in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), stomatal limitation value (Ls) and water utiliy efficiency (WUE) in seedlings. However, exogenous Si significantly increased the Pn, Gs and Tr. The transpiration rate was decreased under cold stress and even lower in Si-supplied cold treatment than in the Si-untreated one. The content of chlorophyll, the ratios of Chl a/Chl b and the content of soluble sugar were decreased under cold stress. Exogenous Si decreased the content of soluble sugar significantly in both cultivars, whereas it did not significantly increase the contents of chlorophyll or the ratios of Chl a/Chl b. 【Conclusion】The higher shoot Si content in the cold-resistant cultivar treated with Si can partly explain why the cold-resistant cultivar is more resistant than the cold-susceptible cultivar under cold stress.更多还原