密度对大豆群体冠层结构及光合特性的影响

Effect of density on canopy structure and photosynthetic characteristics in soybean population

以垦农4号大豆为试验材料,在大田条件下,研究了密度对大豆群体植株形态特征、叶面积指数、干物质重、透光率、光能截获量、光合速率、蒸腾速率、气孔导度、比叶重及产量的影响。结果表明:群体冠层结构及光合特性存在差异,高密度与低密度群体之间差异显著;株高、平均茎长及平均柄长均随着密度的增加呈增加趋势,而节数、平均茎粗、平均柄粗及茎柄夹角均随着密度的增加呈降低趋势;不同层次叶面积指数、干物重及冠层的光合有效辐射截获量随着密度的增加而增加,叶面积指数主要集中在冠层中上部,干物重主要集中在冠层中下部。不同层次透光率、光合速率、蒸腾速率、气孔导度及比叶重随着密度增加呈递减的趋势。本试验条件下,密度为36万株/hm2(D3)时,群体产量最高。

With Kennong 4 as the experimental material,we analyzed the effect of density on plant type characteristics,leaf area index,dry weight,radiation transmittance rate,intercepting radiation,photosynthetic rate,transpiration rate,stoma conductance,specific weight,and yield of soybean in the field condition.The results indicated that there were different soybean canopy structures and photosynthetic characteristics.There was significant difference between high density and low density.Plant height,average stem length and average petiole length increased with the increase of density,while node number,average stem diameter,average petiole diameter and average langle between stem and petiole decreased with the increase of density.Leaf area index,dry weight of different layers and total canopy intercepting radiation increased with the increase of density.Leaf area index concentrated in the upper and middle canopy and dry weight concentrated in the bottom and middle canopy.Photosynthetic rate,transpiration rate,stomatal conductance and specific weight decreased with the increase of density.The yield of 3.6×105-plants-per-hm2（D3） reached the highest.