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作 者 ：王园园,尹翠翠,王广东*

期 刊 ：西北植物学报 2013年 4期 页码：735~740

关键词：杂交兰；二倍体；四倍体；高温胁迫；渗透调节物质；抗氧化酶；

Keywords:Cymbidium hybrid, diploid, tetraploid, high temperature stress, osmolytes, antioxidant enzymes,

摘 要 ：以二倍体杂交兰及其加倍后形成的四倍体为材料,研究了高温胁迫（40 ℃/30 ℃,光周期为12 h/d）处理对二倍体及其四倍体杂交兰幼苗叶片叶绿素含量、膜损伤程度、渗透调节物质含量以及保护酶活性等生理生化特性的影响,以明确其抗热性差异。结果显示:高温胁迫后,各材料叶绿素含量均随胁迫时间延长呈下降趋势,且四倍体杂交兰的下降幅度小于二倍体;两种倍性杂交兰叶片丙二醛(MDA)含量均增加，O^-·₂释放速率总体呈下降的趋势,但四倍体MDA含量增幅和O^-·₂释放速率始终低于二倍体;四倍体叶片脯氨酸、可溶性糖、可溶性蛋白质含量的增幅均大于二倍体,其SOD、CAT活性的增幅也均显著大于二倍体,但其POD活性的降幅则小于二倍体。研究表明,四倍体杂交兰具有较强的细胞渗透调节能力、蛋白质合成能力、蛋白质稳定性以及消除活性氧伤害的能力,耐热性强于二倍体。

Abstract:Seedlings from the tetraploid Cymbidium hybrid and the original diploid Cymbidium hybrid were exposed to high temperature（40 ℃/30 ℃,12 h light/day).The effects of stress on plant physiological and biochemical characteristics,including the chlorophyll content,the membrane damage degree,the osmosis-regulation substance content and the activities of protective enzymes,were analyzed to assess the difference of heat resistance between the diploid and tetraploid.The results showed that high temperature stress decreased the chlorophyll content of both seedlings,while tetraploid showed less decrease.The malondialdehyde (MDA) content was increased in both diploid and tetraploid plants,but diploid increased more.The O^-·₂ release rate was decreased in both diploid and tetraploid seedlings and decreased faster in diploid.The increasing ranges of leaf proline content,soluble sugar,soluble protein,and activities of catalase (CAT) and superoxide dismutase (SOD) were all higher in tetraploid,while decreasing ranges of POD activity was notable in diploids.Our results indicated that tetraploid was more powerful than diploid in heat resistance because tetraploid showed higher competence in cell osmosis-regulation,protein synthesization and stabilization,and reactive oxygen species (ROS) elimination.

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