不同密度条件下小麦光合能力的研究

研究了两个品种不同叶位的光合能力。冬前叶的光合能力低于春生叶,春生叶以倒二叶的光合强度最高。旗叶的光合能力只是在灌浆期后才高于倒二叶。基本苗4～8万/亩的群体光合强度至越冬期能赶上或超过基本苗多的(16万/亩)对照处理,单株光合强度始終高于基本苗多的处理;单蘖的光合强度开始低于对照,至越冬期高于对照。春季控制分蘖数在40～60万/亩,可有利于单茎和群体光合能力的提高。盆栽群体条件下的光补偿点和光飽和点都高于单叶:光补偿点在3000～5000Lux,光飽和点則随每盆植株密度的增加而增加。控制春季分蘖,改善了群体內光照条件,促进了单茎健壯生长,在小麦生产中有利于粒多、粒重的提高。

STUDIES ON THE PHOTOSYNTHESIS ABILITY IN WHEAT UNDER THE CONDITIONS OF VARIANT DENSITY

The photosynthesis ability of leaves was studied in two varietiesof winter wheat. The rate of photosynthesis of spring leaves washigher than that of pre-winter leaves. It was raised to maximum insecond top leaves. The rate of photosynthesis of flag leaves was higherthan that of the second top leaves only after grain filling. The rate of photosynthesis in population of 40,000-80,000 basicseedlings/mu could be similar to or over that in 160.000/mu (CK) beforewinter. The rate of single tiller photosynthesis was lower than that incontrol at first and higher before winter. When the number of tillers of 400,000-600,000/mu in spring remained,it was favorable to increase the rate of photosynthesis of the single plantand population. The light compensation and saturation point of wheatpopulation in pot was higher than that of the single leaf; the lightcompensation point was 3,000-5,000 Lux, the light saturation Pointwas increased with the increase of density. Controlling spring tillerincreased light intense within population and promoted sturdily growthof the stem. It was favorable to increase the quantity and weight ofgrain in wheat production.