Ascorbic acid, a major non-enzymatic antioxidant in plants: Estimation in different potato (Solanum tuberosum L.) tissues

Abstract

Reactive oxygen species (ROS), by-products of aerobic metabolism, were initially recognized as toxic to living cells but now their role in plant growth, signalling and especially response to various stresses is gaining considerable importance. Plants have evolved enzymatic and non-enzymatic antioxidants to overcome the effect of these ROS. Potato is the fourth major cultivated crop and also forms a significant proportion in the Indian diet because of the presence of proteins, nutrients, starch, carbohydrates, vitamins, minerals along with fibres beneficial for human health. In mature tubers L-Ascorbic acid (AA) also known as Vitamin C, is present in relatively high amount. Ascorbic acid is a powerful antioxidant which helps in modulating cellular H2O2 level to a permissible range. The extent of ascorbate synthesis varies in the different potato cultivars depending on the genotype and other factors. This study focused on the estimation and comparison of ascorbate level in various tissues namely tuber, leaf and stem of different potato cultivars at different time intervals during growth under field condition and also storage conditions. The highest ascorbate content was noticed in the leaf tissue of all cultivars. The experimental data as presented in this report suggest that mature tubers contain more ascorbic acid in comparison to the growing tubers. Vitamin C content was found to vary in the tissues under different storage conditions. The apparent fluctuations of ascorbate level as observed in different tissues under storage conditions need to be understood carefully.