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

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 a turmeric variety after introducing artificial drought stress by withholding water for 21 days. Net photosynthetic rate, chlorophyll content, moisture content, catalase activity, and rhizome curcuminoid content were measured in stressed vs. unstressed control plants. Drought stress reduced photosynthetic rates and decreased chlorophyll content by 27.9%, but increased the curcuminoids and catalase activity in senescing plants by 90.2% and 55.1 %, respectively, compared to control. The curcuminoid levels increased in general at the end of the 21-day drought-stress period. 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. Understanding the molecular and physiological responses of turmeric plants under drought stress will assist researchers in developing drought-tolerant cultivars of turmeric by incorporating the stress-tolerant traits into plant breeding programs. The information from our research can also assist agronomists in developing turmeric cultivation management practices by optimizing growth conditions or altering external inputs like irrigation or the addition of fertilizer.