水稻群体冠层结构与光合特性对产量形成作用的研究

 本文研究了水稻群体冠层结构与光合特性对不同类型品种产量形成的作用，结果表明：冠层倒4叶至倒1叶叶长与每穗总粒数呈极显著正相关，冠层各叶叶长与结实率、千粒重及单株产量的关系因品种类型不同而有较大差异；抽穗后冠层叶片的比叶重和叶绿素含量与杂交籼稻和中籼品种的结实率、产量呈显著或极显著正相关，与中粳品种的结实率、产量相关不显著；增加抽穗至成熟期叶片的净同化率，对促进杂交籼稻汕优63籽粒生长的作用较大，对中粳品种盐粳2号的作用较小；抽穗期顶3叶叶面积占冠层最大叶面积之比是衡量群体发展合理与否的一个指标，适当提高这个比值，有利于增加抽穗后干物质的积累和提高产量。

EFFECTS OF THE STRUCTURE AND PHOTOSYNTHETIC CHARACTERS OF THE CANOPY ON THE YIELD FORMATION IN RICE PLANTS

The effects of the structure and photosynthetic characters of rice canopy on the yield formation were studied with the major mid-ripe cultivars in Jiangsu as materials in this experiment. The results were as follows:1. The length of each leaf of the canopy had significant positive correlations with the spikelets per panicle except the 5th leaf from the top. The correlation between the length of canopy leaves and the seedset percentage, grain weight and the yield per tiller was greatly varied in cultivars: For Indica hybrid such as Shangyou 63 the length of the 5th, 4th and 3rd leaves from the top had significant negative correlations with the seedset percentage and the yield per tiller; For mid-ripe Japonica cultivars such as Yanjing 2, the length of each leaf of the canopy had no significant correlations with the seedset percentage and grain weight, and the length of each leaf from the 4th to lst leaves counted from the top had significant positive correlations with the yield per tiller.2.The ratio of the leaf area index (LAI) of the 3 leaves from the top to the maximum LAI of canopy leaves at heading stage could be regarded as an index evaluating whether a population develops rationally or not.The dry matter accumulation from heading to harvest and the grain yield would increase if the ratio could be raised properly.3. The correlations of the specific leaf weight and chlorophyll content with the seedset percentage (r_1), grain weight (r_2) and the grain yield (r_3) were significant at 0.05 level or 0.01 level for the Indica hybrid; For rnidripe Indica varieties of IR24 et al., r_2 was not significant, but r_1 and r_3 were significant at 0.05 level; For midripe Japonica ones, such as Yanjing 2, r_1, r_2 and r_3 were not significant at 0.05 level.4. Increasing the net assimilation rate of canopy leaves had greater effects on the grain growth of Shangyou 63 than on that of Yanjing 2.