Introduction And Domestication And Cold Resistant Physiology Of Firmiana Danxiaensis

Firmiana danxiaensis is a deciduous tree of the genus Firmiana,which is resistant to drought and barren.It has high ornamental value with purple flowers in summer and golden leaves in autumn.However,it has not been developed and utilized yet.In this study,we introduced it to Changsha by seed propagation and grafting propagation,and the adaptability indexes such as survival rate and phenotypic data were observed and recorded,also the physiological response and cold resistance tests under low temperature stress were carried out.The conclusions were as follows:1.Introduction and propagation experiment of F.danxiaensis.（1）In the seed propagation experiment,the germination rate of the seeds which peeled 1/5 seed coat was highest,was 33%.The germination rate of the seeds whch fully peeled seed coat was 1%.And the germination rate of the seeds without peeling the seed coat was 0.Soaking treatments with different hormones with different concentrations had no significant effect on the germination rate of F.danxiaensis.（2）In the graft propagation experiment,the affinity of scion of F.danxiaensis and rootstock of F.platanifolia is high,the success rate of grafting with top buds is 96.97%,and the success rate of grafting with lateral buds is 86.76%.The comparison of the branch and leaf traits between the introduced and the indigenous showed that the branch and leaf traits of the grafted seedlings were not significantly different from the indigenous.2.The growth situation of Danxia Indus after introduction.（1）After observing the seedlings of F.danxiaensis for two years,the survival rate of seedlings in the first year was 93.67%,and the preservation rate of seedlings in the second year was 87.88%.The analyze of growth in two years showed that in the seedling stage of 1a～2a,height growth>diameter growth,branch length growth>branch diameter growth,and leaf uniform growth.（2）After one year of observation on the grafted seedlings of F.danxiaensis after introduction,the average annual growth of plant height of grafted seedlings was197.47cm,and the average annual growth of trunk was 17.20mm.The phenotypic characters of annual branch length,branch diameter,leaf length and leaf width of grafted seedlings were not significantly different from those of origin.3.The study on cold resistance physiology of F.danxiaensis showed that the cold resistance of F.platanifolia was the highest,followed by the biennial seedlings and the annual grafted seedlings in Changsha,and the lowest cold resistance was F.danxiaensis in origin.The index,semi-lethal temperature(LT₅₀),of F.danxiaensis from different sources has the highest correlation,and the LT₅₀ were as follows:the F.danxiaensis materials from Danxiashan was-0.598℃;the F.danxiaensis materials from Nanxiong was 1.397℃;the seed propagation F.danxiaensis materials in Changsha was-2.025℃;the graft propagation F.danxiaensis materials in Changsha was-1.146℃;the F.platanifolia materials in Changsha was-6.354℃Combined with the planning map of plant cold resistance in China,it is recommended that the introduction range of F.danxiaensis is the Plant distribution area of mid-subtropical and Tropical monsoon.The north boundary is the isotherm with the annual average lowest temperature of-6.7℃,and the south boundary is the isotherm with the annual average lowest temperature of 4.4℃.