Studys On Canopy Photosynthesis Characteristic Of Cotton With Different Leaf-type

The article studies on population light distribution and canopy photosynthesis of different leaf shape cottons,okra-leaf type,narrow-leaf type,normal-leaf type.and studies on ratio of light permeance,leaf area index,etc of normal-leaf cotton by cut leaf ,in order to discover the influence to canopy photosynthesis by these factors,and search the best cotton plant structure using light fully in middle and lower layer.Follows is the result of this article:1. The difference of leaf area index,ratio of light permeance,ratio of light extinction isobvious (p<0.05), the contribution to colony is varied from top to lower layer in different leaf type cotton. The period of the max Contribution of middle and lower layer is different, the max contribution presents in full-bolling stage in Okra-leaf; full-flowering in narrow-leaf and boll-opening in normal-leaf. The precentage of contribution varieties obviously in different layer of these leaves. The averge contribution of middle and lower layer is 30% higher in okra-leaf; 27.3% in narrow-leaf ; In normal-leaf, the percentage of contribution of different layer is 3:2:12. High yield is related to period of every layer with max photosynthesis.the max photosynthesis of top layer in okra-leaf type is appeared 17 days earlier than middle and lower layer in okra leaf, the middle layer canopy photosynthesis almost keep higher from florescence to belling period. In narrow leaf cotton, the max photosynthesis is appeared 20 days latter in top layer than middle layer and lower layer, rising quickly in prophase and declining quickly latter. In Xinluzao33 and Xinluzao19, the max photosynthesis is appeared in every layer almost an the same time in normal leaf type, rising slowly .3. With ratio of light permeated enhanced and available light radiation increasing, canopy photosynthesis in middle and lower layer is rising, number of bell also increasing, weight of every bell increasing, ratio of bell falls reducing, number of mature bells increasing before frost period and percentage of bells weight to all dry weight. In okra-leaf type ,the percentage of bells weight to all dry weight is 5.89% higher than normal-leaf type.4. The type of 1/4-leaf-cut cotton is similar to okra-leaf type cotton, the whole ratio of light extinction is 1.025±0.075,this type plant represent advantage than normal-leaf type in evidence, the yield of seed and lint is 631.47±61.238 kg.hm^-2and 260.05±31.40 kg.hm^-2 higher than normal-leaf type. The type of 3/4-cut-leaf cotton is similar to narrow-leaf type contton, available light radiation dissipated serious, canopy photosynthesis rising quickly in prophase and declining quickly latter ,all grown period is 11days shorten,mainly in flower-bell period.5. Canopy photosynthesis presents single point curve with max xin bells period, reducing after bells period.In wadding period, canopy photosynthesis reduces,leaf and culm stricks as leaf-cut area increasing in cut-leaf type cotton,this phenomena present lower leaf area index cause cotton plant stricken.