关键词: 紫花苜蓿, 高温胁迫, 腐胺, 精胺, 亚精胺

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