Abstract: Using 6 mid-maturing lowland and upland rice varieties as materials, the relationship between free proline accumulation and the drought resistance in rice plants under different status of soil moisture was studied. The results showed that: 1) the free proline accumulation in the leaves of drought-resistant varieties began earlier and the duration was longer under the treatments of low soil moisture, compared to the less drought-resistant ones, the leaf water potential threshold of obivious proline accumulation was -0. 62 to -0.66 MPa for the former and -0.78 to -0.82 MPa for the latter; 2) the relative proline content (the treatments/the control×100% ) after the treatment for 10 days very significantly correlated with the drought-resistant coefficient of the varieties at -0. 04 MPa of soil water potential (r=0. 9712); and 3) the relative proline content after the treatment for 30 and 40 days had a significant negative correlation with the yield reduction percentage at -0.04 and -0.06 MPa of soil water potential (r=-0.9342 and -0.9581, respectively). It was suggested that the physiological character of early accumulation and long duration of free proline under the condition of low soil moisture be regarded as an index for evaluating the drought resistance of rice varieties.

Key words: drought-resistance, proline, soil moisture

摘要： 以6个中熟水、陆稻品种为材料，研究了在不同土壤水分状况下水稻叶片中游离脯氨酸的累积及其与抗旱性的关系。在低土壤水分处理下，抗旱性水稻品种叶片中游离脯氨酸累积开始较早，持续时间长，抗旱性较差的品种则开始较迟，持续时间短；脯氨酸开始累积的叶水势阈值，抗旱性品种为－0.62～－0.66 MPa，抗旱性较差的品种为－0.70～－0.82 MPa；土壤水势为－0.04 MPa时，处理10 d后叶片的相对脯氨酸含量（处理／对照×100%）与品种的抗旱系数呈极显著正相关（r＝－0.9712）；保持土壤水势为－0.04 MPa和－0.06 MPa，处理后30 d和40 d叶片的相对脯氨酸含量与减产率呈极显著的负相关（r＝－0.9342、－0.9581）。建议把在低土壤水分条件下脯氨酸累积较早、持续时间长这一生理特性作为评价水稻品种抗旱性的一个指标。

关键词: 土壤水分, 脯氨酸, 抗旱性