Zinc-induced changes in morpho-physiological and biochemical parameters in Artemisia annua

Responses of Artemisia annua to different concentrations of zinc [50, 100, 200, 300 and 400 µg g-1(soil dry mass)] were studied during plant ontogeny. Total leaf area, dry mass of leaves, length and dry mass of shoots and roots increased with the age of the plant but the magnitude of increase declined significantly under the influence of Zn treatment. Net photosynthetic rate, intercellular carbon dioxide concentration and stomatal conductance were highest at flowering stage in control and treated plants and decreased at post flowering stage. Contents of chlorophyll a, chlorophyll b, carotenoids, proteins and nitrate reductase activity in leaves increased from pre-flowering to maximum level at flowering stage and decreased thereafter in both control and treated plants. Presence of Zn in the soil drastically decreased/inhibited all the parameters, and the magnitude of decline increased with increasing Zn concentration.