不同时期三个小麦主栽品种叶片光合作用的研究

Studies on Leaf Photosynthesis of Three Leading Wheat Cultivars Released in Different Period

不同时期三个小麦主栽品种不同层次叶片的最大光合速率均出现在盛花期以前。在灌浆期间,当前高产良种鲁麦14的光合速率下降速度较慢,比早期品种碧蚂1号和济南2号有一个较长的高光合持续期,这种差异在下部叶片表现得更为明显一些,尤其是倒3叶。从不同叶位叶片看,挑旗期参试品种均以倒2叶光合速率最高;盛花期以后,旗叶则逐渐占明显的优势。本文用叶片光合速率与叶面积的乘积,即全叶同化速率为指标,可较全面地反映不同品种叶片同化能力的大小。鲁麦14在灌装期间全叶同化速率占一定优势。叶片比叶重是鉴定筛选高光合速率个体的简单可靠的间接指标。叶片气孔阻力对光合速率有一定负效应,而叶片蒸腾对光合速率则有一定正效应。盛花期以前,叶片光合主要受气孔因素制约,而在生育后期,非气孔因素亦有很重要的作用。对小麦高产育种,尤其是光合特性的改良问题进行了讨论。

The leaf photosynthefsis and relative characters were investigated in this paper with three leading wheat cultivars released in different period. The results showed that the photosynthetic rates for all three upper leaves of three examined cultivars reached maximum before full-bloom stage, and after that, declined gradually. During grain filling period, the photosynthetic rate of Lumail4 declined most slowly amomg all the three cultivars, therefore it had a longer high photosynthesis duration than Bima 1 and Jinan2, which was more significantly in lower leaves, especially the third leaves from the above. At the flag leaf expansion stage, the second leaves from the had the highest photosynthetic rate, but after full-bloom stage, the flag leaves gradually occupied adominant position, the Entire Leaf Assimilative Rate (ELAR) could depict more comprehensively the difference in leaf assimilative capacity, and the total ELAR for upper three leaves of Lumai 14 gained some dominance over Bima 1 and Jinan 2 during grain filling period. Specific Leaf Weight was a good index to identify and select superior plants with high photosynthetic rates. While leaf stomatal resistance had negative effects on photosynthesis, transpiration rate had positive effects. Before full-bloom stage, the stomatal factor was a main limitation for photosynthesis, but after that period, non - stomatat factor got more and more important. In order to developing high yielding cultivars by means of com - bining idel plant type and high photosynthetic rate, some questions were discussed.