薏苡叶片的生长与叶面积的研究

本文以两个不同来源的品种为材料，分析了薏苡叶片的大小、叶面积的测定方法及叶面积的变化与组成，结果表明：薏苡叶片的大小因品种和着生部位（叶序）而异，一般中上部叶片较宽大，基部叶较短小；用长宽法测定叶面积的校正系数也因叶序不同而有一定差异，以中上部和基部叶较大，中下部叶较低，两品种的总平均为０．７２７；叶面积（Ｙ）与叶片的长宽乘积（Ｘ１）和长宽比值（Ｘ２）呈极显著正相关，回归方程分别为Ｙ＝－０．２８６＋０．７３０５Ｘ１和Ｙ＝－６．９２８＋４．９２６８Ｘ２；薏苡一生中叶面积的变化呈一元三次曲线，大约在抽穗末期达最大值，一生都处于淹水条件下的单株叶面积和比叶面积均较低；薏苡在中后期分枝分蘖叶面积占全株的比重大，中上部主茎叶面积占主茎叶面积百分比较高

STUDY ON THE LEAF GROWTH AND LEAF AREA OF JOB′S-TEARS

The leaf size leaf area and leaf area measuring method of Job′stears were studied. The results were shown as follows: The leaf length, widthand thickness (SLA,specific leaf area) of Job′s-tears varied with the varietiesand the leaf position on the main stem. The medium-upper leaves on the main stemwere usually larger and thicker than the basal ones. The value of K, thecalibrated coefficient used to calculate the leaf area with the leaf length andwidth, varied with the leaf position on the main stem too. The average K of0.727 was calculated with the two varieties experimented.There were signifficantcorrelationships between leaf area(Y) and leaf length×width(X 1 ) and length/width (X 2 ), and the regression equations of Y=-0.286+0.7305X 1 and Y=-6.928+4.9268X 2 were found,which could be used to calculate the leaf area.The curve of leaf area per plant in the all growth stage fitted in with cubic equation.The SLA and leaf area of the plants in the dry-farming field which were moistured within all growth stages were larger than those in the irrigated field keeping 3─6cm thickness of the water within all growth stages. The leaf area per plant was largely composed by the tiller leaves while the leaf area of the leaves on the main stem was largely composed by the medium-upper ones at the medium-late growth growth stage.