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作 者 ：张艳嫣1,陈 丹1,谭艳玲1,王 丹1,沈伟桥2,周建华2,黄冲平2*

期 刊 ：西北植物学报 2013年 4期 页码：747~754

关键词：铁皮石斛；硒；低温胁迫；抗氧化生理；保护酶活性；

Keywords:Dendrobium candidum, selenium, low temperature stress, antioxidative physiology, protective enzymes activity,

摘 要 ：以3个不同品系的铁皮石斛幼苗为材料,分别于叶面喷施不同浓度的亚硒酸钠溶液处理,并结合人工控温生长条件下的低温胁迫试验,探讨外源硒对铁皮石斛幼苗耐冷性和恢复生长能力的影响作用及其与有关抗氧化生理指标间的关系。结果表明:（1）耐冷性表现较强的品系其幼苗在低温胁迫下的叶绿素、MDA及脯氨酸含量变化幅度相对小于耐冷性较弱的品系。（2）适量浓度（0.05~0.10 mg·L^-1）外源硒处理对低温胁迫下铁皮石斛幼苗叶绿素降解具有缓解效应,可降低MDA含量,增加脯氨酸含量,同时显著提高GSH-AsA循环活性,从而提高铁皮石斛幼苗的耐冷性,但过高浓度的外源硒处理(＞0.20 mg·L^-1)则效果相反。（3）低温胁迫解除后,0.10 mg·L^-1的外源硒处理能引起铁皮石斛‘ZD-1’幼苗中AsA含量显著下降并促进其GSH合成积累,有效提升铁皮石斛幼苗在恢复生长期的综合抗氧化防御能力。

Abstract:In this study,three different strains of Dendrobium candidum seedlings were sprayed with different concentrations sodium selenite (Na₂SeO₃) solution on leaves and treated with low temperature stress under artificial temperature control growth conditions,then the effects of exogenous selenium on cold tolerance and recovery growth ability of D.candidum seedlings and their relationship with the relevant antioxidant physiological indexs were discussed.The result showed that:(1)Under low temperature stress,chlorophyll content,MDA content and proline content in the D.candidum seedlings with superior cold tolerance changed less than the strain with weaker cold tolerance.(2)Appropriate concentration of exogenous selenium(0.05~0.10 mg·L^-1) spraying treatment could alleviate the effect of chlorophyll degradation,also caused seedling antioxidant GSH-AsA activity significantly increase,meanwhile it increased the proline content and decreased the MDA content,improved the cold tolerance of D.candidum seedlings.However,the high concentration of exogenous selenium (＞0.20 mg·L^-1) treatment leaded to an opposite result.(3)After low temperature stress treatment,exogenous selenium (0.10 mg·L^-1) treatment could decrease the AsA content of seedlings significantly,but could promote the synthesis and accumulation of GSH,and effectively protected the comprehensive antioxidative capability of D.candidum ‘ZD-1’ seedlings in recovery growth period.

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