In order to make clear the relationships between photosynthesis and leaf N, leaf P and SLA of tropical trees, and test the differences in the relationships among life-form groups (trees, shrub-like trees and shrubs), seedlings and saplings of 101 species from a tropical montane rain forest, located in the Diaoluo Mountain of Hainan Island, were selected. The net photosynthesis based on area and mass (A area and A mass), leaf nitrogen content based on area and mass (N area and N mass), leaf phosphorus content based on area and mass (P area and P mass) and specific leaf area (SLA) were measured and/or calculated. The results showed that A area and A mass tended to follow the order of shrubs > trees > shrub-like trees. One-way ANOVA showed that the difference in A area between shrubs and shrub-like trees was significant (p<0.05), and for A mass there were significant differences between shrubs and shrub-like trees and between shrubs and tree species (p<0.05). The relationships between A area and N mass were highly significant in all three life-form groups and for all species (p<0.0001). The correlation between A area and P mass was highly 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 area and SLAwas highly significant in shrubs (p = 0.0006), trees (p<0.0001) and for all species (p<0.0001), however this relation was not significant in shrub-like trees (p>0.05). The relationships between A mass and leaf N and SLA were highly significant in all three life-form groups and for all species (p<0.0001). For A mass and leaf P, there were significant correlations in tree groups (p = 0.0377) and highly significant correlations in shrub groups (p = 0.0004), shrub-like tree groups (p = 0.0018) and for all species (p < 0.0001). Stepwise regression showed that predicted A mass values were closer to the observed values than those for predicted A area values. Thus, it can be concluded that the relationships obtained from seedling and sapling measurements are close to those from mature individuals; correlations between photosynthesis and N mass, P mass and SLA traits are significant and the relationships are stronger and more stable for A mass than for A area.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics