Functional Traits Of Leaves And Fine Roots Of Three Temperate Lianas Species

Lianas could cause mechanical damage to the host trees by climbing or twining the host trees,consequently reducing the wood economic value.The colonization and competition ability of lianas are closely related to functional traits of their leaves and fine roots.Recently,the abundance of lianas has increased in temperate forests,but little is known about their functional traits of leaf and fine roots.Herein,we sampled three typical temperate liana species in Maner mountain,Shangzhi city,Heilongjiang province,including two stem twiners(i.e.,Actinidia kolomikta Maxim and Schisandra chinensis(Turcz.)Baill)and one tendril climber(i.e.,Vitis amurensis Rupr),measuring their anatomical,morphological and chemical traits of leaves at different canopy heights.We also examined the anatomical,morphological and chemical traits of first five orders roots.The main objectives were to reveal the distribution and growth status of three liana species in different forest types;to explore the leaves functional traits differences in species and in canopy heights;to clarify the influences of species and root orders on fine root functional traits.Our results showed that:(1)The distribution of three lianas showed interspecific differences,which mainly growing in the secondary forest with sparse upper canopy and the plantation with low density.The main host trees and canopy positions of three liana species were also different.The leaves of A.kolomikta were mainly in the upper part of the forest canopy,while the leaves of other two species were throughout all the canopies.(2)There were significant differences in leaf anatomical,morphological and chemical traits among three species.The specific leaf area,thickness of palisade and spongy tissue were largest for A.kolomikta.V.amurensis had the lowest thickness of upper epidermal,lower epidermal,palisade and spongy tissue,leaf and C/N ratio,and the largest leaf tissue density,specific leaf area and total nitrogen content.Stomatal density of S.chinensis was the lowest when somatal length was the largest.(3)Both leaves of S.chinensis and V.amurensis showed the similar changes with increasing of canopy heights(A.kolomikta was excluded owing to the leaf deficiency in lower canopy).The effect of canopy heights on leaf stomatal density and stomatal length was not significant.The values of anatomy were lowest for the lower leaves for both S.chinensis and V.amurensis.The anatomical traits of S.chinensis decreased with the increase of canopy heights.The thickness of sponge tissue and leaf,and leaf tissue density decreased with the increase of canopy heights,while the specific leaf area increased.(4)The functional traits of fine roots showed significantly specific variations.Anatomically,both diameters of stele and widest conduit of the 5th order roots were largest in V amurensis and smallest in A.kolomikta.And stele diameter of the 5th order root varied significantly among species.For 1st order root,V.amurensis had lowest ratio of cortical thickness to stele diameter,root diameter and tissue density,but largest root branching ratio and specific root length.A.kolomikta had the largest total nitrogen content,while S.chinensis had the lowest.The total carbon content of the 2nd to the 5th order fine roots varied significantly among species.The mycorrhizal colonization rate of the 1st order roots was lowest in V.amurensis(1 5.94%),but highest in S.chinensis(95.71%).(5)Among the root orders,there were significant increase in the stele diameter,the widest conduit diameter,root diameter,root tissue density and root C/N ratio with the increase of root orders,but significant decrease in the ratio of cortical thickness to stele diameter,specific root length and total nitrogen content.The double cell wall thickness of conduits increased with the increase of root orders in S.chinensis and V.amurensis,but no significant variations in A.kolomikta.