旱涝交替胁迫对拔节期水稻生长和土壤氧化还原电位的影响

Response of Rice Growth and Soil Redox Potential to Alternate Drought and Waterlogging Stresses at the Jointing Stage

【目的】系统研究不同胁迫组合对水稻生长和土壤氧化还原状况的影响。【方法】通过盆栽试验,设置了2个旱涝交替胁迫处理(T1:轻旱-轻涝-轻旱,T2:重旱-轻涝-重旱)和1个对照处理(CK:常规灌溉),测定了拔节期水稻株高、干物质量、叶片叶绿素和土壤氧化还原电位值(Eh)。【结果】拔节期旱涝交替胁迫处理抑制水稻株高的生长,直至成熟期,T1和T2处理株高仍较CK显著降低了8.54%和13.16%(p<0.05);旱涝交替胁迫可以降低水稻叶片叶绿素量,但复水后旱涝交替胁迫处理的水稻叶片叶绿素量逐渐增加,到生育后期,T1和T2处理的水稻叶片中叶绿素量较CK显著增加了26.65%和34.41%(p<0.05);收获时,T1和T2处理根质量显著高于CK,T2处理总干质量显著低于T1处理和CK,T1和T2处理的水稻根冠比分别达到了CK的1.40倍和1.67倍(p<0.05);拔节期旱涝交替胁迫可以增加Eh,胁迫结束时,T1和T2处理的Eh分别达到了CK的3.31倍和3.23倍(p<0.05)。【结论】拔节期旱涝交替胁迫可以降低水稻株高,复水后可以延缓水稻叶片衰老,增加水稻根冠比以及可以改善水稻土的氧化还原状况,但T1和T2处理降低了水稻产量。

【Objective】In southern China rice is susceptible to alternate stresses of drought and waterlogging, and this study was to analyze the rice growth and soil redox potential under different drought-waterlogging stresses aimed to provide a guidance for soil water management and rice irrigation.【Method】The experiments were conducted in pots and we examined two treatments： light drought-light flood-light drought stress（T1）, and severe drought-light waterlogging-sever drought, with the conventional irrigation as control（CK）. For each treatment,we measured plant height, dry weight, chlorophyll content and soil redox potential（Eh）, from which we elucidated the mechanism underlying the effect of water stress on rice growth at jointing stage and the dynamic change of Eh.【Result】Alternate drought and waterlogging（ASDW） stresses inhibited plant growth up to maturity stage,and the plant height under T1 and T2 was significantly lower than that under CK, decreasing by 8.54% and13.16%（p〈0.05） respectively. ASDW reduced the chlorophyll content of the leaves, but after re-watering the chlorophyll content recovered gradually and at the late growth period, the leaf chlorophyll content under T1 and T2 increased by 26.65% and 34.41% compared to CK（p〈0.05）. At harvest, the root mass under T1 and T2 was significantly higher than that under CK, and the total dry weight under T2 was significantly lower than that under T1 and CK. The root-shoot ratio under T1 and T2 was 1.40 times and 1.67 times of the CK（p〈0.05） respectively. ASDW also increased soil Eh and after the cease of the stress, Eh under T1 and T2 were 3.31 times and 3.23 times of that under CK respectively（p〈0.05）.【Conclusion】ASDW at jointing stage reduced the plant height, delayed the senescence and increased the root shoot ratio. It improved the redox in soil after re-watering, but compared to CK, the actual yield under T1 and T2 decreased by 19.01% and 39.80% respectively.