浑善达克沙地黄柳小枝功能性状对风蚀环境响应的性别差异

Sex differences in response of twig functional traits to wind erosion of Salix gordejevii in Hunshandake sandy land

植物功能性状及性状间权衡关系对揭示植物生长策略、资源分配模式以及探讨其生理生态过程的内在机制具有重要意义,但针对雌雄异株植物功能性状对其生境响应的性别差异却鲜有报道。以雌雄异株植物黄柳当年生末端小枝为研究对象,从枝水平、叶水平比较雌雄植株功能性状及性状间权衡关系对风蚀环境响应的性别差异。结果显示:小枝水平上,对照环境下雌雄植株茎干重-总叶干重之间的权衡均倾向于总叶干重,风蚀环境下则倾向于茎干重,且雌株权衡值分别为雄株的4.3倍和3.7倍;雌雄植株茎干重-总叶面积的权衡在各生境下均偏向于茎干重,两性的权衡值差异不大。叶水平上,相同叶片干重下,风蚀对雄株叶片面积生长的抑制作用更显著;雌株叶片干重与叶柄干重呈等速生长关系,而雄株呈小于理论值1的异速生长关系,且在风蚀环境中,相同叶柄干重下,雌株叶片干重的累积速率比雄株快。研究表明,黄柳雌雄植株小枝各功能性状间的关系对风蚀环境具有不同的响应,雌株比雄株更倾向于将资源投资在光合器官生长中,且风蚀对雄株光合器官生长的抑制作用更显著。

Trade-off relationships among plant functional traits are key variables for revealing plant growth strategies and resource allocation patterns and exploring the underlying mechanisms of their physiological and ecological processes.Dioecious plants have been considered to be a consequence of different requirements for disseminating pollen and producing fruits and seeds,and played major roles in maintaining the function of terrestrial ecosystems.Previous studies have shown that sexual differences in trade-off relationships among twig components in dioecious species existed,and females tended to have more photosynthetic organ area,mass and stoichiometric element contents than males.The trade-off relationships were not only determined by the genetic characteristics of plants,but also influenced by external environmental factors.However,little attention has been paid to sex differences in the response of functional traits to habitat in dioecious plants.To explore the sex differences,male and female Salix gordejevii shrubs growing on inter-dune land(no erosion)and on the windward slope(20 cm wind erosion)of the dune in Hunshandake Sandy Land were chosen and their twig functional traits,such as lamina mass,lamina area,petiole mass,and stem mass were measured,respectively.The results showed that at the twig level,the trade-offs between stem mass and total leaf mass of males and females in control condition were beneficial for total leaf mass,while that in wind erosion group were beneficial for stem mass.The trade-off values of females were 4.3 times and 3.7 times that of males,respectively.The trade-offs between stem mass and total leaf area in both sexes were beneficial for stem mass under control and wind erosion condition,and there was no difference in the trade-off value between the sexes.At the leaf level,the negative impact of wind erosion on males was greater than that on females in growth of lamina area under the same lamina mass.Furthermore,an isometric relationship between lamina mass and petiole mass was existed in females,while an allometric relationship with a slope<1.0 was existed in males.In the wind erosion condition,the accumulation rate of lamina mass in females was faster than that in males under the same petiole mass.Our results demonstrated that the relationships among twig functional traits of male and female S.gordejevii had different responses to wind erosion,with females tending to invest more resources in the growth of photosynthetic organs than males.Meanwhile,wind erosion inhibited the growth of photosynthetic organs more in males than in females.These reflected resource allocation strategy and environmental adaptation in both sexes.