Study On Leaf Economic Spectrum Of Several Typical Deciduous Oaks(Quercus)in China

As the most important producer in the ecosystem,plants play a vital role in the ecosystem.Leaf is the foundation of terrestrial ecosystem functions,and the resource balance between leaf traits is the core idea of "leaf economic spectrum".Deciduous oak is the most typical representative tree species in warm temperate deciduous broad-leaved forest.It has a wide distribution range and has ecological characteristics of drought tolerance and barren tolerance.It plays an important role in soil improvement,vegetation restoration and soil and water conservation.In this study,the five typical deciduous oak plants Quercus acutissima,Quercus variabilis,Quercus aliena,Quercus Jabri,Quercus serrata var.brevipetiolata were taken as the research objects,and the leaf economic spectrum of the deciduous oaks was explored by a combination of field experiments and greenhouse control.The main results are as follows(1)Different deciduous oak plants have significant differences among most of the leaf traits,and the leaf traits are generally correlated and show a significant linear relationship.Deciduous oaks have significant differences in leaf nitrogen content and leaf phosphorus content,and there are slight differences between leaf nitrogen content,leaf phosphorus content,leaf length to width ratio,specific leaf weight and leaf area Leaf nitrogen content was positively correlated with leaf phosphorus content,leaf area and leaf phosphorus content,specific leaf weight and nitrogen phosphorus ratio,and specific leaf weight was negatively correlated with leaf phosphorus content,leaf area and leaf nitrogen phosphorus ratio(2)There are also resource trade-off strategies among the five deciduous oak species.The position of Q.variabilis in the leaf economic spectrum is more biased towards the low leaf nitrogen and phosphorus content and the large weight of the leaf.It is a "slow investment-return" type species.(3)The correlation between leaf economic spectrum traits and longitude and latitude is more significant,and most leaf traits are significantly correlated with topographic factors.The leaf nitrogen content and the ratio of leaf nitrogen to phosphorus in Shandong region are obviously higher than those in southwest region;the leaf phosphorus content in southwest area is obviously higher than that in Shandong region.(4)On the small scale,the correlation between leaf characteristics and environmental indicators is not as obvious as on the large scale.In southwest region,only Q.acutissima leaf phosphorus content is correlated with aspect and slope.In Shandong region,only Q.variabilis had correlations between altitude and leaf nitrogen to phosphorus ratio,slope to leaf phosphorus content,slope to leaf length to width ratio(5)Whether under single-factor or double-factor control,it will have a certain effect on leaf traits under different treatments,among which the effect on leaf nitrogen content is significant and shows differences.Under manual control,the leaf traits of Q variabilis seedlings still have correlations and are generally consistent with the correlation of leaf traits under natural conditions.Leaf phosphorus content was significantly positively correlated with leaf length to width ratio;leaf area was significantly negatively correlated with specific leaf weight.This study uses the leaf economic spectrum idea to reveal the resource trade-off strategy of leaf traits of different deciduous oak plants and the response mechanism of leaf function traits to the environment.The research in this experiment aims to supplement and improve the leaf economic spectrum of the oak in the warm temperate zone,which is of great significance for promoting the restoration,protection and utilization of oak forests.It also has reference significance for other similar types of community ecosystems.