花铃期遮光对棉花生长发育和冠层结构的影响

Effect of Shading on the Growth and Development and the Canopy Structure of Cotton in Flowering - boll Forming Stage

[目的]研究花铃期遮光对棉花生长发育和冠层结构的影响,为果棉间作棉花栽培技术的合理制定提供依据。[方法]以中棉所49号和新陆早36号为材料,在大田条件下,研究遮光条件下棉花生育进程、农艺性状、冠层结构和透光率的变化。[结果](1)花铃期遮光,单株结铃数、籽棉和皮棉产量随着光强的降低,降幅显著增大,收获株数和单铃重降幅较小,但对衣分无明显影响。(2)遮光30%和50%处理的盛花期提前;盛铃期至吐絮期,随着遮光时间的延长和光强的减弱明显推迟;(3)遮光对棉株的主茎真叶数和果枝台数无明显影响;遮光50%的茎粗明显减小;随着光强的降低,倒四叶宽度和叶面积指数显著减小,遮光50%处理的冠层开度、平均叶倾角和透光率显著高于自然光。[结论]降低光照,延缓营养生长向生殖生长的转移。棉花叶片通过增大平均叶倾角,增加透光率而减小叶面积指数,以获取更多的光能,提高光能的利用效率。新陆早36号具有较强的形态学调节适应能力。适当降低光强,中棉所49号的产量降幅较小,但光强过弱,降幅大于新陆早36号,对弱光的敏感性较强。

[Objective]The objective was to study the effect of low irradiance on growth and development and canopy structure of cotton,and to provide the basis of reasonable decision of cultural practice for fruit -cotton intercropping.[Method]Two upland cotton,Zhongmiansuo No.49 and Xinluzao No.36,were used to investigate growth and development phase,agricultural character,canopy structure and light transmittance in different irradiance in field condition.[Result](1) Shaded at the flowering period,decreasing amplitude of boll number per plant,seed cotton and lint yield significandy increased,but the number of harvest plant and mass per boll dropped a little,was and did not significandy affected the lint percentage with the reduction of light intensity;(2) Full blossoming stage advanced in shading 30%and shading 50%treatments.Full boll stage to boll opening stage significandy would be delayed with the extension of the shading time and the weakening of light intensity,and difference gradually increased between treatments.(3 ) There was no significant effect on the true leaf number of the main stem and fruit branch number in shading conditions;the width of the last - forth leaf and LAI would be significantly reduced with light intensity reducing,but stem diameter,DIFN,MTA and LT of shading 50%significantly were higher than those in natural light. [Conclusion]If the lighting time was reduced,the transfer of nutritional growth to reproductive growth would be delayed.Cotton leaf increased MTA to add LT and decreased LAI in order to get more light energy and to improve the use efficiency of light energy.Xinluzao No.36 had stronger morphological acclimatization adaptable to weak light.Reducing light intensity properly,the yield of Zhongmiansuo No.49 would be lowered less than Xinluzao No.36,but with weaker light,the result was contrary,performing the stronger sensitivity to weak light.