Researches On Germinating Mechanism Of The Constructive Species Of Subalpine In Western Sichuan

The high mountain area of western Sichuan is the main body of the upper reaches and the Yangtze River,which is the second largest forest area in China.Since the 1950s,the virgin forests with Picea asperata and Abies faxoniana as the main dominant groups have suffered from large-scale deforestation,forest coverage has fallen sharply,and ecosystem functions have deteriorated.At the same time,the special ecological environment in the alpine region is superimposed with human disturbance and global changes,and it is urgent to strengthen the restoration and restoration of alpine subalpine degraded forest vegetation.In this study,we explored the restriction mechanism of seed germination of four colony species in the Miyaluo region,combined with field sowing experiments,and explored the most suitable seeding measures for seed germination under artificial breeding,aiming to plant seeds for the wild seeding in the Miyaluo region.Provide theoretical and technical support.There are four main contents in this study.Collect seeds of four main tree species,observe the size of the cones and the size of the seeds,explore the optimal germination conditions of the seeds,and explore the field experiments of different treatments on seed growth.The following work has been done according to the experimental design.?1?From September to October 2017,we collected 4 groups cone in Aba Prefecture,and measured the cones and seeds trait.?2?From November 2017 to July 2018,through indoor experiments,explore the effects of temperature,light,hormones and other conditions on the germination of four different species of seeds;?3?In May 2018,according to different experimental designs,the field planting experiment of the Miyaluo plot was carried out,and the environment of the plot was monitored.The results are as follows:?1?In this experiment,The optimum temperature for seed germination of Larix mastersianawas 25/20?,and the germination rate was 47.33%;The optimum temperature for seed germination of Picea asperata was 25/20?,and the germination rate was 84.67%;The optimum temperature for seed germination of Betula albosinensis rate was 25/10?,and the germination rate was 25.33%;the optimum germination temperature for Abies faxoniana seeds was 25/15?,and the germination rate was 50.67%;?2?Light conditions can affect the germination rate of Picea asperata,Betula albosinensis and Abies faxoniana seeds.The germination rate is characterized by:semi-light and semi-dark>full light>full darkness;the germination rate of Betula albosinensis has no difference under light treatment;The addition of exogenous hormones and nutrients has a certain promoting effect on seed germination.500 mg/L GA₃+bacterial fertilizer has a significant effect on the elongation of Picea asperata seed roots;?3?When planted in the field,the traits of the species determine their germination rate.The order of seed germination rate of each species is:Picea asperata>Larix mastersiana>Abies faxoniana>Betula albosinensis.The survival rate of coniferous/broad-leaved mixed sowing was higher than that of pure sowing.2×2 m sowing density has higher preservation rate than 1×1 m sowing density;water-retaining agent+fertilization method can improve seed germination rate in summer;The germination rate of Picea asperata was significantly higher than that of the other three species.The germination rate of Picea asperata at different densities was bare land>close irrigation>sparse irrigation;Abies faxoniana and Larix mastersiana has the highest germination rate in dense irrigation.The long-term effect of seeding density on seed preservation rate needs further verification.In summary,this study found that different species have different germination characteristics.When planting in the wild,different human seeding measures have a certain impact on seed preservation rate.In the future,further research should be conducted on the different seeding methods of different species,such as the depth of burial,the heat preservation of seedlings,and the effects of soil animals on seedling growth.