中文摘要：

采用盆栽试验,以常规灌溉为对照（CK）,研究了水稻在分蘖期轻度旱涝交替胁迫（T-LD）和重度旱涝交替胁迫（T-HD）前、后及复水后各个生育期的部分生理指标变化,以探讨旱涝交替胁迫对水稻生长影响的机理。结果表明,T-LD处理的水稻叶片硝酸还原酶（NR）活性显著高于T-HD处理和CK;与CK相比,旱涝交替胁迫处理显著降低了水稻叶片中丙二醛（MDA）的质量摩尔浓度和谷氨酰胺合成酶（GS）活性,显著增加了水稻叶片中叶绿素总量;复水后（黄熟期）GS活性均明显提高并高于CK。说明分蘖期旱涝交替胁迫可以增强水稻叶片的生理活性,延缓叶片衰老,不会降低水稻后期的耐淹能力。

英文摘要：

This paper investigated the impact of alternating waterlogging and drought during the tillering stage on physiological traits of rice using pot experiments. We considered both slight waterlogging-drought alternation （T- LD） and severe waterlogging-drought alternation （T-HD）. Main physiological traits were measured before, during and after occurrence of these stresses. The results showed that the activity of nitrate reductase in the leaves under T-LD was higher than those under T-HD and CK （conventional flooding）. In comparison with those under CK, the concentration of malondialdehyde and the activity of glutamine synthetase （GS） under T-LD and T-HD de- creased significantly, while the concentration of chlorophyll increased. At ripening stage after re-watering, the ac- tivity of GS increased considerably and was higher than that under the CK, indicating that a moderate waterlog- ging-drought alternation during tillering stage can enhance physiological activity of the rice and delayed senes- cence without scarifying tolerance of the rice to flooding.