an essay's abstract
Leaf Economic Traits Vary with Stand Age in Cunninghamia lanceolata
Abstract：There is a trade-off between the functional traits of plant leaves, and through the study of the economic characters of leaf functional traits, the dry weight investment-return rule of plant leaves can be explored. In this study, leaf dry matter content(LDMC), specific leaf area(SLA) and specific leaf mass(SLM) of cunninghamia lanceolata at different stand age were studied, and the differences of leaf functional traits and the relationship between traits in different developmental stages of Cunninghamia lanceolata were explored. During the 5-25 years development of Cunninghamia lanceolata, SLA first decrease and then rise, LDMC and SLM first rise and then drop, all at turning point of 10-15 years old. The 20 years old fir has the highest SLA, LDMC, and lowest SLM. It shows that the expected return of the unit leaf dry matter investment in the early stage of development is low, and the leaf dry matter of the unit leaf area is high invested. In the later stages of development, the reverse is the case. The growth rate of Cunninghamia lanceolata may be the highest in 20; The variation coefficients of LDMC in the 5-25 years old of Cunninghamia lanceolata were smaller than SLA and SLM. The variation coefficients of SLA and SLM of 5, 10 and 15 years old were higher than that of 20 and 25 years old and the variation coefficient of SLA of 5 years old is higher than that of other ages, and the SLM variation coefficient of 5 years old is second only to that of 20. It shows that the expected return and dry matter investment was more sensitive to the environment than metabolic activity and more sensitive in the young period. SLA is negatively correlated with LDMC, SLA is negatively correlated with SLM, SLM is positively correlated with LDMC. It shows that the more investment of dry matter, the lower metabolic activity of leaves, the lower activity of leaf, the lower expected return of investment, and the more investment of dry matter of leaves, the lower the expected return of investment of unit dry matter; The correlation between SLA and LDMC, SLM and LDMC is the strongest in 5 years. This shows that the metabolic activity is more closely related to the expected return and the investment in young fir; The regression coefficient between traits shows that the effect of metabolic activity on SLA is the largest in 5 years old, second in 20, dry matter investment has the biggest influence on metabolic activity and expected return in 20 years old (but except for the 5 years old, the models of LDMC with other traits of other ages are less fit).