硅对植物抗旱性影响的研究进展.doc

硅对植物抗旱性影响的研究进展 　　摘要：土壤水分不足是限制植物生长、影响植物产率的主要因素，通过破坏细胞的离子渗透平衡发挥作用。虽然硅通常被认为不是植物生长的必需元素，但是植物吸收硅后在一定程度上能够缓解生物和非生物胁迫。因此，使用硅元素能够在不利的气候和土地环境中提高作物的产量。大量的试验结果已经验证了硅的作用，但是硅发挥作用的机制还没被系统地讨论。因此，查阅了硅在植物中吸收、运输和积累以及硅如何能减轻干旱胁迫方面的研究情况。主要观点有以下几个方面：①硅元素的吸收有主动运输和被动运输两种形式。但是更多的硅转运方式仍不太明确，硅运输的过程需要进一步阐明。②硅在抗旱性方面的机制在生理生化层面上得到了部分的阐明，包括能增加根系水分的摄入、保持营养平衡、减少叶片的水分流失、促进光合速率和通过增加抗氧化酶活性、非酶抗氧化剂的活性，提高抗氧化能力。③硅能够在胁迫条件下调控植物内激素的平衡，然而硅在增加抗逆性相关信号转导和基因表达方面的机制仍有待探索。 　　关键词：植物；干旱胁迫；硅 　　中图分类号：Q945.78 文献标识码：A 文章编号：0439-8114（2016）10-2449-04 　　DOI：10.14088/ki.issn0439-8114.2016.10.001 　　Abstract： Soil drought is major abiotic factors that limit crop growth and productivity worldwide. Indeed， soil drought disrupts the cellular ionic and osmotic balance. Although silicon（Si） is generally considered nonessential for plant growth and developments， Silicon uptake by plants can alleviate both biotic and abiotic stresses. Silicon applica-tion could therefore improve crop production under adverse climate and soil conditions. Several reports have reviewed the benefits of silicon application on crop growth， but the mechanisms of silicon action have not been systematically discussed. Here， the authors review recent advances on silicon uptake， transport， and accumulation in plants and how silicon alleviates salinity toxicity and drought stress. The major points are the following：① both passive and active silicon uptake may coexist in plants， but more silicon transporters remain to be identified， and the process of silicon transport needs further clarification； ② the mechanisms for silicon mediated tolerance of salinity and drought have been extensively investigated at both physiological and biochemical levels， further more including increasing water uptake， i.e.， roots， maintaining nutrient balance， decreasing water loss from leaves， promoting photosynthetic rate. And it may improve antioxidant defense abilities by increasing the activities of antioxidant enzymes and the contents of non enzymatic antioxidants； ③ silic