Differences Of Seed Nutrient Contents, Seedling Growth And Cold Tolerance In Different Families Of Styrax Tonkinensis

Styrax tonkinensis, also known as Vietnam benzion and white blooms, is a deciduous light-requiring tree belonging to Styracaceae. In recent years it has been recognized as worthy of fast-growing forest planting new trees and it's also an excellent source of biomass species. In the past years a lot of researches have been conducted on biological characteristics, reproduction, afforestation technology, physiological characteristics of Styrax tonkinensis, but studies on breeding and other aspects haven't been done systematically. This paper selected the best pedigree of Styrax tonkinensis from 40 different pedigrees in JiShui county JiangXi province by comparing the seed nutrient contents, seedling growth and cold resistance in different families. The main conclusions are as follows.1. By comparing and measuring the weight of one thousand of seeds and the content of nutrients of the 40 different pedigrees of Styrax tonkinensis, it is found that the fatty acid content is between 55 percent and 62 percent, it's a high oil content species and the soluble sugar content is also high which can be up to 90.87mg/g. Through correlation analysis, there is a significant negative correlation between seed weight, soluble sugar content and fatty acid content. According to fatty acid content, 10 pedigrees were shortlisted the fatty acid content of which are higher than the average.2. From the research of one year old seedling's growth characteristics, it is studied that the height is from 66 to 95 centimeter, the diameter is between 11 and 19 millimeter, biomass is between 27 and 146 gram, it's a large difference. By studying nutrients content and growth characteristics of one year old seedlings, it is concluded that there is a very significant positive correlation between seed weight, content of soluble sugar and height, diameter, biomass of seed. According to membership function analysis, 10 pedigrees were shortlisted the growth characteristics of which is excellent.3. In the comparing of two years old seedling's growth characteristics, the height of seedlings is between 120 and 175 centimeter and the diameter is between 17 and 25 millimeter,biomass is between 112 and 415 gram, shows a large difference. So the biomass is an important indicator to evaluate the seedling quality. Through the growth characteristics correlation analysis of one year old and two years old seedlings, there is a significant positive correlation between them. According to membership function analysis of two years old seedling's growth characteristics, 10 pedigrees were shortlisted the growth characteristics of which is excellent.4. Under the winter low temperature stress, the content of corresponding physiological substances in different pedigrees of Styrax tonkinensis is different and branches electrolyte penetration is between 14 percent and 76 percent, indicating that with same temperature conditions different pedigrees of seedling hurt quite different. Cold resistance osmolytes proline and malondialdehyde content are separately 0.03ug/g DW to 0.56ug/g DW and 1.48ug/g DW to 12.23ug/g DW indicating the large difference of cold resistance among different pedigrees of Styrax tonkinensis. Total nitrogen content in the branches distributes between 1.26% and 3.76%. Through principal component analysis, biomass, root volume, conductivity, malondialdehyde, total nitrogen, proline, soluble protein content of seedling have a close relationship with cold resistance, and can be used as main indicators in seedling cold tolerance evaluation of Styrax tonkinensis.