不同生育期遮光对水稻生长发育和产量形成的影响

研究了不同生育期遮光45%(水稻生长的前期、中1期、中2期、后期)对水稻形态发育、光合产物积累、稻株养分含量、产量构成等的影响,并重点研究了植株对N、P、K养分的吸收规律。结果表明,各期遮光后均使干物质积累速率降低,植株N、P、K养分吸收量减少,对产量有不同程度的影响,但植株体内N、P、K养分含量上升。前期遮光主要使分蘖数急剧下降,有效穗数减少,叶面积系数下降,产量下降11.56%,但株高增加;中1期遮光后对水稻生长影响不大,产量仅降低5.46%;中2期遮光主要使每穗粒数和千粒重下降,对产量影响较大,降低幅度达30.80%;后期遮光主要影响结实粒和千粒重,其产量最低,降低55.40%.文中还对弱光照条件下的生育期安排和施肥决策提出了建议.

Effect of shading on growth, development and yield formation of rice

Field experiments under 45% shading at different stages(early, middle 1, middle 2 and later stages) of rice growth show that regardless of different stages, shading decreased the accumulation rate of dry matter and the uptake of nutrients, but increased the nutrient content in rice plant, and affected its yield in varying degrees. Shading at early growth stage mainly decreased tiller number, effective panicle number and leaf area index, and reduced yield by 11.56%, but increased plant height. At middle 1 stage, shading showed no significant influence on rice growth, and the yield was reduced by only 5.46%. At middle 2 stage, shading mainly decreased grains per panicle and 1000 grain weight, and the yield was reduced markedly by 30.80%. At later stage, shading decreased the percentage of filled grains and 1000 grain weight, and the yield was the lowest, reduced by 55.40%. Suggestions on the way of regulating sowing and transplanting dates and making fertilization decision under low light intensity also put forward in this paper.