Light Heterogeneity of Individual Leaf Cause by Cupping Influences
Photosynthetic Characteristics in Pima Cotton
Abstract
Light heterogeneity can lead to the heterogeneity of morphological
structure and physiological functions in different leaves. However,
little attention has been paid to the effect of nonuniform illumination
on morphological structure and photosynthetic performance between the
two symmetrical portions along the main vein within individual leaves.
This experiment was carried out by the method of combining site
determination in the field and shading simulation in the phytotron using
pima cotton which have cupping leaves. In the field, maximum net
photosynthetic rate, leaf area, and leaf mass per area were positively
correlated with daily photo irradiance (DPI), while the chlorophyll
content related negatively with DPI. These results indicated that the
heterogeneity of photosynthetic characteristics between two sides of
along the main vein within individual leaves were related with its
intercepted light energy. Further, the shading simulation experiments
also verified this conclusion. Interestingly, compared to the both
ambient leaves and individual shading leaves, the photosynthetic
characteristics of both ambient leaves and shading leaves in shading
half leaves were changed. Thus, we also discussed that the development
of the photosynthetic characteristics in one side of the main vein in a
leaf was systematically regulated by adjacent side.