Abstract
Seed priming increases tolerance of plants against various environmental stresses. Although ample literature is available that depicts the beneficial effects of priming under different environmental stresses, the information on induction of tolerance to Pb stress through seed priming with ascorbic acid (AsA) is limited. Therefore, this study was performed to examine the effect of seed priming with AsA (50 and 100 mg L-1), hydropriming and without priming (control) on physiochemical processes of okra cultivars (Subz-Pari and Arka Anamika) under Pb stress (0, 100 mg L-1). Pb stress caused a considerable decline in plant growth and photosynthetic pigments. Contrarily, Pb stress exhibited rise in the contents of total amino acids, free proline, total soluble proteins and AsA. The POD, CAT, and SOD activities were recorded highest at 100 mg L-1 of Pb. Moreover, Pb stress markedly increased H2O2 and MDA levels that triggered oxidative stress. However, plants raised from seed primed with AsA and water exhibited better growth and had higher chlorophylls, free proline, total proteins, total amino acids, AsA and activities of enzymatic antioxidants. Priming with AsA (50 mg L-1) induced better tolerance to Pb stress in okra plants. Plants of cv. Arka Anamika exhibited greater tolerance to Pb than that of cv. Subz-Pari as was evident from higher plant fresh and dry masses.