孕穗抽穗期低温对水稻植株、产量性状及脯氨酸含量的影响

低温是东北稻区常见的气象灾害。此试验以北方主栽粳稻品种辽星1号和辽优5218为试材，采用盆栽试验，人工控温在孕穗期、抽穗开花期进行低温胁迫，处理后立即测定叶片脯氨酸含量，成熟后调查植株和产量性状的变化，探讨生殖生长关键期低温伤害机理及叶片脯氨酸含量的变化在低温逆境中的作用。结果表明：植株性状中，株高在抽穗开花期对低温更敏感；穗抽出度则在孕穗期更敏感，穗抽出度与单株实粒数及结实率呈显著或极显著正相关，可作为抗性鉴定指标应用。产量性状中，穗粒数、单株实粒数、千粒重指标在孕穗期对低温更敏感。低温胁迫下，叶片脯氨酸含量随温度的降低、处理时间的延长而迅速上升，辽星1号最大增加2.65倍，辽优5218增加7.66倍。孕穗期低温，辽优5218叶片脯氨酸含量与穗抽出度、单株实粒数及单株结实率呈显著负相关；抽穗开花期低温，两品种叶片脯氨酸含量与株高、单株实粒数及单株结实率均呈显著负相关，辽星1号脯氨酸含量还与单株秕粒数呈极显著正相关。脯氨酸含量的变化是低温伤害程度的直观反映，把它单独作为抗性评价指标会有失真的可能。

Effects of Low Temperature Stresses on the Characters of Plant , Yield and the Proline Contents in Rice Leaves at Booting and Heading Stages

Taking ‘ Liaoxing1 ’ and Liaoyou5218 at booting and heading stages as test materials, this paper studied the changes of the characters of plant and yield and its relationships with the proline contents of rice leaves under low temperature stresses in pot experiment in order to discuss the injury mechanism of low temperature on reproductive growth stages and the function of changes of proline content of leaves in stresses. The results showed that the plant height was more sensitive to low temperature at the heading stage among characters of plant. Panicle exsertion was more sensitive to low temperature at booting stage, and it had significant positive correlations with the full-filled grains and the seed setting rate, it might be used as evaluation index in study of stress resistance. Indexes of grains per spike, full-filled grains per hill and 1000-grain weight were more sensitive to low temperature at booting stage among characters of yield. The lower and longer the temperature stress, the higher the proline contents in rice leaves. The highest proline value added of ‘ Liaoxing1 ’ was 2.65 times higher than that of the control, and that of ‘ Liaoyou5218 ’ was 7.66 times. At booting stage, the proline contents of ‘ Liaoyou5218 ’ had significant negative correlations with the panicle exsertion, the full-filled grains per hill and the seed setting rate. At the heading stage, the proline contents of ‘ Liaoxing1 ’ and ‘ Liaoyou5218 ’ were significant negative to the plant height, the full-filled grains per hill and the seed setting rate. And there was a significant positive correlation between the praline content and the unfulfilled grains per hill of ‘ Liaoxing1 ’ . The changes of the proline contents were objective appearances of low temperature stresses, and it would lead to an inaccurate result in study of stress resistance when it was used as the only evaluation index.