小麦冠层结构与光分布研究

１９８７～１９８９年分别在江苏沐阳和南京卫岗进行了小麦冠层结构与光分布及产量形成关系的研究。结果表明，小麦叶面积指数、最大叶面积密度出现的高度及叶倾角影响光在冠层内的分布，消光系数的垂直分布可反映叶面积和光的空间分布状况。低产群体的最高叶面积指数小于４．０，最大叶面积密度出现部位较低，消光系数分布均匀，但漏光严重，光能利用率低；过旺群体最大叶面积指数过大，最大叶面积密度出现部位较高，消光系数呈上大、中小分布，光在冠层上部递减迅速，中下部光环境差，叶片早衰，净同化率低；高产群体叶面积及其垂直分布合理，孕穗期最大叶面积密度出现在相对高度０．６０～０．６５处，冠层中下部消光系数较大，上部较小，利于光向冠层深处透射，冠层５０ｃｍ处透光率４０％～６０％，地面透光率２．５％～３．０％，净同化率较高，产量最高。

Canopy Structure and Light Distribution in Winter Wheat

The study was carried out at the experimental bases of Naming Agricultural University set up in Shuyang County,Jiangsu province and Weigang,Nanjing,respectively. The relative height for the maximum leaf area density aM (z)in the canopy reduced from booting to anthesis and then increased with the advance of development and the increment of nitrogen fertilizer.The leaf area index (LAI) affected the vertical distribution Of leaf area and light attenuation through the canopy. This could be reflected by the vertical distribution of light extinction coefficient (K). At low LAI canopies,the relative height of aM (z) was lower and the vertical distribution of K was even. At high LAIs canopies,the relative height of aM (z) was higher and the K value was greater in the canopy's upper parts than that in the middle parts. Under high-yielding conditions the maximum LAI was about 6. 0-7. 5,the vertical distribution of leaf area was symmetry to the canopy's middle layer and K was lower in the upper parts.