抽穗后干旱复水对双季杂交晚稻产量形成和叶片δ13^C及内源激素水平的影响

Effects of Rewatering after Drought at Heading on Yield, δ^(13)C and Contents of Endogenous Hormone of Leaf in Double-Season Late Hybrid Rice

为探明生育后期干旱复水对双季杂交晚稻不同产量潜力品种产量的影响及其形成的生理机制,选择超级稻品种五丰优T025和对照品种金优207,于抽穗后进行干旱8d复水处理,分析了2个品种结实和产量、干旱前后倒二叶稳定碳同位素组成(δ13C)及内源激素含量的差异性。结果表明,干旱复水处理下2个品种水稻的结实率、千粒重及单株产量较对照(保持水层)表现出不同程度下降。其中,结实率五丰优T025和金优207分别下降12.07%和7.67%,千粒重下降5.23%和9.09%,单株产量下降13.54%和27.14%,差异均达显著或极显著水平,未发现产量补偿效应。抽穗后干旱处理下倒二叶δ13C值,五丰优T025大幅上升,复水后呈现出先下降,至第6天又开始上升的特点,金优207则大幅下降,复水后呈现先上升后下降再上升的特点,五丰优T025较金优207干旱复水处理与对照之间的差距更大。总体上,对照条件下,抽穗至其后20d,随生育推进,2个品种倒二叶内源ABA和GA3含量呈上升而IAA含量则下降趋势,ZR表现出先上升再下降特点。干旱处理下2个品种表现为ABA含量上升,复水后呈先下降后上升特点,五丰优T025较金优207处理与对照之间差距更大;干旱复水处理条件下:2个品种IAA含量均下降,五丰优T025处理与对照间的差距明显小于金优207;五丰优T025 GA3含量表现出先上升后下降再上升,金优207表现出干旱处理结束日急剧下降至最低点,复水后缓慢上升特点;2个品种ZR含量呈现出先上升至最高值再下降特点,五丰优T025较金优207处理与对照之间差距更小。抽穗后干旱处理将启动稻株体内抗衰老机制,复水后将在一定程度一定时间内激活稻株体内生长促进因子并抑制生长抑制因子,但其效果十分有限。

In this study, super rice variety WufengyouT025 and the control variety Jinyou207 were selected to drought 8 days after heading, then rewatered to explore effect of yield and its formative physiological mechanism under the treatment of rewatering after drought during the late growth stage for the different yield potential double-season late hybrid rice varieties. The differences of the seed setting, yield, carbon isotopic compositions （δ13^C） and endogenous hormone in the reciprocal second leaf during fore-and-aft drought of the two varieties were also analyzed. Results showed as follows： Compared to the CK （keeping water） , seed-setting rate, 1000-grain weight and yield per plant of the two rice varieties presented diverse decline under the treatment of rewatering after drought stress. Among them, thereinto, seed setting rate of WufengyouT025 and Jinyou207 decreased by 12. 07 % and 7.67 % , 1000-grain weight 5.23 % and 9. 09 % , yield per plant 13.54 % and 27.14 % , respectively. All the differences were obselwed significantly and there was a lack of yield compensatory effect under the treatment of rewatering after 8-d drought at heading. Carbon isotopic compositions （δ13^C） in the reciprocal second leaf under the treatment of drought at heading of WufengyouT025 greatly increased, decreased at first then began increasing at the 6d after rewatering, while that of Jinyou207 under the treatment of drought decreased greatly, increased at first then decreased, then increased, the distance between the treatment and the control of WufengyouT025 were higher than that of Jinyou207. Generally, under the condition of the CK from heading to 20 days, endogenous hormone in the reciprocal second leaf of the two varieties of ABA and GA3increased, IAA declined along with the growth course, while ZR increased at first then decreased. Under the treatment of drought of the two varieties, ABA increased, then decreased after rewatering, then increased, the distance between the treatment and the control of WufengyouT025 were higher than that of Jinyou207. Under the condition of the treatment of rewatering after drought, IAA of the two varieties all decreased, and the distance between the treatment and the control of WufengyouT025 was lower than that of JJinyou207, GA3 of WufengyouT025 increased at first, then decreased after rewatering, then increased, while that of Jinyou207 decreased sharply and reached bottom at the end of the treatment of drought, and increased slowly after rewatering, ZR of the two varieties all increased and reached culmination, then decreased after rewatering, the distance between the treatment and the control of WufengyouT025 were lower than that of Jinyou207. The treatment of the drought at heading would promote the senescence resistant mechanism in the rice plant, and rewatering would activate the growth promoted factors and inhibited the growth restrained factors, but the effects were quite limited.