Abstract: Fine roots are important for the function of individual plants. To better reveal the fine root strategy of bamboo expansion, we explored its plasticity in the process of Phyllostachys edulis expanding into Chinese fir forest. We compared the functional traits of fine roots of moso bamboo in different stages and explored the morphological plasticity when it expanded into Chinese fir forest. The fine root biomass (FRB), root length density (RLD), specific root length (SRL), key nutrient contents and their ratios were measured. The results showed that the FRB and RLD increased with moso bamboo expansion. The SRL and the content of N and P decreased with moso bamboo expansion. The FRB and RLD at final expansion stage were 7.03 times and 1.57 times of that at the initial expansion stage. The FRB and RLD at final expansion stage were 1683.04±188.17 g·m² and 6483.14±846.82 m·m^-3, respectively. The SRL decreased from 2.61±0.20 m·g^-1 at initial expansion stage to 0.70±0.06 m·g^-1 at the final expansion stage, with the former being 3.73 times that of latter. The N content decreased by 41.11%, from 5.06 g·kg^-1 at initial expansion stage to 2.98 g·kg^-1 at the final expansion stage. The P content decreased by 43.33%, from 0.30 g·kg^-1 at initial expansion stage to 0.17 g·kg^-1 at final expansion stage. There were significant correlations between N, P, K contents, C∶N and the FRB and SRL, indicating that the morphological traits and nutrient contents of fine roots varied with environmental changes and that the fine roots of moso bamboo had higher plasticity. The moso bamboo can grow quickly and use soil resources efficiently in new environment by increasing the SRL and N and P contents.

Key words: peanut cultivar, pod-setting stage, drought stress, drought resistance, physiological trait.