The Variability Of The First-order Root Functional Traits Of Main Woody Plants In Three Plots In Northeast China

In the forest ecosystem,fine roots have a large and complex branching system,especially the first-order roots with an absorption function,which plays an important role in nutrient and water absorption.When external environment changed,what kind of survival strategies are made by the first-order root,which can reveal the driving factors that cause changes in the pattern of vegetation distribution on different regional scales,and explore the relationship between plants and the environment.Therefore,this study selected the main woody plants in the three regions of Fairy Cave,Changbai Mountain and Maoer Mountain in Northeast China as the research object.It revealed ecological mechanism of woody plants and adaptati on mechanism to environmental changes by exploring the morphological characteristics and chemical composition of the first-order roots.The study found:(1)There is a significant difference in the characteristics of the first-order root traits among different woody plants,as : mean specific root length of the first-order root of Acer ginnala in the Xianren Cave is the biggest(268 m?g-1),but Fraxinus mandschurica is the opposite(35.3 m?g-1).There was a good correlation between the functional traits of the first-order root.There was a significant positive correlation between root length and diameter,nitrogen content,and carbon content.Root length was significantly negatively correlated with specifical root length and branch strength;and diameter was significantly negatively correlated with specifical root length and branch strength.There is a significant positive correlation between specifical root length and branch strength.(2)With the change of Fairy Cave-Changbai Mountain-Maoer Mountain,the length,diameter,and surface area of each plot showed a trend of decreasing first and then increasing.The difference was significant.The average length,diameter,and surface area of the first-order root of the Fairy Cave is the largest,followed by Maoer Mountains and Changbai Mountains,as: the average root length of the three plots is 4.6 mm,3.4 mm,and 4.0 mm;The average diameter of the three places is 1.2 mm,0.8 mm,and 1.1 mm,respectively.(3)With the change of Fairy Cave-Changbai Mountain-Maoer Mountain,the mean weight of the first-order roots showed a downward trend.The average weight of the three plots was 5.3 mg,4.3 mg,and 3.0 mg,respectively;the root length and branch strength were opposite,showing an increasing trend,and were in three plots.The difference between the three plots was significant in the weight,root length,and branch strength of the first-order roots.(4)There was no significant difference between Fairy Cave and Maoer Mountain in root nitrogen concentration of the first-order root,the same as carbon-nitrogen ratio,both of which were significantly different from those in Changbai Mountain.There was no significant difference between Fairy Cave and Changbai Mountain in carbon concentration of the first-order root,the differences between the mountains were significant.Compared with the morphological characteristics,The variation of fine root chemical composition is smaller.When the environment changes,the fine root will adjust each trait to achieve the best survival strategy.Woody plants that have a large advantage in diameter,length,and surface area will improve their ability to absorb water and nutrients by increasing root length,diameter,and surface area;some woody plants with small roots will improve their absorption efficiency of nutrients and water by increasing specific root length and branch strength of fine roots.This variation of fine root may be a survival strategy that woody plants is adapted to different environments in the long-term evolution.