Effects of truncation intensity on the biomass allocation and physiological characteristics of Dendrocalamus latiflorus

The effects of three different truncation treatments, i.e., light, medium and heavy truncation treatments on biomass allocation, current-year twig indexes, and quantity of commodity lea-ves, net photosynthetic rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and leaf water potential (LWP) values of Dendrocalamus latiflorus were studied, and the adaptation mechanisms and survival strategy of D. latiflorus under these silvicultural truncation treatments were discussed. Results showed that the biomass of D. latiflorus and its allocation rates were significantly affected by truncation treatments, compared with the untruncated control. Leaf to branch, leaf to stem, and branch to stem biomass ratios under all truncation treatments were significantly higher than under the untruncated control. The diameter, number, and length of current-year twigs, and the quantity of commodity leaves in light truncation and medium truncation treatments were markedly higher than in the control, and were increased by 43.0%, 53.3%, 29.8% and 39.5%, respectively, in medium truncation treatment compared with the control. After truncation treatments, the overall trend of the physiological characteristics of D. latiflorus, including Pn, Tr, WUE, LWP values, were displayed in the order of the peak stage > the telophase stage > the initial stage. The Pn, Tr and WUE values of D. latiflorus were significantly improved in the truncation treatments. The Pn va-lues were greatest in the medium truncation treatment followed by the light truncation treatment, heavy truncation treatment, and were the lowest in the control at the peak and telophase stages. At the peak and telophase stage the Pn values in the medium truncation treatment were 1.4 and 1.3 times as much as the control. The Tr values at the initial, peak and telophase stages were the greatest in the heavy truncation treatment, followed by the middle truncation treatment and the light truncation treatment, and were the lowest in the control. In this study, the medium truncation treatment showed a significant advantage in improving plant biomass allocation, quantity of commodity leaves, and other physiological indices, and could effectively improve the ability of moisture acquisition for D. latiflorus.