Effects Of Litter On The Early Regeneration Of Pinus Densata Forest Seedlings In Sejila

In this study,the seeds of five Pinus densatas communities in Sejila Mountain were selected as the research objects,and the seed characteristics of Pinus densatas in Sejila Mountain,the effects of water extract of Pinus densatas litter on Seed Germination and seedling growth,the relationship between litter cover thickness and early regeneration of Pinus densatas seeds,and the effects of different forest sowing methods on early regeneration of Pinus densatas seedlings were studied The purpose of this study is to solve the problems of natural regeneration and artificial forest obstacles of Pinus densatas in Southeast Tibet,enrich the research of near mature forest and artificial forest regeneration,and provide scientific theoretical basis for maintaining the health of forest ecosystem and the conservation and stable development of Pinus densatas artificial forest.The main results are as following(1)The results showed that the variation of cone size was relatively stable in the five regions of Sejila Mountain,and the core characters of P.consciences were in accordance with the normal distribution(Sig>0.05).The results of one-way ANOVA showed that the average values of cone length,cone width and cone fresh weight of clinician plot in Linzhi town were the largest among the five sample points,which indicated that there was a positive correlation between cone weight and cone size of Alpine pine.Meanwhile,it was found that the maximum cone length and the maximum seed scale number appeared in harangue sample point in Bayi District,and the minimum cone length and the minimum seed scale number appeared in birchen mountain sample point Therefore,it is speculated that there is a positive correlation between cone size and seed scale number.(2)There were considerable differences among seed characters of Pinus density,and the seed length of clinician plot in Linzhi Town,which had the largest cones,was also the largest,indicating that there was a correlation between the two.However,there was not any significant correlation between the three indexes of seed width,seed wing length and100 seed weight and cone size and seed size.On the whole,phenotypic traits of Pinus tournaments seed in clinician sample site of Linzhi town were better.Due to the difference of the geographical environment,seed traits of Pinus tournaments evolved in a definite direction in the long-term natural selection process,which led to the change of character distribution.(3)In the experiment of Pinus almandine litter extract,the germination rate of all the control groups was the highest in the Middle East Judicial site,and the lowest in the kid-glove site.In all treatments,the germination rate of seeds in cartilage was the highest under the treatment of 5% concentration,and the all elomorphic promoting response index of germination index reached 0.30,which was a moderate promoting role.In this experiment,5% concentration of litter water extracts had the best effect on the immediate regeneration of seed in cartilage.The results showed that the germination index,seedling growth index and seedling biomass index of doughtiest and harangue samples showed inhibition effect under different concentrations.Seed of Danniang sample was atypical,and the germination rate,growth and biomass showed the trend of inhibition first and then promotion.The germination rate and biomass of clinician gradually built up over the increase of water extracts concentration,and the germination rate and biomass rose by 25%the results showed that the allelomorphic index of the concentration treatment was promotion and happened to the maximum value.(4)The results showed that: under the condition of litter coverage,the smaller the coverage,the higher the survival rate of seedlings;under the condition of shallow(1 cm,2 cm)coverage,the survival rate of Dongjiuqiao,belligerence and Danniang township was better;under the condition of deep(3 cm,4 cm),the survival rate of seedlings was higher The survival rate of all sites was not good under the litter cover.There was significant difference between different litter cover thickness and different sites(P<0.05),but there was no significant difference in seedling diameter,needle length and basal diameter among different sites,which indicated that the growth height of above ground part of surviving seedlings was not affected by litter thickness,but there was significant difference between seedling needle length and seeds at different sites(P<0.05).In general,with the increase of litter cover thickness,the root biomass,diameter biomass,leaf biomass and total biomass of the other four plots were promoted by shallow mulching(1 cm,2 cm)and inhibited by deep mulching(3 cm,4 cm),except for those of BK plot.(5)The results showed that the seed survival rate of the control group was the lowest,which was significantly lower than other treatments.The highest survival rate of different sowing methods was the treatment of clearing herbs and litter(retaining shrubs),which was 7.8times of the control group.There were significant differences in root length,diameter length,needle leaf length and base diameter of seedlings among different sites with different sowing methods(P<0.05).Except for needle leaf length,there were not any meaningful differences between the other three indexes and the sample sites.That is to say,under the same sowing method,the change range of indexes among different sites was smaller,and the root length grew best under the treatment of retaining shrubs,Dongjiuqiao,belligerence and Danniang The results showed that had obvious promoting effect.There were considerable differences in root biomass,diameter biomass,leaf biomass and total biomass of the change of sowing methods(P<0.05).In general,the growth of root biomass in E treatment was the best thing,and the growth of the three biomass indexes in the remaining sites was the best under the retaining shrub treatment.