A Study On Germplasm Resources Of Polygonati Rhizoma

According to research contents and methods of plant germplasm resources combined research methods of pharmacognosy,bencaology,investigation,collection,identification,evaluation and application of polygonati rhizoma germplasms were systematically studied.Results would provide theoretical basis and technical supports for germplasms identification,higher quality germplasm screening,breeding and germplasm resources protection system construction and related research,which can promote rational and effective utilization and sustainable development of polygonati rhizoma and safeguard healthy development of the modern polygonati rhizoma industry.The main results are listed as follows.1.Polygonati rhizoma,a kind of medicinal and edible products with a long planting and medicinal history in China,has important dual functions of biology and sociology,including medicinal,edible,economic,cultural and social value.Polygonati rhizoma was divided into "Zhenjing" and "Pianjing",and Zhenjing has a better curative effect than Pianjing in traditional Chinese pharmacy system.Whereas,it is identified as Polygonatum sibiricum Red.in flora of China in modern botany and taxonomic system.In addition,it is the dry rhizomes of Polygonatum sibiricum Red.,Polygonatum cyrtonema Hua and Polygonatum kingianum Coll.et Hemsl in Chinese Materia Medica and Pharmacopoeia of China.2.A wide range of Polygonatum species are widly distributed in the world with a strong adaptability.Almost 326 kinds of Polygonatum plants have reported,87 of them have been generally recognized.The main distribution area is East Asia,the hot area is China,and the diversity center is southwest of China.A total number of 40 kinds of Polygonatum species are widely distributed in China.In this study,samples of polygonati rhizoma germplasms were collected from 50 different growing regions and planted in polygonati rhizoma GAP base(Buchang Pharma,Lueyang,Shaanxi,China).3.Molecular markers and morphological markers can be used for polygonati rhizoma identification.Germplasm resources were identified as 7 species,respectively,ie.,polygonatum cyrtonema,Polygonatum sibiricum,Polygonatum kingianum,polygonatum cirrhifolium,Polygonatum alternicirrhosum,Polygonatum punctatum and Disporopsis longifolia.Therefore,it is of great significance to construct molecular marker information database for polygonati rhizoma identification combined molecular markers with morphological markers.4.A total of 60 indicators were selected as evaluation index of germplasm resources,and membership function method was used to evaluate germplasms.The top of 20%(hierarchical probability distribution)of germplasms were screened as excellent germplasm for each index.Results showed that evaluation was not the same with different evaluation indexes.Therefore,single or some evaluation index can not be scientific and reasonable for characterizing germplasm characteristics.5.Various of comprehensive evaluation methods and multi-evaluation indexes were used to evaluate germplasms,and the top of 20% of germplasms were screened as excellent germplasm for different evaluation methods.The results showed that germplasms collected from Hezhou,Lveyang,Songxian,Ningqiang and Longnan were excellent.6.A total number of 60 identification and evaluation index were screened out for establishing technical specifications of polygonati rhizoma germplasms identification and evaluation with collected experimental data and image information.Therefore,it has an important application value for standardizedi describing and definiting reasonable identification and evaluation index for polygonati rhizoma germplasms.7.Germplasm screening results varied with different needs(medicinal materials and reproductive materials).Based on economic traits,germplasms collected from 13 regions were selected as excellent materials,such as Yizhou,Qingyang,Lveyang and others.While,combined economic traits with complete growth period,germplasms collected form Lingbao,Songxian,Ningqiang and Lveyang were selected as excellent materials.8.ISSR and SCoT molecular markers were used for genetic diversity analysis and evaluation of germplasms,and core germplasms were screened and identified for establishing primary core germplasm repository.Germplasms collected from Guizhou,Yunnan,Guangxi and Zhejiang has abundant genetic diversity,whereas,genetic diversity of germplasms collected from Chongqing,Sichuan,Jiangxi and Shaanxi is low.Germplams of 13 regions,including Chizhou,Qingyang andYimen,can be used to build a primary core collection reposotory.9.Two Polygonatum sibiricum hexokinase gene fragment with 656 bp long were obtained by homologous clone strategy.They are as the highest similarity with Asparagus officinalis hexokinase-2-like,which indicated that genetic relationship of them is closer.Two gene fragments have conserved domain of hexokinase-1,which belongs to the HK2 family.Hexokinase has a higher expression in leaves and stems,while the expression in dormant buds,new rhizomes and initial rhizomes is lower.In the new rhizome,expression of hexokinase increased and glucose metabolism is active.Expression of hexokinase in rhizome decreased,which made glucose metabolism decrease and sugar accumulation increase under water stress.10.Gene fragment of ascorbate peroxidase,glutathione peroxidase,glutathione reductase and monodehydroascorbate reductase,dehydroascorbate reductase,catalase,superoxide dismutase and peroxidase in anti-oxidase system were obtained by homologous clone strategy.The metabolic activity of ascorbic peroxidase is in new rhizomes;metabolic activity of glutathione peroxidase,catalase and peroxidase were in leaves;glutathione reductase and monodehydroascorbate reductase were in initial rhizome;metabolic activity of dehydroascorbate reductase were in the remaining tissue apart from dormant buds.Glutathione peroxidase,glutathione reductase and monodehydroascorbate reductase participated in metabolic activities in neonatal rhizomes,and the remaining antioxidant enzymes involved in metabolic activity mainly in initial rhizomes for the regulation of plant senescence.Under different water treatments,the difference in the expression all kinds of anti-oxidase in antioxidase enzyme system was significant,and the varied trend of expression was inconsistent.11.Study on germplasm resources of polygonati rhizoma should be a multi-discipline,multi-system,multi-level,all-round,three-dimensional,open and comprehensive study based on the material base,energy base,value library and information database combined study on natural science and social science.Constructing a scientific,reasonable and accurate research system of polygonati rhizoma germplasms would be an important content of scientific research in future.