| Toona ciliata var.pubescens belongs to Toona genus Meliaceae,and has economic values and bright prospect for development.Due to the following two factors: the long-term over exploitation of T.ciliata var.pubescens forest resources,and slow progress of natural regeneration of natural population,the number of the distribution area is decreasing.Facing the endangered situation,it is listed as the national secondary protection of endangered species,according to the book: China Plant Red Data.Light quality,one of the most important factors limiting the natural regeneration of forest,is the basic element for plant growth and development.Light quality regulates the growth and development of plants.The suitable light composition is not only beneficial to the accumulation of carbohydrate,but also can enhance the resistance of plants to the environment.In this paper,the seed of T.ciliata var.pubescens was collected from Guanshan National Nature Reserve and Jiulianshan National Nature Reserve as experimental materials in November 2015,carried experiments of light quality treatment by covering different colors of PVC film,observed seedling height,caliper,biomass allocation,leaf morphology and chlorophyll fluorescence parameters,and analyzed difference on the conditions of providing different light quality and provenances.All the experiments that the writer did is to clarify the mechanism and effect of light quality factors on T.ciliata var.pubescens seedling growth and to provide theoretical basis for natural regeneration disorder.The results show:Light quality is significant to the growth of T.ciliata var.pubescens,such as its seedling height,caliper,biomass,root / shoot ratio,leaf area,rachis,fluorescence parameters and chlorophyll content of annual seedlings;compared with the control group,the treatment showed a different degree of light suppression phenomenon,and the degree of light suppression showed : Red < Blue < Green < Yellow.Treated under Red light,seedling high growth was higher than the control group,and other treatment were light suppression phenomenon;rough growth of the treatment were light suppression phenomenon.Biomass of various parts under control processing was optimal.The degree of light suppression phenomenon would be different under the treatment.Yellow and Green light suppressions were the most.But by increasing the root and shoot ratio,the degree of light suppression could be alleviated.Leaf area and rachis length under the control group were the best,then followed by the Red and Blue.In all of these experiments,there was no significant difference in roundness and leaflets.Chlorophyll content and fluorescence parameters in the Blue shed the best treatment.Under the different light quality treatments,all the indexes showed that the provenances of Jiulianshan were better than those of Guanshan.and the Jiulianshan.In the light suppression environment such as Green and Yellow,its growth of light suppression is weaker than that of Guanshan.Through the analysis of the main components of seedling height,caliper,leaf morphology,biomass,chlorophyll content and fluorescence parameters,the total contribution rate of the first two principal components was 60.27%.The contribution rate of seedling height,caliper,leaf morphology and biomass to principal component 1 was 47.66%,and the indicators were positively correlated;the contribution rate of chlorophyll content and fluorescence parameters to principal component 2 was 12.61%,but the correlation was not significant.Conclusion: covering the film,which was to simulate the light quality conditions,not only changed the light composition,but also caused a certain light suppression phenomenon.This test,to some degree,simulates the natural forest light quality environment.And this test shows that the whole light is more favorable for seedling growth and regeneration and the light environment in natural communities is one of the elements that suppresses natural regeneration barriers. |
PDF Full Text Request