持续土壤水分胁迫对水稻生育与产量构成的影响

EFFECTS OF SUSTAINED SOIL WATER STRESS ON GROWTH, DEVELOPMENT AND YIELD COMPONENTS OF TWO RICE CULTIVARS

在蒸渗仪中用张力计监测并严格控制土壤水势，研究不同程度的持续土壤水分胁迫对两个中熟水稻品种（组合）汕优６３和盐粳２号的生长发育和产量构成的影响。结果表明：在持续土壤水分胁迫下，①两品种生育前期叶面积的形成均受到抑制，且受抑程度与水分胁迫程度呈正相关，叶面积峰值出现较浅水层处理迟，生育后期叶面积下降较为迟缓；②两品种生育前期的分蘖发生受到抑制，在生育后期除了汕优６３在较轻程度的水分胁迫下分蘖数略高于浅水层处理外，两品种在其余各胁迫处理下分蘖的变化基本上不受胁迫处理影响；③随着胁迫程度的增加，两品种的株高降低，生育期延迟；④两品种产量下降的幅度与胁迫程度呈正相关，当土水势保持在－０．０２５～－０．０４５ＭＰａ时，汕优６３的减产幅度较盐粳２号大，而当土水势降到－０．０７０～－０．０７５ＭＰａ时，盐粳２号的减产幅度大于汕优６３，主要由于穗颖花数的减少。

The effects of sustained soil water stress on growth, development and yield components were studied with two rice cultivars Yanjing No.2 and Shanyou No.63 at four different soil water potentials (shallow water layer(CK), -0 025￣-0 030 MPa, -0 040￣-0 045 MPa and -0 070￣-0 075 MPa) during 1992￣1993. Results obtained were as follows: In stress treatments of two cultivars, formation of leaf area and tiller was depressed at the early stage of growing period, the arrival of maxmium leaf area per plant was delayed and decrement of leaf area at the late stage of growing period was slow. Except for the number of tiller per plant in Shanyou No.63 while soil water potential kept between -0 025 MPa and -0 030 MPa being a little more than control, dynamics of tiller number during late stage were less influnced by stress. Plant height was decreased and growing period was extended increasly with the increment of the degree of stress. Loss of grain yield of both cutivars was found to be positively related to the degree of stress, largely owing to the decrement of spikelet number per panicle.