Effect Of Gap On Growth,Morphology And Nutrient Of Transplanted Quercus Mongolica And Fraxinus Mandschurica Saplings

The formation of the gap changed the heterogeneity of the gap,resulting in a difference in plant regeneration.In our study,we used the natural forest of Quercus mongolica(15 years old),Fraxinus mandschurica(9 years old)artificial regeneration saplings in the Changbai Mountain area of Songjianghe as the research object,to explore the effect of gap size of two species growth,morphology and nutrient status,It also made us to understand the long-term effect of gap and reveal the different size gaps in two species differences in morphology and growth,nutrient metabolism and adaptation to the environment strategy.It also can provide a theoretical basis for the artificial regeneration.The results show that:(1)The height,diameter,crown length and crown width of Q.mongolica and F.mandschurica saplings were significantly decreased with decreasing gap size(P<0.05).The length and collar diameter of first-order-branch were significantly decreased with decreasing gap size of tree species(P<0.05),while density of first-order-branch and the branch angle were increased.The leaf length,leaf width,average leaf area and leaf area index of tree species decreased with decreasing gap size.However,the specific leaf area decreased at first,followed by an increase with decreasing gap size.With the decrease of gap size,total biomass were significantly decreased(P<0.05),the root-shoot ratio of Q.mongolica saplings gradually decreased,while the root-shoot ratio of F.mandschurica saplings decreased at first and then increased.(2)The contentration of C,N,P and K of Q.mongolica and F.mandschurica saplings were significantly different among organs(P<0.05),which were larger in leaves,roots and branches,but smaller in stem(P<0.05).The gap size significantly affected Q.mongolica saplings P content in leaves,N and P contents in stem and P and K contents in roots(P<0.05),which was significantly higher in UC(under canopy)(P<0.05).The gap size has significant influenced on the C and N content in leaves,N and K content in branches and P content in stem of F.mandschurica saplings(P <0.05),the contentration of C in leaves has significantly different in LG(large gap)(P<0.05),the contentration of N in leaves and N,K in stem were has significantly different in UC(under canopy).(3)The contentration of NSC and its components of Q.mongolica and F.mandschurica saplings were significantly different among organs(P<0.05),the concentration of soluble sugar in leaves and branches were larger than in stem and roots(P<0.05).The gap size significantly affected the contentration of NSC and its components of tree species(P<0.05).The contentration of NSC and its components in leaves,branches decreased with decreasing gap size(P<0.05),while the contentration in stem and roots were significantly increased with decreasing gap size(P<0.05).(4)The contentration of C,N,NSC and NSC of Q.mongolica and F.mandschurica saplings had no significant difference in different gap(P>0.05).The contentration of C was increase with root order,the contentration of N was decreased significant with root order(P<0.05)and the contentration of NSC and its components of tree species increased significantly with with root order(P<0.05).(5)The stoichiometry of Q.mongolica and F.mandschurica saplings were significantly different among organs(P<0.05),which were larger in roots and stem,and smaller in leaves and roots(P<0.05).The stoichiometric of tree species were significantly different with decreasing gap size(P<0.05).The stoichiometric in leaves and branches were larger in gaps(P<0.05).The stoichiometric of Q.mongolica saplings in roots was larger in gaps,while F.mandschurica was instead.