Sexual response of black poplar (Populus nigra L.) seedlings to water deficit stress

Black poplar (Populus nigra L.) is one of the dioecious species that is planted in a large area for forestry and wood production in different regions of Iran, but there is less information about its sexual response to water scarcity. In the present study, this plant was used as a model species against water deficit stress, and some morphological and physiological responses of a male clone (62/127) and a female clone (62/154) of black poplar were investigated. A factorial experiment was conducted based on completely random design with four replications. There were four irrigation levels (100, 75, 50, and 25% of field capacity) and two gender or sexes (male and female). Seedlings were irrigated for 120 days in a pot experiment. The results showed that the effect of drought and gender (sex) was significant on many of investigated traits. The sex × irrigation regime interaction effect was significant for height growth, total biomass, stomatal conductance, and transpiration. In all the drought treatments, males plants had higher values of many traits than that for females. It was concluded that that, in the studied black poplar clones, males black poplar were less sensitive to water deficit stress than that for females.