Determination on Color Scale and Photosynthetic Parameters of Different Aged Distylium buxifolium Leaf in Winter

Determinations were conducted on leaf index, color scale and photosynthetic parameters of different aged Distylium buxifolium leaves in January of 2015, in Lishui, Zhejiang province. The result demonstrated that leaf index and color scale of different aged leaves had great difference. The length, width, perimeter and area of autumn leaf was evidently higher than that of summer and spring leaves. Uniform color space determination indicated that luminance (L*) was order by autumn leaf>spring one>summer one, while chrominance (a*) of autumn leaf was red. Photosynthetic parameters of different aged leaves had difference. Pn, Tr, Tf, Gs, WUE and Ci increased with PAR. Pn, Gs and Tr had great difference among different aged leaves, spring leaf was always higher than summer and autumn leaf. Tf and WUE of different aged leaves had similar change, as well as Ci