| In the context of global climate changes,plants,as the most important component of terrestrial ecosystems,can respond to those changes in various ways.Leaf traits are the result of interaction between plant evolution and environmental changes,and have been widely used as indicators of plant adaptation to the environments.In the present study,we analyzed leaf traits of two related species,Caragana liouana and C.microphylla,and their relationships with geographical and climatic factors.We aimed to explore the responses and adaptations of C.liouana and C.microphylla to environmental changes,which might to a certain extent provide a support in understanding the adaptation and response of Caragana species to environmental changes and the geographical distribution of the two species under global climate changes.The results showed that:(1)The leaf traits of C.liouana varied greatly among different provenances,with the leaf C/P having the largest coefficient of variation(24.31%),and with the LT having the lowest value of coefficient of variation(5.4%).All the leaf traits except LL/LW and leaf C content have significant differences among provenances(P<0.05);There were significant correlations among the leaf traits in C.liouana,and DW,PL/PW,LW,PL,etc.were significantly related to other leaf traits;Linear regression analysis showed that the leaf traits of C.liouana has a significant response characteristic with the change of mean annual precipitation(MAP),mean annual temperature(MAT)and altitude.By performing the multiple linear regression analysis,MAP was significantly related to LW,PL,PW,PL/PW,SPAD,LT,DW,MSLA,SLA,LDMC,leaf C concentrations,leaf N concentrations,leaf P concentrations,leaf C/N,leaf C/P has a significant effect.The mean annual temperature(MAT)has a significant effect on LL and the leaf C/N.The interaction between MAP and MAT had an effect on the LT and LL/LW,PW,SPAD,SLA,leaf N concentrations,and leaf C/N of C.liouana.Although some leaf traits are significantly affected by MAT,the interaction between MAP and MAT,the MAP was considered to be the main factor affecting the variation of the most leaf traits of C.liouana.(2)Leaf traits of C.microphylla had a large variation among different provenances,with DW having the highest value of coefficient of variation(22.46%),and with LT having the lowest value of coefficient of variation(5.41%).All leaf traits,except MSLA and C/P,showed significant differences among provenances(P<0.05);Significant correlations were found in the leaf traits of C.microphylla,among which LW,PW,MSLA had significant correlations with other leaf traits,while the LT had no correlation with other leaf traits.Linear regression analysis showed that leaf traits of C.microphylla changed significantly with the change of MAT,MAP and altitude.As shown in the multiple regression analysis,temperature is the most important factor influencing the change of leaf traits of C.microphylla,although the interaction effect of MAP and MAT was also significant in LT.Through multiple linear regression analysis,the MAT was significantly related to LL,LL/LW,PL/PW,SPAD,DW,SLA,PW,LDMC,leaf N concentrations,leaf C/N and leaf N/P of C.microphylla.The MAP had a significant effect on LW,LL/LW and leaf C concentrations,and the interaction of MAT and MAP has a significant effect on LT and LDMC.Although some leaf traits are significantly affected by the mean annual precipitation,the interaction between the MAT and the MAP,the main factor affecting variation of the most leaf traits of C.microphylla.(3)The two closely related Caragana species,C.liouana and C.microphylla have been found to occupy distinct environmental conditions.By performing the two-way analysis of variance,we found the interactive effect of species and provenance,the interactive effect of species and provenance was found to be significant on most of the leaf traits,which might suggest that differentiation in these leaf traits has occurred as the two species become adapted to different environments. |
