High Light Acclimated Developing Primary Leaves of Wheat Seedlings Generate Signal for Stress Adaptation through Super Oxide Dismutase

Abstract

Wheat seedlings grown in petri dishes were acclimated to high light during their development and subsequently were subjected to osmotic stress by application of polyethylene glycol (PEG). The photochemical efficiency of photosystem II (PS II) of the acclimated seedlings was found to be higher than that of non-acclimated ones under osmotic stress during senescence. The damage of the photosynthetic apparatus seems to be mediated by reactive oxygen species. The higher level of lutein (Lut) and superoxide dismutase (SOD) activity in acclimated seedlings suggest their involvement in the protective mechanism. The senescing leaves, although in a deteriorating phase, exhibit tolerance to osmotic stress due to the adaptation potential acquired earlier during high light (HL) acclimation.