Abstract:

It is significant to study the heat tolerance of Medicago sativa due to the lack of high quality alfalfa cultivar which adapt to the high temperature in south area. Polyamines are closely related to the plant abiotic stress response. The Put, Spd and Spm contents of high fall dormancy cultivar ‘Sardi 10’, low fall dormancy cultivar ‘Algonguin’ and ‘Deqin’, which adjust the dry-hot valley climate, were determined for the relationship between polyamines and heat-tolerance under a 35℃/30℃ heat stress for 105 days. The results showed that the Put and Spm contents of all tested cultivars increased first and then decreased, and that of low fall dormancy cultivar was higher than others at the end of stress, whereas that of high fall dormancy cultivar started decline 21 days earlier than low fall dormancy cultivar. The Spd content of high fall dormancy cultivar increased, whereas that of low fall dormancy cultivar decreased continually, and the cumulative growth rates were 16.81% and -26.21%, respectively. However, the responses of Spd content in ‘Deqin’ cultivar categorized as low fall dormancy were similar to ‘Sardi 10’ cultivar categorized as high fall dormancy. It showed that the heat-resistance of ‘Deqin’ might be correlated with the high Spd content and low Put and Spm content, and it was also probably one of the reasons for being survival in the dry hot valley.

Key words: Alfalfa, Heat Stress, Put, Spm, Spd

摘要：

我国缺乏适宜在南方高温地区生长的优质紫花苜蓿(Medicago sativa)品种,研究紫花苜蓿耐热性具有重要意义。多胺与植物逆境胁迫响应密切相关。本试验以高秋眠级紫花苜蓿品种‘赛迪10’、低秋眠级紫花苜蓿品种‘阿尔冈金’和适应云南干热河谷的‘德钦’紫花苜蓿为研究材料,研究腐胺、亚精胺、精胺含量在胁迫温度35℃/30℃(白天/夜晚)条件下105天内的变化,分析多胺与紫花苜蓿耐热性之间的关系。结果表明,紫花苜蓿的腐胺和精胺含量在高温胁迫下先升后降,期间低秋眠级品种的腐胺和精胺含量较高,高秋眠级品种的精胺含量开始下降的时间比低秋眠级品种早大约21天;紫花苜蓿的亚精胺含量在高温胁迫下变化有所不同,高秋眠级品种的亚精胺含量会有所增加,而低秋眠级品种则显著下降,累计增长率分别为16.81%和-26.21%。‘德钦’紫花苜蓿与‘阿尔冈金’同为低秋眠级紫花苜蓿品种,但在高温胁迫下其多胺含量的变化却与高秋眠级品种‘赛迪10’一致。高温胁迫下德钦紫花苜蓿的耐热性可能与较高的亚精胺含量和较低的腐胺和精胺含量有关,是其能在干热河谷生存的原因之一。

关键词: 紫花苜蓿, 高温胁迫, 腐胺, 精胺, 亚精胺