Abstract: Physiological responses of weedy rice to cold  stress  were investigated with weedy rice WR0345 and WR0326 as materials and Lijiangxintuanheigu as   control. The fluctuations of physiological indexes of leaves and roots of  weedy rice and cultivated rice at 5 ℃ in  an artificial climate chamber were investigated. The physiological indexes of leaves of weedy rice and cultivated rice followed a similar trend except the contents of chlorophyll and carotenoids under cold stress. The change of thiobarbituric acid reactive substances(TBARS) and proline contents of weedy rice differed from cultivated rice, but it is otherwise for the change of electrolyte leakage and soluble sugar content   in roots. Photosynthetic system   in weedy rice WR0345 and Lijiangxintuanheigu  was less damaged under  chilling stress. Due to less  injury and membrane lipid peroxidation, the cell membrane of weedy rice WR03 45 remained intact. The  soluble sugar and proline contents of   WR0345 were higher than those of   Lijiangxintuanheigu  under chilling stress. It indicated that weedy rice WR0345  was less injured under  cold stress because of   higher cold tolerance at the seedling stage .

Key words: cold stress, weedy rice, seedling stage, physiological response

摘要： 以杂草稻WR0345和WR0326为研究材料，以栽培稻丽江新团黑谷为对照，采用人工气候箱培养，研究了低温胁迫（5 ℃）对杂草稻幼苗期叶片和根系生理指标的影响。结果表明，除叶绿素和类胡萝卜素含量外，杂草稻叶片各生理指标的变化规律与对照相似; 杂草稻根系硫代巴比妥酸反应产物（TBARS）和脯氨酸的变化规律与对照不同，外渗电导率和可溶性糖含量的变化规律与对照相似。低温对WR0345和丽江新团黑谷的光合系统损伤较小；低温胁迫后，WR0345细胞膜系统保持完整，膜脂过氧化程度小于其他材料；WR0345可溶性糖含量和脯氨酸含量均高于对照品种。5 ℃低温对杂草稻WR0345伤害较小，表明WR0345具有较强的苗期耐冷性。

关键词: 低温胁迫, 杂草稻, 苗期, 生理响应