Alteration induced in the absorption of a photon by Pb in the chloroplast center of leaves of Vigna radiata L

Abstract

Vigna radiata L. is included in a dietary meal worldwide, especially in Asian countries, and is also a part of herbal medicine. It was selected to monitor the photon absorption under Pb metal on the chloroplasts center. The seedlings of Vigna radiata L. were cultured in nutrient solution for 15 days at several concentrations of Pb viz., 0, 50, 100, 150, and 200 ppm. Then harvested, washed, homogenized in ethanol, centrifuged and the supernatants were subjected to spectrophotometric analysis. Results showed that a hypsochromic shift in wavelength was observed under Pb stress which was discussed as an alteration in the absorption of photon wavelength of different pigments observed in the early growing stages. It was observed that the alteration in photon absorption consequently appears in photosynthetic activities, followed by the formation of the excited state of the chlorophyll and the release of energy. Moreover, the shift in wavelength in the UV region showed the synthesis of secondary metabolites. It was concluded the effects of Pb on photon absorption of chloroplast center was strongly reliant on the distribution of pigment concentrations and their absorbance with the formation of compounds that absorb radiation in UV region.