Study On The Foraging Behavior Of Clonal Roots And Its Influencing Factors Of Populus Euphratica

In the situation of global change,water shortages and changes in hydrological processes profoundly affect plant adaptation strategies.In extremely aird oasis,clone growth is the main reproduction way of Populus euphratica,which plays an important role to the recruitment and persistence of the population in arid-climate region because of water shortages.The clonal roots of P.euphratica is the carrier of clonal growth.This paper attempts to clarify the difference between the proximal and distal roots foraging behavior of clonal roots of P.euphratica in heterogeneous natural forest habitat,provide theoretical and scientific basis for the protection of P.euphratica to estimate the clonal roots distribution characteristics and the key influencing factors of foraging behavior traits including main roots depth(MRD),roots diameter(RD),main roots length(MRL),fine roots biomass(FRB),roots sucker density(RSD),soil factors and biotic factor..In this study,clonal roots branches were manually excavated and investigated by typical sampling method and grid-sampling method survey in the Ejin Oasis,Inner Mongolia of northern China.(1)The characteristics of the proximal roots and the distal roots are significantly different.The MRL and RD of the proximal roots are larger than that of the distal roots,which is beneficial to the individual plant to find a better environment and improve the C-storage ability.The FRB of the distal roots and the RSD are large,so as to achieve nutrient acquisition and generation of ramets(the MRD of the proximal roots,the RD,and the MRL are significantly greater than the distal roots,the FRB,and the RSD are significantly less than the distal roots).(2)In addition to environmental factors,the expansion behavior of P.euphratica clonal roots is also affected by biotic factors(the MRL is positively correlated with soil total phosphorus and soil compaction,the MRD of the distal roots is negatively correlated with the biomass of nearby roots,total carbon content in the soil had a major positive influence on the RD,and the FRB of the distal roots is mainly affected by the positive effects of soil water content,total nitrogen content of the soil,biomass of nearby roots and soil compaction.Soil water content and biomass of nearby roots have a positive effect on the RSD of proximal roots).(3)The horizontal distribution strategy of clonal roots tends to distribute more clonal roots in the 0-20 cm soil layer within a range of 12-15 m from the sampling point,thus changing the location of the genet to achieves horizontal movement within the community.Tamarix spp.has an inhibitory effect on the propagation of nearby clonal roots in the 0-40 cm soil layers,and has a weaker influence on the clonal roots growing at a distance of 9 m(the clonal roots distributed in the overall range of 0-40 cm will be negative influenced by shrubs in the range of 3-6 m.Shrubs which distributed in the range of 9 m can promote the biomass of the clonal roots of P.euphratica in the 0-20 cm soil layer).The clonal roots was likely to avoid competition with nearby plant roots for resources when grown together,and improve its abilities to uptake nutrients,occupy space and produce new rootsing units to improve its competitiveness in the community in the process of maintaining population recruitment.