MODELING LIGHT ACCLIMATION OF PHOTOSYNTHETIC RESPONSE IN DIFFERENT AGES OF VINE LEAVES
The aim of this study is to estimate a leafs photosynthetic acclimation to light conditions in 5 different ages of a 10-year-old grape leaf (Vitis vinifera L. × Vitis labrusca L. Kyoho) during the growing season (early May to late September). The photosynthetic capacity model was considered and described as based on a non-rectangular hyperbola. The light response of photosynthesis was also analyzed by using linear and non-linear regression. Photosynthetic acclimation to light showed the highest curve at 8 weeks after the leaf unfolded. The values of gross carbon assimilation (Amax) and the net photosynthetic rates (Pn) were different from each other around 30-40% throughout the season of leaves. Meanwhile, the light saturation point (Is) during each stage of growth of the leaf had reached the peak ≈700-1,000 mol m-2 s-1. In addition, the estimated values were highly correlated with the observed values of the leaf photosynthesis responses to light variations at 8 weeks after unfolding (r2=0.82**). Thus, a measurement of the photosynthetic acclimation provided here might be useful for estimating the photosynthetic light responses among the seasonal and diurnal variations.
Chiarawipa, R., Wang, Y., Zhang , X.Z., Han, Z.H. and Rueangkhanab, M. 2012. MODELING LIGHT ACCLIMATION OF PHOTOSYNTHETIC RESPONSE IN DIFFERENT AGES OF VINE LEAVES. Acta Hort. (ISHS) 956:255-260
carbon assimilation, photosynthetic capacity, photosynthesis model, light intensity, seasonal change