Acclimation of chlorophyll fluorescence activities under drought stress in Avena species

Abstract

Acclimation of chlorophyll fluorescence was investigated in seven oat species (viz., Avena sativa, A. strigosa, A. brevis, A. vaviloviana, A. abyssinica, A. marocana and A. sterilis) under drought stress environment. Significant variation was observed among the different species of oats in relation to various parameters of chlorophyll fluorescence under stress and non stress environment. The level of chlorophyll fluorescence (Fs) and maximal fluorescence (Fms) were significantly decreased in all the species except in A. sterilis. The quantum yield and elctron transport rate (ETR) also decreased under stress. The photochemical quenching (qp) was equal under stress and non stress environment. However, drought stress increased non-photochemical quenching of chlorophyll fluorescence (qN). The photochemical efficiency of PSII (Fv/Fm) under stress was less affected at vegetative stage but reduced at flowering stage. Minimum decrease in Fv/Fm was recorded in A. abyssinica, A. sativa and A. sterilis at vegetative stage and in A. sterilis at flowering stage indicating the less effect of stress environment on photochemistry of PS II which intern their drought stress tolerance. As the tolerance of PSII against drought is high, the fluorescence parameter Fv/Fm is useful for selection of genotypes for drought tolerance.