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雌雄异株植物通常呈现性别二态性,但其雌株和雄株的根系性状和养分吸收如何响应相邻植株的性别变化尚不清楚.本研究以中国广泛栽培的雌雄异株植物桑树(Morus alba)为试验对象,在水培环境下,采取雌-雌、雄-雄和雌-雄3种组合种植模式进行试验.植株生长3个月后,分别测定雌雄植株根系的解剖结构、形态、营养浓度和生物量.研究结果表明,在水培环境中,与同性相邻相比,当桑树雄株与异性相邻时,其根系木质部变小,根和径生物量减少,根系中N、P、K浓度增加.相比,当桑树雌株与异性相邻时,其根系木质部变大,细根长度、表面积和体积以及根系δ13C和N、P、K浓度增加.雌雄植株根系δ13C和N、P、K浓度的变化与根系性状的改变有关.这些结果表明,相邻植株的性别影响了雌雄桑树根系解剖结构和形态.同时,雌雄植株对相邻植株性别改变的响应呈现性别二态性,这种二态性响应影响了雌雄植株水分利用效率和营养吸收.这些发现对于理解森林和自然系统中其它雌雄异株物种的种群动态变化具有重要意义.“,”Aims Dioecious plants present sexual dimorphism,but how the root traits and nutrient uptake of female and male plants in dioecious species response to the sexual identity change of the neighbor plants are poorly understood.Methods Mulberry (Morus alba L.),a dioecious plant widely distributed in China,was employed in our study.Male and female plants were grown with neighbors of the same and opposite sex for 3 months.At harvest,the root anatomy,root morphology,nutrient concentrations and biomass accumulation were measured.Important Findings When grown with the opposite sex,the males showed decreases in root xylem size,biomass of root and stem and increases in root N,P and K concentrations compared with grown with the same sex.By contrast,females showed significant increases in xylem size,fine root system (e.g.fine root length,root surface area and root volume),root carbon isotope composition (δ13C) and root N,P and K concentrations.The changes in the δ13C and N,P and K concentrations in male and female plants were associated with the changes of root traits.These results demonstrated that the sexual identity of the neighboring plants affected root anatomy and morphology of female and male mulberry plants.Meanwhile,the responses of female and male plants to the sex change of the neighboring plants showed sexual dimorphism,which influenced water-use efficiency and resource acquisition.These findings are important for understanding the population dynamics of other dioecious species in forestry and natural systems.