海南岛热带山地雨林幼苗幼树光合与叶氮、叶磷及比叶面积的关系

Photosynthesis in relation to leaf nitrogen,phosphorus and specific leaf area of seedlings and saplings in tropical montane rain forest of Hainan Island,South China

以海南岛吊罗山热带山地雨林101个物种的幼苗幼树为试验材料,测定其光合、叶片氮、磷含量及比叶面积;检验其相关关系,并按乔木,乔灌木(小乔木至大灌木)和灌木3个生活型组进行分组检验。研究结果表明,单位叶面积(Aarea)和单位叶重量的光合速率(Amass)均表现出灌木>乔木>乔灌木,方差分析表明,灌木和乔灌木之间Aarea差异显著;灌木和乔木以及灌木和乔灌木之间Amass差异显著(p<0.05)。Aarea与叶氮含量之间的相关性在不同生态型组和所有物种之间均达到极显著水平(p<0.0001);与叶磷之间的相关关系在灌木(p=0.0038),乔灌木(p=0.0002)以及所有物种(p<0.0001)之间达到极显著水平,但是在乔木中未达到显著水平(p>0.05);与SLA之间在灌木(p=0.0006)、乔木(p<0.0001)和所有物种(p<0.0001)之间达到极显著水平,但是在乔灌木中未达到显著水平(p>0.05)。Amass与叶片氮含量、SLA的相关关系在不同生活型组和所有物种中都达到极显著水平(p<0.0001);与叶磷含量之间的相关性在灌木(p=0.0004),乔灌木(p=0.0018)及所有物种(p<0.0001)中极显著,在乔木生活型组中也达显著水平(p=0.0377)。逐步回归表明,与Aarea相比,Amass估计结果更接近于实际测值。由此可见,海南岛热带山地雨林林下幼苗幼树的光合和叶氮、磷含量及SLA之间相关关系与基于成树的研究非常相似,并且A比A更能稳定体现这种相关性。

In order to clear the relationships between photosynthesis and leaf N, leaf P, SLA of tropical trees and test the differences of relationships among life-form groups （tree, shrub-like tree and shrub） , seedling and saplings of 101 species in tropical montane rain forest located in Diaoluo Mountain of Hainan Island were selected. The net photosynthesis based on area and mass （Aarea and Amass ）, leaf nitrogen content based on area and mass （ Narea and Nmass ）, leaf phosphorus content based on area and mass （Parea and Pmass ） and specific leaf area （SLA） were measured and calculated. The results showed that Aarea and Amass, tended to be of shrub 〉 tree 〉 shrub-like tree. The one-way ANOVA showed that Aarea between shrub and shrub-like trees was significantly different （p 〈 0.05 ）, and for A there were significant differences between shrub andshrub-like trees, and shrub and tree species （p 〈0.05）. The relationships between A area and Nmass were most significant）n all three life form groups and for all species （p 〈 0. 0001 ） ; the correlation between Aarea and Pmass was most significant in shrubs （p =0.0038）, shrub-like trees （p =0. 0002） and for all species （p 〈0. 0001 ）, but not significant in trees （p 〉 0. 05） ; The relationship between A a and SLA was most significant in shrubs （p =0. 0006） , trees （p 〈0. 0001 ） and for all species （p 〈0.0001 ）, however not significant in shrub-like trees （p 〉0.05）. The relationships between A and leaf N, SLA were most significant in all three life form groups and for all species （p 〈0. 0001 ） ; on Amass vs. leaf P, there were significant correlations in tree group （p = 0. 0377 ） and most significant correlation in shrub group （p = 0. 0004）, shrublike tree group （p =0. 0018） and for all species （p 〈0. 0001 ）. Stepwise regression showed that the predicted Amass values were closer to the observed values than the predicted Aarea values. Thus, it could be concluded that the relationships got from seedling and sapling measurement is close to those from mature individuals; the correlations between photosynthesis and the traits of Narea, Pmass and SLA are significant, and the relationships are stronger and more stable for Amass than for Aarea.