Investigation,Preservation And Evaluation Of Hydrangea Germplsm Resources In Qinling Mountains

Hydrangea plants are a perennial woody plant which belongs to the Saxifragaceae.They are ultra-rich plants of aluminum with fully floral and rich colors.They are resistant to heavy metal cadmium and lead.Because of their high ornamental,ecological,medicinal and economic value,Hydrangea plants have broad application prospects in various fields.The resources of the genus Hydrangea in China account for more than 60%of the world’s Hydrangea,but at present many wild resources have not been fully protected and utilized.In view of this problem,the author investigated and collected the germplasm resources of wild Hydrangea in Qinling region.The distribution,phenotypic characteristics and reproduction of Hydrangea were studied.The main results were as follows:(1)In the natural area of Qinling Mountains,seven species(Hydrangea longipes,Hydrangea rosthornii,Hydrangea villosa,Hydrangea strigosa,Hydrangea bretschneideri,Hydrangea xanthoneura,Hydrangea heteromalla)of two group(Sect.Heteromallae,Sect.Hydrangea)had been found here.(2)Horizontally,Hydrangea rosthornii and Hydrangea bretschneideri were observed in more areas and wider-ranging distribution than others.Hydrangea longipes and Hydrangea strigosa were distributed in two survey areas,while Hydrangea villosa,Hydrangea xanthoneura and only appeared in one survey area,with the limited distribution and weak adaptability.In vertically,wild Hydrangea were distributed at the elevation of 500 to 3400m.Hydrangea rosthornii has a huge variation in altitude,reaching 2100m,followed by the Hydrangea bretschneideri,with an altitude range of 1916m.Hydrangea strigosa and Hydrangea xanthoneura had smaller altitude span of 1300m.(3)In terms of resource characteristics,wild Hydrangea plants were mainly distributed in sparse forests of hillside,roadsides of hillsides and streamside thickets,with mostly sporadic and interruptive distribution.In the wild Hydrangea communities,only one or two species were distributed in each place,and there were no newborn small seedlings in the lower layer.Hydrangea bretschneideri,Hydrangea xanthoneura and Hydrangea heteromall of Sect.Heteromallae were mainly large shrubs and small trees.They grew in unshaded places,and had strong light and drought resistance.Hydrangea longipes,Hydrangea rosthornii,Hydrangea villosa and strigosa of Sect.Hydrangea were small shrubs,mostly distributed in shade and humid places.They had good shade resistance.(4)Phenotypic variation analysis and systematic observation were carried out for qualitative traits and quantitative traits of seven species in Qinling Mountain area.There were some differences in the average CV among the different quantitative characters of the seven species,among which the average CV of petiole length was the largest and the stability was the worst.CV of the traits of Hydrangea strigosa was the largest,and CV of Hydrangea longipes was the smallest.Stem internode’s length,pregnant flower’s color,petiole’s color,unfertile flower’s color and leaf shape were the characteristic trait for Hydrangea based on PCA.The results of Q cluster analysis were consistent with the traditional morphological classification results.Hydrangea bretschneideri,Hydrangea xanthoneura and Hydrangea heteromall of Sect.Heteromallae clustered together.Hydrangea longipes,Hydrangea rosthornii,Hydrangea villosa and Hydrangea strigosa of Sect.Hydrangea were grouped together.(5)The results of seed germination test showed that dark conditions were not conducive to the germination of Hydrangea seeds.After soaking Hydrangea seeds in 1000mg·L-1 GA3 for 48h,advance germinate in an artificial climate box at 20001x/24h/d at 20℃,which can significantly advance the initial germination time of the seeds,improve their germination rate,germination potential and germination index.(6)The best proliferation medium for Hydrangea rosthornii was MS+1.0mg·L-16-BA+0.2 mg·L-1 IBA,on which the proliferation coefficient was up to 10.67.The suitable rooting medium for Hydrangea rosthornii was 1/2MS+0.1mg·L-1IBA+0.5 mg·L-1NAA,on which the rooting rate reached 100%.The best proliferation medium of Hydrangea bretschneideri was WPM+0.1mg·L-16-BA+0.1mg·L-1IBA,on which the proliferation coefficient was as high as 9.00.The suitable rooting medium for Hydrangea bretschneideri was 1/2MS+0.1mg·L-1IBA+0.5 mg·L-1NAA,on which the rooting rate reached 100%.The best proliferation medium for Hydrangea strigosa was MS+0.8 mg·L-1 6-BA+0.05 mg·L-1 NAA,on which the proliferation coefficient was up to 9.00.The suitable rooting medium for Hydrangea strigosa were 1/2MS+0.1 mg·L-1 IBA+0.1 mg·L-1 NAA and 1/2MS without hormones,on which the rooting rate reached 100%.The best proliferation medium of Hydrangea longipes was MS+0.8 mg·L-1 6-BA+0.2 mg·L-1 IBA,on which the proliferation coefficient was as high as 9.67.The suitable rooting medium for Hydrangea longipes were 1/2MS+0.2 mg·L-1 IBA+0.5 mg·L-1NAA and 1/2MS without hormones,on which the rooting rate reached 100%..