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为阐明低温胁迫下激素含量对冬油菜枯叶期的调控和对抗寒性的响应,为冬油菜抗寒性研究提供依据,以8份不同抗寒等级的白菜型和甘蓝型冬油菜为材料,利用盆栽试验,待幼苗长至5~6片真叶时在人工气候箱中进行低温处理(25℃、10℃、2℃、?5℃),分析低温胁迫后冬油菜内源ABA、GA含量和叶绿素的变化。回归分析表明温度与ABA含量存在显著的负相关,回归方程符合y=?ax+b,随着温度的降低,内源ABA含量呈先缓慢(10℃)后迅速上升(2℃、?5℃)的趋势,且温度处理间、温度与品种互作间差异极显著;由于激素间的拮抗作用GA含量变化则恰好相反。当在0℃以上低温时,品种间ABA含量无明显差异,当温度降到?5℃,白菜型冬油菜ABA含量明显高于甘蓝型,抗寒性强的品种高于抗寒性弱的品种。ABA含量的升高导致叶绿素含量的变化,随着温度降低,叶绿素含量呈先降低后增加的趋势,但总体呈下降趋势,且白菜型冬油菜和甘蓝型冬油菜之间存在不同的响应机制,这种作用使白菜型冬油菜叶绿素含量低于甘蓝型冬油菜,导致白菜型冬油菜枯叶期提前,提早进入越冬期,增加了对低温冻害的御性和避性。因此,随着温度的降低冬油菜叶片ABA含量上升,叶绿素降解,白菜型冬油菜更早进入枯叶期,枯叶期较早和降温后ABA含量高是白菜型冬油菜抗寒性较强的主要原因。
In order to elucidate the regulation of winter rape during the dry season and the response to cold stress, the objective of the study was to provide a basis for the research on the cold resistance of winter rape. Eight cabbage and Brassica napus cultivars with different cold tolerance were used as materials, Pot experiments were conducted to determine the contents of ABA and GA in winter rapeseeds after low temperature stress when the seedlings grew to 5 ~ 6 true leaves in the artificial climate chamber at low temperature (25 ℃, 10 ℃, 2 ℃,? 5 ℃) And chlorophyll changes. Regression analysis showed that there was a significant negative correlation between temperature and ABA content, and the regression equation was in accordance with y =? Ax + b. As the temperature decreased, the content of endogenous ABA increased rapidly (10 ℃) ), And there was a significant difference between the temperature treatments and the variety intercropping. The antagonism of hormones had the opposite effect on the GA content. When the temperature was above 0 ℃, there was no significant difference in ABA content between cultivars. When the temperature dropped to -5 ℃, the content of ABA in cabbage-type winter rape was significantly higher than that in cabbage-type, . The content of chlorophyll increased with the increase of ABA content. With the decrease of temperature, the content of chlorophyll decreased first and then increased, but decreased in general. There were different response mechanisms between Brassica campestris and Brassica napus, This effect makes cabbage-type winter rape chlorophyll content is lower than cabbage-type winter rape, leading to early cabbage-type rapeseed early stage, early into winter, increased the low-temperature frost damage of the impediment and avoidance. Therefore, with the decrease of temperature, ABA content of rapeseed leaves increased, chlorophyll degradation, cabbage-type rapeseed earlier entered the dead leaves, early and late leaves of ABA after high temperature, cabbage-type winter rape cold resistance is strong main reason.