Spectral variations associated with anthocyanin accumulation; an apt tool to evaluate zinc stress in Zea mays L.

Abstract

ABSTRACT The correlation between anthocyanins content and accumulation of zinc (Zn) in leaves of Zea mays was investigated and this was considered as a mode of assessing the intensity of Zn toxicity. Characterisation and quantification of leaf pigments were done in 45 d old maize plants exposed to different concentrations of Zn (0.0, 0.65, 1.30, 1.95 g Zn Kg−1 soil), and the enhancement in the accumulation of anthocyanins and degradation of chlorophyll was detected by the spectral analysis performed in the leaf extract of plants as the Zn content in the shoot increases. The role of anthocyanins in safeguarding photosynthesis and chelation of Zn was critically evaluated using chlorophyll a fluorescence responses and computational DFT-B3LYP structural analysis of anthocyanins-Zn complex has been performed using 6-311++ G (df, p) basis set. It was concluded that the accumulation of anthocyanins can act as an indicator of the intensity of Zn stress and this anthocyanins have a lesser potential to maintain photosynthetic efficiency in Z. mays, but plays a prominent role in metal chelation as the anthocyanins-Zn complex is a stable molecule.