Effects of Zinc and Ascorbic Acid Application on the Growth and Photosynthetic Pigments of Millet Plants Grown under Different Salinity

Abstract

Salinity stress impacts crop growth as well as production. The need for increased food production to feed the increasing population and the limited resources, i.e . optimal quality land and water, require developing strategies to mitigate marginal stresses, including salinity stress, for reasonable expectation of crop production. A pot experiment was conducted in a greenhouse at the National Research Centre, Dokki, Cairo, Egypt in the summer season of 2005 to evaluate the effects of foliar application of ascorbic acid alone or in combination with zinc sulfate on the growth and photosynthetic pigments of millet plants irrigated by tap water (250 ppm, 0.39 dS·m -1 ) or moderate to high salinity irrigation water [2500 ppm (3.9 dS·m - 1 ) and 5000 ppm (7.8 dS·m -1 )]. Increased salinity in the irrigation water decreased the plant growth, biomass, and carotenoid content. Foliar application of ascorbic acid alone increased number of leaves and leaf area, while in combination with zinc sulfate increased the plant height and total plant biomass. However, these treatments had no significant effects on the photosynthetic pigments. This study demonstrates that exogenous application of ascorbic acid can enhance foliar growth which may contribute to increased plant biomass and yield.