Abstract

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.