Photosynthesis-Light Response Curve Derived from Light Absorbed in a Leaf : II. Soybean and Corn Plants

Using the model proposed in this paper, the linear relationship of incident light with photosynthetic rates of soybean and corn leaves was obtained in low light intensity. In this range, efficiencies of light energy conversion for PhAR were 3.5-9.1 %in soybean and 7.4-16.4 %in corn leaves. The linear relationship between light and Photosynthesis started to deviate at light intensity 0.036-0.078 cal (PhAR)/cm^2 min for soybean and at 0.073-0.116 cal (PhAR)/cm^2 min for corn. Using both these values and the chlorophyll contents of a leaf, maximum available light energies used for carboxylation by unit chlorophyll were estimated to be 210-505 cal (PhAR)/ [mg (chl) h] in soybean and 433-698 cal (PhAR)/ [mg (chl) h] in corn leaves. The maximum photosynthetic rates, saturated with light, of corn leaves were estimated to be 130 mg CO_2/(dm^2 h) (form proposed model in this study) and 189 mg CO_2/(dm^2 h) (form reciprocal equation).