Yeast Extract and Lithovit Mineral Fertilizer Ameliorate the Harmful Effects of Drought Stress in Wheat

Abstract

THE effects of two levels of drought stress (25% and 50% of FC) and the control (75% FC) on the growth, some physiological processes and some metabolites in wheat (Triticum aestivum, cv. Masr 2) at seedling (30 days), vegetative (65 days) and yield (160 days) stages were studied. The ameliorative effects of the foliar spray for the harmful effects of drought by the bio-stimulant yeast extract (10%) or the mineral fertilizer lithovit (3.8%) were also studied. The results showed that both levels of drought stress decreased all of the measured growth criteria and chl a and chl b at both growth stages. The foliar spray with yeast extract or lithovit resulted in the alleviation of these inhibitory effects. Carotenoids increased with drought stress but decreased using both foliar spray treatments. Carbohydrates and total soluble proteins decreased under both drought levels, but using yeast extract or lithovit treatment alleviated these effects. Higher activities of catalase, peroxidase and ascorbic oxidase were recorded under the two stress levels, while yeast extract and lithovit treatments inhibited them. At yield stage, both drought levels resulted in severe reduction in all yield parameters, carbohydrates and total soluble proteins contents in the produced grains. Foliar spray with yeast extract or lithovit improved all the measured parameters of yield and increased the contents of the metabolites in the grains. Although lithovit was slightly more effective than yeast extract, the latter treatment seems preferable as it is a natural product with no apparent residual effects on plants and soil.