中文摘要：

为探讨自然条件下母体密度应激对根田鼠F1代性器官指数的影响,通过在围栏内建立不同密度的母体种群获得相应的F1代个体,以此建立了不同密度的子代种群,并测定了母体种群建群者的血浆皮质酮含量,将建立子代种群后剩余的F1代个体带回实验室饲养。实验结束后,测定了全部F1代个体的性器官指数及皮质酮含量。结果表明,高密度母体种群建群者的皮质酮含量显著高于低密度母体种群建群者;出生于高密度母体种群的F1代个体处于高密度子代种群,其性器官指数显著低于出生于低密度母体种群且处于低密度子代种群的F1代个体,而皮质酮含量显著高于后者;出生于高密度母体种群的F1代个体处于低密度子代种群,其性器官指数及皮质酮含量与出生于低密度母体种群且处于低密度子代种群的F1代个体间无显著差异。此外,实验室饲养条件下,出生于高密度和低密度母体种群的F1代个体间的睾丸指数无显著差异。本研究结果说明,在根田鼠种群中,单一的母体密度应激对子代的性器官指数无影响,但生前应激子代在性成熟后,当再次遭遇密度应激时,其性器官指数显著降低,母体密度应激和当前环境对种群的未来繁殖能力具有耦合效应。

英文摘要：

We studied the effects of maternal stress induced by high density on an offspring sex organ index by experimentally altering population densities of root voles（Microtus oeconomus）in field enclosures.High-and low-density enclosed parental populations were established,from which we obtained offspring that were used to establish two low-density offspring populations,respectively,which consisted of 6 F1 voles of each sex originating from either high-or low-density parental populations,and a high-density offspring population,which consisted of 30 F1 voles of each sex from high-density parental populations.The remaining F1 individuals were transferred to cages in the laboratory.Adults of the high-density parental populations had higher corticosterone levels,an indication of physiological stress,than did those of the low-density parental populations.F1 voles from low-density parental populations,when in low-density F1 populations,displayed a greater sex organ index than did F1 voles from high-density parental populations in high-density F1 populations,but the corticosterone level was inverse.The sex organ index and corticosterone level did not differ between the F1 individuals from both low-and high-density parental populations,when in low-density F1 populations.In laboratory,a significant difference in testicle index was not observed between F1 offspring from high-density and low-density parental populations.The results suggest that maternal stress alone induced by high density,did not affect the sex organ index of their offspring,but prenatally stressed offspring displayed a reduced sex organ index when they were exposed to high density during the breeding period.