10年生杉木人工林叶片和细根功能性状对土壤磷添加的响应

Leaf and Fine Root Functional Traits Response of 10-Year-Old Cunninghamia lanceolate Plantations to Soil Phosphorus Addition

[目的]揭示10年生杉木人工林叶片、细根功能性状对土壤磷添加的响应,为提高杉木人工林生产力提供科学依据。[方法]在10年生杉木人工林中设置P_(0)(对照)、P_(1)、P_(2)、P_(3)、P_(4)、P_(5)共6个处理,土壤施磷量分别为0、60、120、180、240、300 kg·hm^(−2)·a^(−1),进行了3年模拟磷沉降控制试验,分析了叶面积(LA)、比叶面积(SLA)、叶组织密度(LTD)、叶干物质含量(LDMC)、比根长(SRL)、比根表面积(SRA)、根组织密度(RTD)、可塑性指数(PI)的响应及功能性状之间的相关性。[结果]在土壤磷缺乏情况下,随着施磷浓度程度的增加,杉木的LA、SLA、SRL、SRA均先增加后降低,LTD、LDMC、RTD均先减小后增加。在不同施磷处理下,杉木叶片、细根功能性状的PI平均值分别为0.21、0.16,CV的范围为3.9%~15.9%,属于较弱变异。杉木叶功能性状LTD与LA、SLA在P_(0)、P_(2)处理下呈显著(P<0.05)或极显著(P<0.01)负相关,LTD与LDMC在P_(1)处理下呈显著正相关(P<0.05);SLA与LA在P_(0)、P_(3)处理下呈显著正相关(P<0.05),SLA与LDMC在P_(4)处理下呈极显著负相关(P<0.01)。杉木细根功能性状SRL与SRA在P_(0)、P_(3)、P_(4)、P_(5)处理下呈极显著正相关(P<0.01),SRL与RTD在P_(3)、P_(4)处理下呈显著(P<0.05)或极显著(P<0.01)负相关;RTD与SRA在P_(0)、P_(2)、P_(3)、P_(4)、P_(5)处理下呈显著(P<0.05)或极显著(P<0.01)负相关。[结论]杉木通过协调叶片和细根功能性状的耦合关系响应不同梯度的土壤磷添加,进而形成应对土壤磷含量变化的生存策略。本研究表明,适当的磷添加(P_(2)、P_(3))有利于10年生杉木人工林的土壤养分吸收和生长。

[Objective]To reveal the response of leave and fine root functional traits of 10-year-old Cunninghamia lanceolate plantation to soil phosphorus(P)addition so as to provide scientific basis for its productivity improvement.[Method]Six treatment of P0(control),P1,P2,P3,P4 and P5 were set up in the 10-year-old C.lanceolate plantations.Soil P addition amount was 0,60,120,180,240 and 300 kg·hm−2·a−1 respectively,and simulated P deposition experiment was carried out for three years to analyze changes of functional traits,phenotypic plasticity index(PI),coefficient of variation(CV)and the correlation between functional traits including leaf area(LA),specific leaf area(SLA),leaf tissue density(LTD),leaf dry matter content(LDMC),specific root length(SRL),specific root surface area(SRA),root tissue density(RTD).[Result]In the condition of soil P limitation,with the increase of P addition amount,LA,SLA,SRL and SRA of C.lanceolate increased firstly and then decreased,whereas LTD、LDMC、RTD decreased firstly and then increased.Under different soil P addition treatments,the average PI values of leave and fine root functional traits of C.lanceolate were 0.21 and 0.16 respectively;The range of CV was 3.9%-15.9%,which showed a weak variation;The LTD of C.lanceolate was negatively correlated with LA and SLA under P0 and P2 treatments(P<0.01),and LTD was positively correlated with LDMC under P1 treatment(P<0.05).SLA was positively correlated with LA under P0 and P3 treatment(P<0.05),and SLA was negatively correlated with LDMC under P4 treatment(P<0.01).The SRL of C.lanceolate was positively correlated with SRA under P0,P3,P4,and P5 treatments,and SRL was negatively correlated with RTD under P3 and P4 treatments(P<0.01);RTD was negatively correlated with SRA under P0,P2,P3,P4,and P5 treatments(P<0.01).[Conclusion]Cunninghaia lanceolata developed a survival strategy to cope with changes in soil P content by coordinating the coupling correlation between leaf and fine root functional traits.This research showed that appropriate P addition(P2,P3)was beneficial to soil nutrient absorption and growth of 10-year-old Chinese fir plantation.