Drought induced changes in physiological, biochemical and phytochemical properties of Withania somnifera Dun.

Drought (D) stress effects on growth, photosynthetic pigments, photosynthetic electron transport, thylakoid polypeptides and phytochemical variations of Withania (Solanaceae), a tropical medicinal herb were studied. Exposure of plants to D-stress led to noticeable decrease in leaf area, photosynthetic pigments, root and shoot lengths and photosynthetic activity. Well-watered plants maintained high content of total chlorophyll (Chl), root and shoot lengths, leaf area and photosynthesis. We analysed alterations at cellular level of the D-stress-associated proteins at different time intervals. A set of proteins in the range of 34 to 40 kDa showed variations in response to D-stress. Qualitative high performance thin layer chromatography (HPTLC) analysis of root extract obtained from control and D-stressed plants showed quantitative and qualitative variations. Withaferin A content increased 5% under D-stress as compared to control.   Key words: Carotenoids, chlorophyll, fluorescence, leaf area, pigments photosynthesis.

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