Abstract:

【Objective】To understand the adaptation strategies and capabilities of grafted seedlings of different Alnus ledgeriana clones to the environment and select excellent clones for regional development, we investigated the biomass and allocation characteristics of one-year-old grafted seedlings of different clones of A. ledgeriana.【Method】The random block design method was used to divide the study site into three blocks, and each block contained 34 plots. Thirty-four dominant A. ledgeriana were collected from Xuanhan, Enyang and Jintang of Sichuan Province. The spikelets of dominant trees were grafted onto rootstocks with the same growth in November 2015. Approximately 100 rootstocks were grafted in each plot and repeated three times in different blocks. The plant heights and base diameters of all grafted seedlings in each plot were measured in mid-August 2016. Three average plants were selected as the study plants in each plot based on the heights and base diameters. We determined the biomass of each part of the study plants and then analyzed the differences in biomass and its allocation characteristics among different clones using ANOVA and systematic cluster analysis.【Result】The aboveground part of the fresh weight of the A. ledgeriana clones was ranked as leaf > trunk > lateral branch, and the relative water content of each part was more than 50%. The leaf and trunk were the heaviest parts of the aboveground biomass, and the lateral branch was the lightest part. The underground part of the biomass was ranked as rough root > fine root > medium root. Cluster analysis showed that the 34 A. ledgeriana clonal seedlings were divided into three categories. The second category of clonal seedlings had the largest total biomass, then the first category, and the third category was the smallest. The biomass allocation characteristics of the three categories of clonal seedlings were also different. The ratios of the biomass of lateral branches and fine roots in the second category of clonal seedlings were larger than those in the first and third categories. The ratios of the biomass of lateral branches and trunks in the first category clonal seedlings were relatively high, while those of leaves and fine roots in the first category clonal seedlings were lower than those in the second and third categories. The ratio of the biomass of leaves in the third category clonal seedlings was greater than that in the first and second categories, the ratios of the biomass of lateral branches and trunks in the third category clonal seedlings were lower than those in the first and second categories, and the ratio of the biomass of rough roots in the third category clonal seedlings was the largest.【Conclusion】The biomass and allocation characteristics of different one-year-old A. ledgeriana clones were distinct. Among them, the total biomass of the second category clonal seedlings was the largest and their allocation characteristics were evenly distributed, supporting that the second category clonal seedlings may have the strongest adaptability to light and soil hydrothermal conditions. The total biomass of the first category clonal seedlings suggest that they may have relatively strong adaptability to light conditions but relatively poor adaptability to soil hydrothermal conditions. The total biomass of the second category of clonal seedlings was the lowest, indicating that they may have the weakest adaptability to the environment.

Key words: Alnus ledgeriana, clone, biomass, branch, leaf, root, biomass allocation, cluster analysis