雌雄青杨的磷觅食策略及性别内和性别间相互作用

The lack of knowledge in the root and mycorrhizal fungi traits of dioecious plants, stops us to further understand the foraging strategies of sexes and intra- and inter-sexual interactions. To bridge these gaps, this proposed project will be conducted to survey root and mycorrhizal fungi traits, and foraging sensitivity and precision of root morphology and mycorrhiza of male and female Populus cathayana, and magnitude of intra- and inter-sexual interactions via two-compartment root window-boxes and splitting-root settings, respectively. This project aims to explore the sex-specific characteristics of response to soil phosphorus distribution, and clarify male and female strategies for phosphorus foraging, and illustrate synergetic response patterns to both soil phosphorus distribution and sexual competition, and clarify the mechanisms mediated by root and mycorrhizal fungi traits in sex-specific responses and adaptions of P. cathayana to highly heterogeneous phosphorus. The positive results will be also helpful to develop nutrient control strategies precisely and maintain a long term productivity of P. cathayana plantation.

雌雄异株植物的根系性状及菌根特征尚不清楚，导致无法深入理解不同性别植物的觅食养分策略及性别内和性别间的相互作用。为此，本项目拟以雌雄异株的木本植物青杨为研究对象，借助两室根箱和分根装置，分别测定雌雄的根系性状和菌根特征、根系形态和菌根的磷觅食敏感性和精确性、性别内和性别间相互作用强度，探讨雌雄性别间对土壤磷分布的响应特征，解析磷觅食策略性别差异，探明雌雄植物对土壤磷分布和性别竞争的协调响应规律，阐释土壤磷异质分布下根系性状及菌根特征介导的青杨性别响应差异与适应机制。同时，研究结果将有助于精准制定养分调控策略和维持青杨人工林长期生产力。

根系的功能特征对植物养分的捕获策略有重要影响。然而，根系性状可塑性及其调控的养分吸收策略并不清楚。 根系性状和根际过程介导了杨树各无性系间不同的磷吸收策略；青杨存在性别特异的养分吸收策略，表现在根系形态调整、分泌物释放和菌根真菌共生间存在协同和权衡；磷的供应能够显著增强雄性的抗旱性，但对雌性的影响较小。与雌性相比，雄性抗旱性的增强可能与根际较强的生理可塑性有关；性别特异的相互作用对雌雄青杨生长和抗植食性昆虫的影响，并调控根系酚类代谢物和根际微生物。综上，以上研究进一步验证、充实和完善林木根系生态学相关理论。系统研究了主要人工林树种杨树的根系功能性状特征及其对环境因子的(磷和干旱)响应。鉴别出与环境忍耐和资源利用策略有关的功能性状，为深入研究人工林树种的地下生态过程提供了新的研究途径。