Latitude Mechanism And Influence Factors Of Leaf Traits Of Metasequoia Glyptostroboides In Eastern Coastal China

Leaf traits(morphological traits,stoichiometry)are sensitive to environmental changes in the process of evolution and may vary with changes in environment.So,the study to analyse the rules of plant leaf traits change with latitude gradient and the relation to enviroment change in the context of climate and soil changes has important theoretical significance.Metasequoia glyptostroboides is one of the main tree species in shelterbelts in eastern coastal China and the most widely distributed trees,stretching from temperate to subtropical zone,which provides natural laboratories to examine the effects of environmental factors on leaf traits of single species at latitudinal scale.In this study,we collected green and senesced leaves of M.glyptostroboides trees with similar age and soil samples based on eight stands growing along different latitude in the coastal areas of eastern China.We recorded the climatic and geographical factors,and we tested the rules of latitude gradient in leaf morphological traits(for example,leaf length,leaf width,leaf perimeter,leaf area,ratio of leaf length to width,specific leaf area(SLA),and leaf dry mass),stoichiometry and nutrient resorption and its relation to environmental changes.The main results are concluded as follows:1.The leaf morphology traits variation of M.glyptostroboides within the population less than the variation among the population.The coefficient of variation of leaf length,leaf width,leaf perimeter and leaf dry mass are 70.60%,80.53%,63.27%and 62.89%,respectively.2.Leaf length,leaf width and leaf perimeter increased with latitude rising,while the leaf area and SLA firstly increased and then decreased.The mean annual temperature and annual precipitation were major environmental factors of the leaf traits along latitude gradient.With soil N increasing,SLA firstly decreased and then increased,and leaf mass significantly decreased.But for soil P,with it increased,SLA increased,and leaf mass significantly decreased.3.Green leaf N and P concentrations in M.glyptostroboides were 25.04 and 1.75 mg·g-1,respectively,and were positively correlated with latitude,while N:P ratio did not show a clear trend with latitude.N resorption efficiency and P resorption efficiency were 45.65 and 55.30%,respectively.N resorption efficiency was significantly related to latitude,and P resorption efficiency first increased and then decreased along the increased latitude.The mean annual temperature and mean annual precipitation were the major environmental factors affecting green leaf stoichiometry,and nutrient resorption efficiency,there was a weak relationship between soil and stoichiometry,nutrient resorption efficiency.4.On the latitude gradient,M.glyptostroboides leaf length,leaf width increased with N stoichiometry rising,while SLA firstly increased and then decreased.Leaf length,leaf width and leaf perimeter increased with P stoichiometry rising.