松材线虫病疫区黑松的气候敏感性差异及其水分机制研究OA

[Objective]Pine wilt disease is a key factor in the widespread mortality of Pinus thunbergii,and climate change may also influence the disease resistance of P.thunbergii by regulating its physiological adaptation.Investigating the differences in climate sensitivity and water relations among infected,dead,and healthy black pines will reveal the intrinsic physiological mechanisms underlying the susceptibility of black pine to pine wilt disease and the patterns of post-infection changes in water physiological,informing strategies for breeding and controlling disease in black pines.[Method]This study investigated symptomatic and healthy Japanese black pines in Changdao,Shandong Province,integrating dendroclimatological and stable isotope techniques to analyze the responses of radial growth,water use efficiency(WUE),and water source strategies to climate change,thereby elucidating their association with PWD-induced mortality.[Result]1)The tree rings of infected trees already ex-hibited higher climate sensitivity during their healthy stage compared to persistently healthy pines,as reflected in stronger climatic constraints in ring parameters,greater variability in ring index,and stronger correlations with temperature and precipitation.This heightened climate sensitivity was associated with increased susceptibility to PWD.2)Infected pines responded to water stress by increasing WUE(WUE increased by 0.22 g·kg-1),but exhibited significantly lower needle water potentials(-13.95 MPa and-9.60 MPa)than healthy individuals(-7.53 MPa and-6.01 MPa),indicating impaired water transport systems.3)Hydrogen and oxygen isotope tracing revealed a signif-icantly higher proportion of shallow soil water(0-60 cm)usage in infected trees,reflecting root dysfunction,reli-ance on more unstable water sources,and impending hydraulic failure.[Conclusion]This study proposes a"cli-mate-water-pathogen"synergistic mechanism:climate warming exacerbates water stress and reduces pine resistance,while nematode infection further disrupts water transport,forming a positive feedback loop.These insights provide a physio-ecological basis for predicting the dynamics of black pine forests under climate change.