Response of leaf functional traits of Moso bamboo during the invading process into the broad-leaved forest

As a clonal plant, Moso bamboo can invade surrounding forests; however, little information on the leaf functional traits of the species during the invading process is known. In this study, we examined dry matter content (LDMC), carbon content (C) and stoichiometric ratios of leaves among four forest types(type 1: pure bamboo forest, type 2:bamboo-dominated mixed forest, type 3: broad-leaved trees-dominated mixed forest, and type 4: nearly pure broad-leaved forest)as well as at differentculm age classes (Ⅰ,Ⅱ, Ⅲ and Ⅳ).The LDMC, C and N∶P ratios were significantly different among the four forest types; the LDMC in type 2 was significantly higher than that in type 4, the C in type 1 was significantly lower than that in types 3 and 4, and N:P ratios in types 1 and 2 were higher than those in types 3 and 4. No significant differences were found for specific leaf area (SLA), leaf nitrogen content (N), leaf phosphours content (P) and leaf N:P ratio among the four types. These results demonstrated that Moso bamboo has taken adaptive measuresto different habitats.With regard to the culm age, the SLA and LDMC were significantly different among the four culm age classes in type 1; for instance, both in class I differed remarkably from that in Ⅲ and Ⅳ, respectively. In type 2, the C, N and C∶N ratio showed remarkable differences among the age classes, while N∶P ratios were different in types 1-3, having the lowest in class Ⅱ, followed by class Ⅰ. These findings indicated that the leaf functional traits caused by culm age was more distinct compared with other three forest types.The inconsistency of age effect was most likely caused by the stronger environmental influences,which counteracted the variation in growing culm with different ages in types 2-4. Bivariate correlations indicated that SLA correlated significantly negatively with LDMC, but positively with C, N and P, while LDMC showed opposite relationships with C, N and P, respectively;N was positively correlated with P. When SLA and LDMC changed, the most notable variation occurred in C, followed by N, and least in P, suggesting that the stoichiometric ratios (tradeoff) of leaf functional traits of Moso bamboo has presented adaptive adjustment during the invading process.