Research On The Anatomical Structure,Morphological Characters And Nutrients Of Fine Roots Of Pinus Dabeshanensis C.Y.cheng & Y.W.Law

The rare and endangered species Pinus dabeshanensis C.Y.Cheng & Y.W.Law has been studied since the 1980 s.In the past 40 years,the research on Pinus dabeshanensis is mainly based on its seed germination mechanism,population ecology and the perspective of genetic diversity to carry out scientific research.In addition,there are also preliminary studies on the branch and leaf stoichiometry of Pinus dabeshanensis.At present,most scholars have carried out multi-angle research on the relationship between the aboveground vegetative organs and reproductive organs such as leaves,branches and seeds of Pinus dabeshanensis and its endangered system from a macro perspective.However,few scholars have systematically studied the fine roots of Pinus dabeshanensis,trying to explain the relationship between the fine roots of Pinus dabeshanensis and the soil.The fine root is the most active unit in the transition between the aboveground and the underground of the plant,and plays a very important role in the nutrient absorption and transportation of the plant.The fine root plays an important role in the entire forest ecosystem.The morphological changes of fine roots will directly affect the absorption of nutrients in the underground soil by plant,and the morphological characteristics of fine roots can directly reflect the adaptability to the environment in plants.The changes in the morphological characteristics of fine roots have a very significant impact on the growth and development of plants,and are also a reflection of the changes in the functional traits of fine roots,which have become an important content of research in forest ecosystems.Therefore,this study took Pinus dabeshanensis in three forest lands in Miaodao Mountain National Forest Park,Yuexi County,Anhui Province as the research object,and the1～5 grade fine roots anatomical structure of Pinus dabeshanensis were measured,and the anatomical features of the fine roots of Pinus dabeshanensis(fine root diameter,fine root cortical thickness,fine root vascular bundle diameter,fine root Wi-root ratio)were obtained;at the same time the morphological characteristics of fine roots of grades 1～5 of Pinus dabeshanensis were also measured(the specific root length of fine roots,the specific root surface area of fine roots,and the specific root density of fine roots),and the carbon(C),nitrogen(N),and phosphorus(P)contents of Pinus dabeshanensis fine roots were measured.The differences among different characteristic parameters were compared and analyzed.The result shows:(1)There were significant differences in the anatomical structure of Pinus dabeshanensis fine roots at different root levels,and there were also significant differences in the anatomical structure of fine roots among different woodlands.The fine roots of grades 1～3 have a cortical structure and belong to the primary fine roots,which mainly undertake the absorption function;the fine roots of grades 4～5 have no cortical structure and belong to the secondary fine roots,which mainly undertake the function of transporting nutrients and water.Different grades of Pinus dabeshanensis fine roots bear different functions.(2)There were significant differences in the morphological characteristics of Pinus dabeshanensis fine roots at different root levels and among different woodlands,and the morphological characteristics of fine roots at different root levels would have an impact on their functional properties.The study found that the Pinus dabeshanensis fine roots have a smaller diameter and a smaller specific root surface area,and the fine roots have a stronger absorption function.(3)The elemental content of soil and Pinus dabeshanensis fine roots C,N,and P in three types of stands was lower compared with the national average,and the elemental content of fine roots C,N,and P was significantly affected by the nutrient content of soil.At the same time,the growth of Pinus dabeshanensis fine roots was limited by the N elements,and the nutrient content of fine roots depended largely on the level of soil nutrients.A comprehensive analysis of the anatomical characteristics,morphological characteristics of Pinus dabeshanensis fine roots and stoichiometry(C,N,P)in the three forest sites with the change pattern of fine root level indicated that there was variability in the function of Pinus dabeshanensis fine roots among different root levels,and N element would limit the growth and development of Pinus dabeshanensis fine roots.