干旱胁迫对水稻生育性状与生理指标的影响

为了明确水稻不同生育阶段干旱胁迫对生育性状及生理指标的影响,以‘农大3号’（生育期145天）品种为试验材料,利用盆栽的形式,人工控制土壤水势（-75 kPa）,分别在水稻不同生育阶段进行了干旱胁迫对水稻生育和生理指标影响的试验研究.结果表明,分蘖期干旱单穴有效穗数减少6.05～9.52个,干旱越早影响越大.无论任何时期干旱胁迫,处理过后均可以导致干物重下降,成熟期下降幅度为11.20～25.94g/穴,孕穗期＞分蘖期＞出穗后各时期.叶面积指数的下降则是体现在干旱过后的下一阶段上,随着CK区基部叶片的衰老与黄化,各处理的叶面积指数逐步与CK接近,干旱越早,生育后期差异就越小.干旱对功能叶片（顶部3叶）长度的影响主要体现在分蘖后期、孕穗前期和孕穗中期,这3个阶段干旱,会明显导致顶部3片功能叶片变短.干旱对灌浆期剑叶和倒2叶的光合速率的影响主要体现在分蘖期和孕穗期,孕穗期＞分蘖期＞出穗期、灌浆期,剑叶光合速率降低幅度为3.25％～26.50％;倒2叶与剑叶的趋势一致,比CK下降3.93％～39.66％,下降幅度大于剑叶,乳熟期、蜡熟期干旱,测定时尚未进行干旱处理,两片叶的光合速率略高于CK.无论任何时期干旱胁迫,干旱过后都会导致叶绿素含量（SPAD）上升.水稻不同生育阶段干旱胁迫,均能导致单穴有效穗数下降、生物产量降低、功能叶片变短、LAI降低、光合速率下降,最终导致产量下降3.57％～50.79％.

Effect of Water Stress of Soil on Growing Characteristics and Physiological Index of Rice (Oryza sativa)

In order to explore the influence of water stress on the growing characteristics and physiological index of rice at different growing stage, using ＇Nongda 3＇ variety （145 days） as a material, by means of pot cultivation and manual rigorously controlling soil potential （-75 kPa） with tension-meter, the effects of soil water stress on the growing and physiological index of rice were studied. The results indicated that, when the soil drought stress during the tillering period, the efficacious panicles reduced 6.05-9.52 panicles each cluster, and the drought stress occurred earliest the influence were more obviously then others. Regardless of any period drought stress occurring, the dry material weight decreased after drought stress, and it dropped 11.20-25.94 g each cluster untill maturing period, and the effects of sequence were： booting stages 〉 tillering period 〉 stages after heading. As to leaf area index the decline appeared at the stage after drought stress, and accompanied by leaf aging and yellowing of contrast plot, the leaf area index gradually recovered to the normal,and drought stress occurred the earliest the difference were the smallest. If the drought occurred at tillering later stage, booting earlier stage and mid-term, the functional leaves （top 3 leaves） would be shorted. Drought stress affected the photosynthetic rate of flag and second leaf count backwards mainly at tillering and booting stages, i.e. booting stages 〉 tillering stages 〉 period after heading, and flag leaves decreased 3.25%-26.50%. The tendency of second leaf count backwards were the same to flag leaves, and photosynthetic rate gone or came down 3.93%-39.66% compared with CK, and the falling range greater than flag leaves. And the photosynthetic rate of two functional leaves were a little more than leaves of CK, when drought stress occurred at milk-ripe stage and stage of wax ripeness, because the drought dress not yet processed during the period of determination. No matter any time the drought stress occurred, the chlorophyll content （SPAD） would be increased. And the drought stress occurring at different growing stage of rice would result in the number of productive panicles, biological yield, leaf area index, photosynthetic rate decreased and functional leaves shorted, it finally resulted in the yield dropped to 3.57%-50.79%.