Drought Stress Drives Sex-Specific Physiological and Biochemical Differences in Female and Male Litsea cubeba

Numerous studies have focused on dioecious plants and their sex-specific responses to drought stress. However, sexual dimorphism in drought stress responses between male and female Litsea cubeba, a dioecious species significant to the terrestrial ecosystem in China that is frequently exposed to drought conditions, remains insufficiently characterized. In this study, we examined the sex-specific physiological and biochemical responses of L. cubeba to natural drought stress. The results revealed that natural drought induced significant sexual dimorphism in physiological and biochemical traits of L. cubeba. Females exhibited a higher malondialdehyde (MDA) content than males under prolonged drought conditions; females also exhibited significantly higher catalase (CAT) and peroxidase (POD) activities in both leaves and roots compared to males, with the average CAT and POD activities of all varieties increasing by 104.28% and 23.67% in leaves and 51.17% and 174.57% in roots, respectively. Meanwhile, the dehydrogenase (DHA) activity and chlorophyll (chl) and carotenoid levels of females were higher than those of males. The contents of proline (Pro), soluble sugar (SS), abscisic acid (ABA), and jasmonic acid (JA) in females were significantly higher than those in males. Our results demonstrated that females possess a greater tolerance to natural drought stress than males; this is due to their more efficient antioxidant system, better osmotic adjustment, lower chlorophyll degradation rate, and higher concentrations of ABA and JA, which aid in stomatal closure and facilitate the reactive oxygen species (ROS)-scavenging abilities of females in response to drought stress. Our findings provide evidence that dioecious L. cubeba may adopt distinct survival strategies during natural drought events and enhance our understanding of sexually dimorphic responses to drought stress in L. cubeba.