Characteristics Of Variation In Fine-Root And Leaf Functional Traits Of Different Temperate Tree Species And Responses Of Fine Roots To The Nitrogen-Water Interaction

Plant functional traits can reflect the characteristics on response and adaptation of plants to the growing environment.Researches on plant functional traits contribute to understand the changes in survival strategies of plants under global change.Fine roots and leaves are important under-and above-ground functional organs of trees.The variability of functional traits and responses to increased nitrogen deposition and reduced rainfall to a certain extent determine the function of forest ecosystems under global change.This paper studies the variation in functional traits of fine roots and leaves among various temperate tree species in the Botanical Garden of Shenyang Agricultural University,as well as the response characteristics of fine root anatomy and maycorrhizal fungal infection to nitrogen-water interaction in a broad-leaved Korean pine forests in Changbai Mountains.This research will provide a scientific basis for understanding the impact of global change on the functioning of temperate forest ecosystems.The results of this study mainly indicate:(1)The specific leaf area,leaf nitrogen content,leaf phosphorus content,leafing intensity and fine root nitrogen content and specific root length of different tree species in the Botanical Garden of Shenyang Agricultural University were significantly different,while the leaf water loss rate was not significantly different among different tree species.(2)The specific leaf area of different tree species in the Botanical Garden of Shenyang Agricultural University had a positive correlation with leaf nitrogen content and phosphorus content,and a negative correlation with leafing intensity,specific root length,and fine root nitrogen content.Leaf nitrogen content was significantly positively correlated with leaf phosphorus content and leafing intensity,but significantly negatively correlated with specific root length and nitrogen content of fine roots.Phosphorus content in leaves was positively correlated with leafing intensity,and negatively correlated with nitrogen content and specific root length of fine roots.There was a negative correlation between the leafing intensity and specific root length and nitrogen content of fine roots.The specific root length of fine roots was positively correlated with nitrogen content of fine roots.(3)Nitrogen addition,precipitation reduction and their interaction increased fine-root diameter,vascular bundle diameter and cortex thickness of different tree species in the broad-leaved Korean pine forest in Changbai Mountains.(4)There were different responses of stele/root ratio of fine roots to nitrogen-water interaction among different tree species in the broad-leaved Korean pine forest in Changbai Mountains.In nitrogen addition and precipitation reduction plots,the stele/root ratio of Tilia amurensis decreased,while that of Quercus mongolica increased.Nitrogen-water interaction resulted in a reduction in the stele/root ratio of fine roots for Fraxinus mandshurica and Tilia amurensis,while a decrease in stele/root ratio of fine roots for Corylus mandshurica.(5)Precipitation reduction and nitrogen-water interaction increased the pipe density of fine root of different tree species in the broad-leaved Korean pine forest in Changbai Mountains,while nitrogen addition only increased the pipe density of fine roots for Acer mono.(6)The mycorrhizal fungal infection of fine roots of different tree species in the broad-leaved Korean pine forest in Changbai Mountains decreased in nitrogen addition,precipitation reduction and nitrogen-water interaction plots.