为了明确外源激素诱导水稻抗旱性的效果及其生理机制。以中嘉早17为材料,分析外源激素在淹水灌溉、干湿交替灌溉和干旱灌溉方式下叶绿素荧光参数的差异及其对产量与产量构成的影响。结果表明,干旱灌溉显著降低了叶片光系统Ⅱ(PSⅡ)最大光化学量子产量、实际光量子效率、非光化学猝灭值、有效穗数、每穗粒数、结实率,孕穗期比分蘖期更为敏感,表现为相同胁迫时间下最大光化学量子产量、每穗粒数、单株穗数等下降更显著。赤霉素(gibberellin, GA3)处理后降低了PSⅡ最大光化学量子产量、非光化学猝灭和光化学猝灭系数,导致有效穗数减少、千粒重和结实率降低。脱落酸(abscisic acid, ABA)处理能缓解孕穗期干旱胁迫,减轻水稻叶片的光抑制程度,提高叶绿素荧光参数,增强抗旱能力。综合来看,以分蘖期淹水条件下结合IBA处理产量最高,比对照增产7.4%,这可能与淹水条件下吲哚丁酸(indolebutyric acid, IBA)处理能提高光合效率有关。

To clarify the effects of exogenous hormones on rice drought stress and its physiological mechanism. Using cultivar rice variety Zhongjiazao 17 as the material, the differences in chlorophyll fluorescence characteristics and the relationship of the yield and yield components were analyzed under the flood irrigation, dry-wet alternate irrigation, and drought irrigation. The results showed that drought irrigation significantly reduced the maximal photochemical quantum yield of PSⅡ, actual photon quantum efficiency, non-photochemical quenching, effective panicles, grain number per panicle, and seed setting rate. Compared with tillering stage, rice at booting stage was more sensitive to drought stress and the maximum photosynthetic quantum yield, number of grains per panicle, and panicles per plant decreased more significantly under the same stress time period. After GA3 treatment, the maximum photochemical quantum yield, non-photochemical quenching and photochemical quenching coefficient of PSII were reduced, which resulted in the reduction of effective panicles, 1 000-grain weight and seed setting rate. ABA treatment can relieve the drought stress at booting stage, reduce the degree of photoinhibition in rice leaves, increase the chlorophyll fluorescence parameters and enhance drought resistance. Taken together, IBA treatment under flooding conditions at the tiller stage yielded the highest yield, which increased by 7.4% compared to that of the control. This is related to the increase of photosynthetic efficiency by IBA treatment.