Adaptive advantages of wood anatomical–hydraulic features linked to sex in a tropical dioecious species

Key message Anatomical traits and features of Amphipterygium adstringens wood and hydraulic properties, both linked to sex, explain the performance of the species in its ecological niche. Androic and gynoic dioecious species respond structurally and functionally to the environmental conditions where they live. How are adaptive advantages manifested by each sex, from the anatomical water transport system to gain hydraulic efficiency? How does the species use the ecological niche by each sex in a dry competitive environment? Amphipterygium adstringens is an endemic, dioecious tree in Mexico. We analyzed the morphometric anatomical features of wood samples from trees to differentiate the functionality of the xylematic system by sex. Physiological indices such as relative hydraulic conductivity, vessel grouping, and vulnerability were estimated. A discriminant analysis was carried out to differentiate hydraulic efficiency by sex. The ecological niches of both sexes were defined using Ripley’s bivariate function. The sizes of the vessels and fibers were significantly higher in the gynoecious wood samples than in the androecious wood samples. Rays in the androecious wood samples were larger than those in the gynoecious wood samples. There was a significant difference between sexes in all the indices estimated. The discriminant analysis showed that gynoecious trees have a better functional response, are able to better adapt to drought, and have higher water transport security. The spatial correlation pattern between adults of both sexes showed independence. Hydraulic efficiency and security are the key features of gynoecious tree survival, while vulnerability to cavitation is a risk factor for androecious trees. The performance of A. adstringens based on wood anatomical traits and hydraulic properties revealed an advantage for gynoecious trees, and susceptibility was linked to androecious trees.