Research On Resource Allocation And Mechanism For Gender Difference Of Dioecious Shrub Rhamnus Schneideri Var.manshurica

This research selected the dioecious shrub Rhamnus schneideri var.manshurica as research species to investigate the possible mechanism of gender differences in dioecious plants under reproductive pressure.Also provide argument supports for the future research of dioecious plants.In the experiment of resource allocation of R.schneideri var.manshurica.Choose plants which have similar growth and nature condition as research samples during flowering and fruit season.investgate foliage biomass?flower biomass and fruit biomass for each research samples.The results show the reproductive biomass(including flower and fruit biomass)was significantly different between genders(P<0.001),but there was no significant difference between genders regarding the foliage biomass(P>0.05).This results means although females spend more biomass in reproductive activity than males,Females did not show less foliage growth than males.We speculated that this results may be due to compensation mechanism.Light responses of photosynthetic capacity and the estimated light photosynthetic curves were different between the male and female.When the light intensity was less than 500 ? mol·m-2·s-1,there were no significant difference between female and male.But when the light intensity was between 500 u mol·m-2·s-1 to 2000 ? mol·m-2·s-1,Female show higher photosynthetic capacity than male.The results of chlorophyll fluorescence experiment shows that Fv/Fm of female was significantly higher than that of male plants in flowering season(P<0.001),and Fv/Fm was no significant difference between female and male in fruit season(P>0.05).We conclude that the relationship between foliage growth and reproductive growth does not agree with trade-off theory in R.schneideri var.manshurica,Females did not show less vegetative growth than males,lt is due to their higher photosynthetic efficiency and carbon fixation capacity.This higher photosynthetic capacity is a compensatory mechanism for Females whit higher reproductive pressure.