Study On Water Relations Parameters Of Larix Gemelinii From Three Latitudes

Using Larix gmelinii as material,we transplanted 9-year-old Larix gmelinii trees to the southern boundary(Forestry Ecosystem Station of Maoershan) of its distribution area from three locations:Songling,Heihe and Dailing.Analysing the seasonal course,diurnal pattern and changes before and after transplanted,with measuring the water relations parameters of Larix gmelinii from three provenances at transplanted and provenance site,and more comparing the drought-resistance of three latitudes with the integrate evalution index DI to get the response to climate warming,shown the different effect of climate warming on water relations parameters characteristics between different latitudes.The results suggested:(1) The seasonal courses of the water relations parameters of Larix gmelinii transplanted from three latitudes followed responses of plant phenology.These seasonal courses ofΨ_sat,Ψ_tlp, ROWC_tlp,RWC_tlp,AWC andε^max fluctuated sharply in early and last growth season,then kept stable during the blooming growth season.The maximum and minimum occurred in April, May and September.(2)Water relations parameters of Larix gmelinii transplanted from three latitudes showed their provenance differences were insignificant in early and last growth season,butΨ_sat,Ψ_tlp, AWC andε^max showed significantly during the blooming growth season.(3) The changes ofΨ_sat,Ψ_tlp,AWC andε^max were obvious between provenance site and transplanted site,but ROWC_tlp,and RWC_tlp were not so.i.e the value of AWC of groundback was higher than transplanted.AWC margins between provenance site and transplanted site from Dailing,Heihe and Songling were 16.1%,12.93%and 9.75%,which indicated the water-keeping capacity in provenance site was stronger than in transplanted site.(4) At predawn and noon,Ψ_sat,Ψ_tlp,AWC,ε^max and first water potential of Larix gmelinii transplanted from three latitudes showed significantly different;the diurnal changing ability from stronger to weaker were:Heihe,Dailing,and Songling.(5)According the integrate evaluation index ID in transplanted site:the drought - resistance order from stronger to weaker were:Songling,Heihe and Dailing;however in provenance site: Heihe,Dailing,Songling.The similarity of DI from three provenances showed that the higher values occurred in April and October;the minimum occurred in May;the bigger margin occurred in June,i.e(Dailing1.514～1.614);the smaller margin in August.(6) The seasonal courses ofΨ_sat,ROWC_tlp,RWC_tlp,AWC of Larix gmelinii transplanted from three latitudes between 2006 and 2007 were similar;in 2007,every water relations parameters were lower than in 2006,which indicated that turgor pressue-keeping capacity,tolerance of lower water potential and elasticity of cell wall was higher,in 2007 than in 2006, but water-keeping capacity was not so.