摘要
[目的]植物功能性状对种间生态策略的预测作用已得到普遍验证,但其能否预测种内不同生长阶段的生态策略仍缺乏证据。本研究旨在探究根叶功能性状变化如何驱动油松林在不同生长阶段生态策略的调整,及其生态策略对氮添加的适应性机制,可为理解物种生长阶段特异性响应气候变化提供科学依据。[方法]以山西省中条山区中村林场20年和40年生油松天然次生林为研究对象,设置低氮(5 g N/(m^(2)·a))、高氮(15 g N/(m^(2)·a))处理并以不施氮(0 g N/(m^(2)·a))为对照,测定叶片形态性状(比叶面积、叶干物质含量)和化学性状(叶碳、氮、磷浓度,及其化学计量比),根形态性状(根直径、比根长、根组织密度)、根生理性状(根呼吸速率、根有机酸含量)和化学性状(根碳、氮、磷浓度,及其化学计量比),以及菌根真菌性状(菌根侵染率、菌丝密度)。[结果](1)林龄、氮处理及二者交互作用对叶片和菌根功能性状几乎都有显著影响(P<0.05)。20年生油松林具有更高的叶碳、磷浓度和根组织密度、菌根真菌侵染率、菌丝密度,油松林地下资源获取主要依靠菌根真菌,其自身倾向于保守型策略。40年生油松林具有更高的比叶面积、比根长、根呼吸速率、根有机酸含量和根氮、磷浓度,揭示油松林具有资源获取型策略,且比叶面积和比根长呈显著正相关(P<0.05),说明地上和地下资源获取具有协同性。(2)相较对照,不管是低氮还是高氮处理,2个林龄的油松林均为比叶面积和比根长显著增大,20年生林比叶面积增幅分别为9.3%和39.9%,比根长增加15.2%和15.5%;40年生林对应性状的增幅分别为13.3%和13.0%,17.9%和8.6%。相反,菌根侵染率均显著降低,20年生林和40年生林的降幅分别为35.9%、28.0%和24.9%、17.9%。氮添加还显著提高20年生林的叶氮和磷浓度,但降低40年生林的叶氮和根氮浓度。[结论]尽管20年和40年生林均处于快速生长阶段,但20年生林地下资源获取主要依靠菌丝,油松林是保守型策略,而40年生林地上和地下表现出协同的资源获取型策略。氮添加促使油松提高根叶资源获取相关的功能性状,同时降低菌根真菌侵染。
[Objective]While the role of plant functional traits in predicting interspecific ecological strategies is well-established,evidence regarding their ability to predict intraspecific strategies across different growth stages remains limited.This study aims to explore how variations in root and leaf functional traits drive the adjustment of ecological strategies in Pinus tabuliformis forests at different growth stages and to reveal the adaptive mechanisms of these strategies to nitrogen(N)addition.[Methods]In this study,natural secondary forests of P.tabuliformis(20 and 40 years old)in the Zhongcun Forestry Station in Zhongtiao Mountains were selected as the research objects.Three N-addition treatments were established:without N addition(CK,0),low-concentration N(LN,5 g N/(m^(2)·a))and high-concentration N(HN,15 g N/(m^(2)·a)).The study measured a variety of leaf traits,including specific leaf area(SLA),leaf dry matter content(LDMC),and carbon(C),N,and phosphorus(P)concentrations,and their stoichiometric ratios.Root traits including root diameter,specific root length(SRL),root tissue density(RTD),physiological traits such as root respiration rate(RR)and root organic acid content(ROA),and chemical traits like root C,N,and P concentrations,were also measured.Additionally,mycorrhizal fungal traits including mycorrhizal colonization rate(MC)and hyphal length density(HLD)were investigated.[Results](1)Stand age,N treatment,and their interactions had significant effects on almost all leaf and mycorrhizal traits(P<0.05).The 20-year-old P.tabuliformis exhibited higher leaf C and P concentrations,RTD,MC,and HLD.Below-ground resource acquisition in the 20-year-old forest relied primarily on mycorrhizal fungi,with the trees themselves tending toward a conservative strategy.In contrast,the 40-year-old forest showed higher SLA,SRL,RR,ROA,and root N and P concentrations,revealing a resource-acquisition strategy.Furthermore,a significant and positive correlation was found between SLA and SRL(P<0.05)showing synergy between aboveground and below-ground resource acquisition.(2)Compared to the CK,both low and high N treatments significantly increased SLA and SRL in both stand ages.In the 20-year-old forest,SLA increased by 9.3%and 39.9%,and SRL increased by 15.2%and 15.5%,respectively.In the 40-year-old forest,these traits increased by 13.3%and 13.0%(SLA),and 7.9%and 8.6%(SRL).Conversely,MC rates significantly decreased across the board(by 35.9%and 28.0%in the 20-year-old forest;24.9%and 17.9%in the 40-year-old forest).N addition also significantly increased leaf N and P concentrations in the 20-year-old forest but decreased leaf and root N concentrations in the 40-year-old forest.[Conclusion]Although both 20-and 40-year-old P.tabuliformis forests were in rapid growth stages,the 20-year-old forest relies mainly on mycorrhizal hyphae for below-ground resource acquisition,employing a conservative strategy.The 40-year-old forest demonstrated a synergistic above-and below-ground resource-acquisition strategy.Nitrogen addition prompted P.tabuliformis to enhance functional traits related to leaf and root resource acquisition while simultaneously reducing dependence on mycorrhizal colonization.
作者
孙剑
梁文佳
梁佳芳
杨秀云
刘碧桃
Sun Jian;Liang Wenjia;Liang Jiafang;Yang Xiuyun;Liu Bitao(Zhongtiaoshan Forestry Bureau of Shanxi Province,Linfen 043004,China;College of Forestry,Shanxi Agricultural University,Jinzhong 030801,China;Shanxi Key Laboratory of Edible Fungi for Loess Plateau,Jinzhong 030801,China)
出处
《山西农业大学学报(自然科学版)》
北大核心
2026年第1期48-59,共12页
Journal of Shanxi Agricultural University(Natural Science Edition)
基金
山西省基础研究计划(自由探索类)面上项目(202103021224157)
山西农业大学横向科技项目(2023QT190)。
关键词
生存策略
功能性状
菌根
氮添加
油松
林龄
Survival strategy
Functional traits
Mycorrhiza
Nitrogen addition
P.tabulaeformis
Stand age
