Physiological and metabolic changes in two Himalayan medicinal herbs under drought, heat and combined stresses

• Published in: Physiology and molecular biology of plants 2021-07, Vol.27 (7), p.1523-1538
• Main Authors: Pandey, Veena, Tiwari, Deep C., Dhyani, Vibhash, Bhatt, Indra D., Rawal, Ranbeer S., Nandi, Shyamal K.
• Format: Article
• Language: English
• Subjects: Antioxidants; Bioactive compounds; Biological activity; Biological and Medical Physics; Biomedical and Life Sciences; Biophysics; Biosynthesis; Carbon dioxide; Carboxylation; Catalase; Cell Biology; Chlorophyll; Climate variability; Combined stress; Drought; Environmental stress; Exposure; Heat; Heat stress; Heat tolerance; Herbal medicine; Herbs; Hydrogen peroxide; Life Sciences; Linalool; Malondialdehyde; Medicinal herbs; Medicinal plants; Metabolic response; Metabolism; Metabolites; Moisture content; Pharmaceutical industry; Pharmaceuticals; Photosynthesis; Physiology; Plant Physiology; Plant Sciences; Proline; Stomata; Stomatal conductance; Superoxide dismutase; Transpiration; Water content; Water deficit; Water use; Water use efficiency
• ISSN: 0971-5894; 0974-0430
• DOI: 10.1007/s12298-021-01027-w

Valeriana jatamansi Jones and Hedychium spicatum Ham-ex-Smith are important medicinal herbs of the Himalayan region, which are highly demanded by pharmaceutical industries. Climatic variability especially increasing temperature and water deficit affects the growth and productivity of these species. In addition, increased temperature and water deficit may trigger the biosynthesis of medicinally important bioactive metabolites, which influence the quality of raw plant material and finished products. Therefore, V. jatamansi and H. spicatum plants were undertaken and subjected to different levels of drought (no irrigation), heat (35 °C), and combined stresses for investigating their physiological and metabolic responses. Both the treatments (individually and in combination) reduced relative water content, photosynthesis, carboxylation efficiency, chlorophyll content, while increased intracellular CO 2 , malondialdehyde and H 2 O 2 content in both the species. Transpiration and stomatal conductance increased under heat and reduced under drought stress as compared to control. Water use efficiency was found to be increased under drought, while reduced under heat stress. Protein, proline, carotenoid content and antioxidant enzymes activities (superoxide dismutase, peroxidise, catalase) initially increased and thereafter decreased during late stages of stress. Exposure of plants to combined stress was more detrimental than individual stress. In V. jatamansi , exposure to drought stress significantly ( p