Research On The Endangered Causes And In Vitro Cultivation Technology Of The Extremely Narrowly Endemic Plant Chrysopsis Radiat

The endangered system and conservation strategy of rare plants is one of the key tasks of plant diversity conservation.China is one of the main distribution areas of bryophytes,distributed in the south and southwest.Southwest China is the rich distribution and endemic center of bryophytes in China,and the climate with abundant rainfall and unique geological landforms have formed a unique habitat suitable for the survival of endemic species,giving birth to many endemic species with great scientific research value.Oreocharis esquirolii,endemic to Guizhou,is a perennial herb with purple or blue corolla that blooms in August,was incorporated into the genus Oreocharis in 2011,and was listed as a national first-class key protected wild plant in2021,growing on nutrient-poor exposed rock walls,scarce in numbers,and at risk of population extinction as the environment deteriorates and the physiological characteristics of its species.At present,the research on O.esquirolii is limited to the investigation of plant communities,and has not been further studied,as an endangered and endemic species in Guizhou,we can conduct preliminary discussions from the aspects of endangered system,ex situ conservation,and ex vivo conservation.Therefore,this paper takes O.esquirolii,a plant endemic to China in the middle extreme narrow area of the genus Generalized Oreocharis as the research object,and intends to find the most critical limiting factors for species endangerment through a series of index analysis.It provides a basic basis for biodiversity conservation in Guizhou.（1）According to the basic overview of the habitat of O.esquirolii,it can be seen that most plants grow on the rock wall,the soil is very little,the slope is more than 75°,the whole habitat is located on the downslope of the shady side of the mountain,the distribution area is extremely narrow and discontinuous,and it is scattered on the cross-sectional rock near the river bank in a state of aggregation.The community structure data showed that the community of II in the Lengshui River area was composed of 17families,18 genera,19 species,the community of II was composed of 19 families,26genera,28 species,and the community of III was composed of 15 genera in 11 families,15 species.（2）The soil p H of three plant community in Lengshuihe area in the study area is slightly acidic,ranging from 3.68 to 4.16.The average p H and TK of rhizosphere soil（r）are significantly lower than those of non rhizosphere soil（b）;The average values of TN,AN,and TP in rhizosphere soil（r）were significantly higher than those in non rhizosphere soil（b）;The soil TN content of II was significantly higher than that of I and III;The AP of rhizosphere soil（r）in I and III was significantly lower than that of non rhizosphere soil（b）,and there was no difference in II;The AK of rhizosphere soil（r）in I was significantly higher than that in non rhizosphere soil（b）,while the AK of rhizosphere soil（r）in II and III was significantly lower than that in non rhizosphere soil（b）.Environmental factors p H and TN were more correlated with species at the taxonomic level of bacteria,TP,AN and AK were less correlated with species at the taxonomic level of bacteria,and environmental factors p H,water content and TP were negatively correlated with TN,TK,AK and AP,and positively correlated with AN.Environmental factors TN and TP were more correlated with species at the taxonomic level of bacteria,TK and AK were less correlated with species at the taxonomic level of bacteria,and environmental factors p H,water content,TK and AK were negatively correlated with TN,TP,AN and AP.（3）The ratio of the number of sequences at the boundary,phylum and class levels to the total annotated data in the three plant communities of the Lengshui River area I.,II.and III.was small,and the ratio of the number of sequences at the family,genus and species levels to the total annotated data was significantly smaller than that of points I.and III.After analysis and statistics,bacteria（96.94%）accounted for the largest proportion of species.The dominant bacterial species in the rhizosphere（r）and non-rhizosphere（b）soil samples were Actinobacteria and Proteobacteria,respectively,and the dominant bacteria were Bradyrhizobium and Paraburkholderia.At the phylum classification level,all samples were similar in the phylum Actinobacteria,Proteobacteria,and Acidobacteria.The LDA abundances of Metabolism of other amino acids and amino acid metabolism in rhizosphere soil samples were significantly higher,and energy metabolism,cofactors and vitamins in non-rhizosphere（r）soil samples were significantly richer.The abundance of LDA values in lipid metabolism is significantly higher.The gene set of K01915 is mainly glutamine synthetase,and the proportion of rhizosphere（r）soil is greater than that of non-rhizosphere（b）soil.The gene set of K01673 is mainly carbonic anhydrase,and the difference between the two is small;The K00265 gene set is mainly glutamate synthase（NADPH）large chain,and the proportion of non-rhizosphere（b）soil is greater than that of rhizosphere（r）soil.（4）Taking the endangered plant O.esquirolii as the research object,the photosynthetic physiological characteristics of leaves were measured in the simulated habitat of the conservation area,and the leaf anatomy was observed to explore the difference between the photosynthetic ability of O.esquirolii and the physiological structure of leaves.The results showed that the F_o of Borage was 320.5(μmol·m^-2·s^-1),Fv/Fm was 0.71,F_v/F_o was 2.41,Y（II）was 0.66,ETR was 0.94(μmol·m^-2·s^-1),and the daily average P_n value of O.esquirolii was 0.31(μmol·m^-2·s^-1),and the relative fluctuation range was small.The mean P_max value of the leaf was 2.24(μmol·m^-2·s^-1);The mean R_d and LCP values were 1.14(μmol·m^-2·s^-1)and 51.85(μmol·m^-2·s^-1),respectively.The mean LSP of the light response curve was 294.47(μmol·m^-2·s^-1).The photosynthetic CO₂ response curves were obtained by fitting with a V_cmax of 7.63(μmol·m^-2·s^-1)and a J_max of 26.04(μmol·m^-2·s^-1).The average LT of this species is304.48μm.UE is 37.80μm.LE is 38.09μm.PT and ST are 40.79μm and 30.07μm.（5）Take the leaves of O.esquiolii as explants,the optimal disinfection and sterilization method was 75%alcohol for 20 s and 0.1%ascending mercury soaked for5 min.The optimal combination for callus induction and adventitious bud induction was C9(1/2MS+4.0 mg·L^-16-BA),F1(1/2MS+4.0 mg·L^-16-BA+0.1 mg·L^-1NAA).The optimal combination for strong seedling culture was T1(1/2MS+4.0 mg·L^-16-BA+0.2mg·L^-1NAA+0.1 mg·L^-1IBA).The optimal combination for rooting culture had two groups,T6(1/2White+4.0 mg·L^-1 6-BA+0.2 mg·L^-1NAA+0.1 mg·L^-1IBA)and T8(1/2White+4.0 mg·L^-16-BA+0.2 mg·L^-1NAA+0.5 mg·L^-1 IBA).The equal proportion of grass charcoal:vermiculite:perlite combined matrix was optimal,and the survival rate of transplanting was as high as 93.3%.This study provides scientific basis for the ex situ conservation,germplasm conservation and further conservation of the endangered plant O.esquiolii.