Responses Of Leaf Traits Of Robinia Pseudoacacia And Prunus Armeniaca To Different Aspects And Their Influencing Factors Of Beishan Mountain In Lanzhou

It is one of the hot spots of ecological research that the response mechanism and adaptation strategies of plants to the environment.Aspect is one of the important environmental gradients.Plants will show different adaptation strategies in different aspects.Robinia pseudoacacia and Prunus armeniaca,are two common temperate deciduous trees,with light-loving,drought-resistant,adaptable and other characteristics.The response and adaptation mechanisms of different tree species to environmental changes are not the same.In this study,the Renshou Mountain as the research area and selected three representative mountains,set up three plots on the south,east,west,north slope and the top of each hills to collect samples of leaves of robinia and apricot trees and soil in layers(0~20,20~40 and40~60cm)during its vigorous growth period.Then soil factors(soil water,salinity,bulk density,pH,organic carbon,total phosphorus)and leaf properties of robinia and apricot trees(including leaf vein density,vein diameter,area,thickness,dry matter content,water content)were measured.The changes of leaf traits of robinia and apricot trees with aspects and their responses to soil factors were analyzed.The main results are as follows:(1)There were significant differences in leaf traits between robinia and apricot(P<0.01).The VD,SLA,LDMC of robinia was significantly higher than that of apricot,however,the VDi,LT,LA and LWC were significantly higher than that of robinia(P<0.01).The variation coefficient of leaf traits of the two tree species is that:LWC(9.16%and 5.70%)were smaller,is small variability,all the other leaf characters showed medium variability.(2)Leaf traits of robinia and apricot changed with slope direction(from the south slope to the east,west and then to the north slope)is that:VD and SLA are decreasing,The maximum value of VD appears in the south slope(83.32mm/mm~2,39.24mm/mm~2),the maximum of the SLA appears at the top(245.77cm~2/g,243.01cm~2/g).The VDi,LT,LDMC of both species showed a general trend of increasing,The maximum value of VDi is north slope(15.13?m and 30.36?m);LT on the robinia tree showed no significant difference between aspects(P>0.05),on the apricot tree was significantly higher in the north slope than in the south,east slope and slope top(P<0.05);LDMC on robinia was significantly higher on the north and west slopes than on the south,east,and slope tops(P<0.05),on the apricot tree is significantly higher on the north slope than on the south slope(P<0.05),The minimum appears at the top of the slope(0.246).LA and LWC of robinia and apricot have no obvious change rules.On the slope tops,LA and LWC of robinia and apricot both were the largest(9.21cm~2,26.41cm~2 and 64.88%,72.65%)?(3)The trade-off relationship of the two tree species is that:both robinia and apricot trees,the SLA significantly positively correlated with LWC and LA(P<0.05),and significantly negatively correlated with LDMC(P<0.05),in addition,LDMC and LWC were extremely significantly negatively correlated(P<0.01);On robinia,the VDi and VD showed a very significant negative correlation(P<0.01),LA with LDMC showed a significant negative correlation(P<0.01),with LWC showed a significant positive correlation(P<0.05);On apricot,VD and LA were significantly negatively correlated(P<0.05),VDi was significantly positively correlated with LT and LDMC(P<0.01),was significantly negatively correlated with SLA(P<0.05),in addition,LT and LDMC showed a significant positive correlation(P<0.01).(4)The change rule of soil factors with aspect(from south to east,west,and then north slope)is not obvious.With the increase of soil depth,SMC,pH,STP showed a decreasing trend,and SS,BD showed a increased;SWC was significantly negatively related to SS,BD and soil temperature(Tem)(P<0.05),and positively correlated with SOC(P<0.01);SS was extremely significantly negatively related to pH,and SOC(P<0.01).(5)Both robinia and apricot,The VD was significantly negatively correlated with SMC(P<0.01),positively correlated with Tem(P<0.01),negatively correlated with VDi and Tem(P<0.01),VDi was negatively correlated with Tem,SLA was positively correlated with Tem,and LDMC was negatively correlated with Tem(P<0.05).The VD of robinia was significantly positively correlated with SS(P<0.05),VDi was significantly positively correlated with SMC,SOC(P<0.05),and was significantly negatively correlated with SS(P<0.05),LA was significantly positively correlated with Tem(P<0.01),and SLA was significantly negatively correlated with BD(P<0.05).LT of apricot trees were significantly negatively correlated with Tem(P<0.01),while LA,SLA,LWC were significantly positively correlated with SMC(P<0.05).(6)Multiple regression analysis showed that the leading factors affecting VD,LA,LDMC of robinsia were Tem,the leading factors of VDi were Tem and SOC,and the leading factors of SLA were Tem and BD.Tem was the dominant factor of VDi,LT,SLA,LDMC in apricot trees,and SMC was the dominant factor affecting VD.It can be seen that the leaf traits of robinia and apricot have the most prominent response to Tem.