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作 者 ：徐胜,何兴元,陈玮,李建龙,张剑岷

期 刊 ：生态学报 2008年 28卷 1期 页码：162~171

关键词：高羊茅；多年生黑麦草；活性氧；抗氧化剂；热锻炼；叶绿体超微结构；

Keywords:Festuca arundinacea, Lolium perenne, reactive oxygen species, antioxidant, heat acclimation, chloroplast ultrastructure,

摘 要 ：夏季高温胁迫已成为限制冷季型草坪草生长和发育的一个主要问题。以两种耐热性不同的冷季型草坪草高羊茅和多年生黑麦草（前者较耐热）为材料，经过3d 30℃的热锻炼预处理后，分别在38、 42、46℃的高温下处理14h。在这些高温条件下，研究了经过热锻炼预处理的高羊茅和多年生黑麦草叶片膜脂过氧化、抗氧化剂含量以及叶绿体超微结构的变化。结果表明：(1) 热锻炼提高了高羊茅和多年生黑麦草的耐热性，显著缓减了高温条件下两种草坪草叶片膜脂过氧化程度的加剧，降低了叶片过氧化氢（H₂O₂）和超氧阴离子（O•-2）的产生速率。（2）高温条件下，热锻炼使高羊茅和多年生黑麦草叶片中抗氧化剂抗坏血酸（AsA）和谷胱甘肽（GSH）的含量下降程度有所缓减。（3）热锻炼减轻了高温胁迫对高羊茅和多年生黑麦草叶片叶绿体超微结构的损伤。这些结果说明热锻炼能够减轻高温对草坪草叶绿体的伤害可能与其在高温胁迫下和对照相比具有较高的抗氧化剂含量有关，这也可能是冷季型草坪草对高温的适应机制之一。

Abstract:High temperature stress is one of the major factors limiting the growth and development of cool-season grasses during hot summer in warm climatic regions. Changes in the membrane lipid peroxidation, antioxidant content, as well as ultrastructure of chloroplasts were investigated in leaves of two cool-season turfgrass species, Festuca arundinacea (moderately heat sensitive) and Lolium perenne (heat sensitive), exposed to three temperature levels (38, 42, 46℃) for 14 h respectively with a heat acclimation pretreatment at 30℃ for 3 d in a growth chamber. Relative water content (RWC), cell membrane thermostability, malondialdehyde (MDA) content, accumulation of hydrogen peroxide (H2O2) and production rate of superoxide (O•-2), ascorbate (AsA) and glutathione (GSH) contents were measured in leaves of the two turfgrass species. The results showed as follows: (1) Significant accumulation of H2O2 and high production rate of O•-2 were observed in leaves of the two turfgrass species at all tested temperature levels regardless of whether heat-acclimated or not, but the degree of accumulation and the production rate in heat-acclimated turfgrass were lower than in non heat-acclimated turfgrass. (2) The changes in contents of AsA and GSH in the two turfgrass species showed significantly the trend of decrease with increase of high temperature. The contents of AsA and GSH in leaves of heat-acclimated turfgrass were higher than in non heat-acclimated turfgrass at same temperature level. (3) The degree of damage in chloroplasts increased with increasing of temperature. Ultrastructure of chloroplasts in heat-acclimated leaves was damaged less by high temperature stress than those plants without heat acclimation. The findings suggested that it might be helpful to protect the integrality of chloroplasts from the impact of high temperature stress by the heat acclimation pretreatment that induced lower membrane lipid peroxidation, higher AsA and GSH contents in leaves of two turfgrass species, which might be also one of the mechanisms for adaptation of cool-season turfgrass to heat stress.

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