The Effect Of Altitude On Fine Root Functional Characteristics For Larix Principis-rupprechtii

During the process of plant growth,it is important to absorb,convey and transfer for fine root functions.It also play a significant role in the process of material circulation and energy flowing for forest ecosystem or even the biosphere?When the environment changing,it should be make an adaptability according to its demand,which is usually good for its growth.In this study,we investigated the response of fine root morphology anatomic structure and the content of total carbon and total nitrogen to the altitudinal gradient in the Pangquangou National Nature Reserve in Shanxi province,northern China.We measured the variations of fine morphology,anatomic structure and the content of total carbon and total nitrogen among different root orders for Larix principis-rupprechtii(distributed in 1800-2700 m above sea level).The study results are showed as follows.(1)For the same root order,with the elevation increasing,morphological parameters showed:the root diameter increased,and the root tissue density(RTD)decreased,while specific root length(SRL)and specific root surface area(SRA)all increased first and then decreased.However,at each altitude gradient,root diameter and RTD showed decreased along with the root order increasing,but SRL and SRA declined.(2)For the same root order,with the elevation increasing,anatomic structure showed that diameter of vascular bundle(VBD)and V/R ratio all decreased first and then increased,but the cortex thickness(RCT)(first three order)increased first and then decreased.However,at each altitude gradient,VBD and V/R increased along with the root order increasing,RCT(first three order)showed more less evidently for third order than for first and second order.(3)For the same root order,with the elevation increasing,the content of carbon and nitrogen showed:the content of carbon increased for first two ordre,then no significant change for the last three order;the content of N was increase,but the change of C/N was opposite.However,at each altitude gradient,the content of C and C/N performed increasing with the order increasing,but the content of N was declined.(4)The morphology,anatomic structure and the content of carbon and nitrogen of fine roots were all significantly influenced by altitudes and root orders.It has significant correlation with altitude for the diameter,RTD,VBD,RCT,N,C/N and the content of carbon at first two order.Among them,the variability of morphological parameters,anatomic structure and C content mostly occurred in lower order roots.