MODELING LIGHT ACCLIMATION OF PHOTOSYNTHETIC RESPONSE IN DIFFERENT AGES OF VINE LEAVES

The aim of this study is to estimate a leaf’s 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 (A_max) and the net photosynthetic rates (Pn) were different from each other around 30-40% throughout the season of leaves.
Meanwhile, the light saturation point (I_s) 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.

VII International Symposium on Light in Horticultural Systems

R. Chiarawipa, Y. Wang, X.Z. Zhang , Z.H. Han, M. Rueangkhanab

carbon assimilation, photosynthetic capacity, photosynthesis model, light intensity, seasonal change

https://doi.org/10.17660/ActaHortic.2012.956.28