Vegetos

Abstract

Low temperature conditions can cause degradation of the thylakoid structure and distortion in light-dependent photosynthetic reactions and are a major factor limiting crop yields. In the present study, we have demonstrated differential responses of three varieties of V igna subjected to low temperature stress. Despite the decrease in the photochemical efficiency of PSII, var. RMG 268 showed highest ETRmax, PPFDsat and ΔF/Fm’ values followed by var. K-851 under low temperature stress. Var. Anand (sensitive) showed a maximum decrease in photosynthetic capacity under low temperature stress. Based on the light curve measurements it seems reasonable to conclude that the photoprotection mechanisms induced by low temperature stress are more efficient in the var. RMG 268 than in var. K-851 and var. Anand. This can be, up to a certain extent, substantiated by the enhancement of the cyclic electron transport around the PSI, in the initial days of stress in var. RMG 268 which can contribute to lessening the excitation pressure on PSII. We can conclude that the low temperature stress-induced structural rearrangement of chloroplasts can also contribute to the development of a more efficient heat dissipating mechanism in var. RMG 268 plants. In our study, the photosynthetic processes in particular, to sustained low temperature treatments were measured non invasively, typically by the analysis of chlorophyll fluorescence emission. These technical advantages of chlorophyll fluorescence approaches can make it a popular technique among plant breeders (e.g., for crop phenotyping and monitoring), biotechnologists, plant physiologists, farmers, gardeners, foresters, ecophysiologists and environmentalists.