Seed Germination and Seedling Growth of Dioscorea Deltoidea Wall. EX Griseb. From Kinnaur (Himachal Pradesh) as Affected by Zinc and Copper

We examined the effects of zinc (100–1000 μM) and copper (50–500 μM) on seed germination and seedling growth of a population of D. deltoidea, an endangered medicinal plant species, from Kinnaur (Himachal Pradesh). Zn and Cu treatment of seeds led to enhanced seed germination and seedling growth. In general, Zn was more effective than Cu. Organ-specific differences in response to Zn and Cu were evident as the root growth promotion was found to be stronger than that of shoot. Due to Zn and Cu treatment, TTC reduction ability, a measure of the activity of dehydrogenases, and α-amylase activity in the seeds were enhanced. Concomitantly, the lipid peroxidation in seeds was marginally enhanced by certain concentrations of Zn and Cu that was accompanied by unaltered catalase (CAT) and enhanced ascorbate peroxidase (APX) activity. The promotory influence of Zn and Cu on seed germination and seedling growth could be ascribed to the observed metabolic changes representing diverse processes.