Physiological and Biochemical Responses of Turmeric (Curcuma longa L.) Under Drought Stress

Authors: BHARADWAJ, BHIOLINA - California State University; SANATHANAM, SRAVAN KUMAR - Alabama A & M University; PHAM, TRANG - Alabama A & M University; Cantrell, Charles; Wang, Mei; MENTREDDY, SRINIVASA RAO - Alabama A & M University; BASU, CHHANDAK - California State University

Submitted to: Journal of Medicinally Active Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2023
Publication Date: 9/30/2024
Citation: Bharadwaj, B., Sanathanam, S., Pham, T., Cantrell, C.L., Wang, M., Mentreddy, S., Basu, C. 2024. Physiological and Biochemical Responses of Turmeric (Curcuma longa L.) Under Drought Stress. Journal of Medicinally Active Plants. 13:40-55. https://doi.org/10.7275/jmap.2315.
DOI: https://doi.org/10.7275/jmap.2315

Interpretive Summary: For nearly 4000 years, turmeric (Curcuma longa L.) has been one of the most important medicinal plants. In Southern Asia, it has been used in spices, food preservatives, beauty care products, and dyes. Unfavorable environmental conditions, particularly abiotic stresses such as drought, can hinder the growth and development of turmeric, leading to significant production losses. In this study, we investigated physiological and biochemical changes in three turmeric varieties after introducing artificial drought stress by withholding water for 21 days. The net photosynthetic rate, chlorophyll content, moisture content, catalase activity, and the rhizome curcuminoid content were measured in the stressed vs. unstressed control using published methods. Drought stress reduced photosynthetic rates and chlorophyll content, but increased the curcuminoids and catalase activity. The curcuminoid levels increased in general. The greatest increase was in a R-turmerone which spiked from 1.67 mg in control rhizomes to 9.57 in drought stressed rhizomes. This study demonstrates the potential for genetic improvement and utilizing drought stress for improving curcumin production in turmeric.

Technical Abstract: For nearly 4000 years, turmeric (Curcuma longa L.) has been one of the most important medicinal plants. In Southern Asia, it has been used in spices, food preservatives, beauty care products, and dyes. Unfavorable environmental conditions, particularly abiotic stresses such as drought, can hinder the growth and development of turmeric, leading to significant production losses. In this study, we investigated physiological and biochemical changes in three turmeric varieties after introducing artificial drought stress by withholding water for 21 days. The net photosynthetic rate, chlorophyll content, moisture content, catalase activity, and the rhizome curcuminoid content were measured in the stressed vs. unstressed control using published methods. Drought stress reduced photosynthetic rates and chlorophyll content, but increased the curcuminoids and catalase activity in senescing plants compared to that of control. The curcuminoid levels increased in general. Bisdemethoxycurcumin, demethoxycurcumin and a-R-turmerone increased significantly in the drought stressed compared to the control treatment. The greatest increase was in a R-turmerone which spiked from 1.67 mg in control rhizomes to 9.57 in drought stressed rhizomes. Curcumin content of drought stressed rhizomes increased by 50% over the control treatment but was not statistically significant. The total curcuminoid content increased by 106% over the control. This study demonstrates the potential for genetic improvement and utilizing drought stress for improving curcumin production in turmeric.