Studies On Germplasm Resources Of The Genus Of Primula In North-West Yunnan Province And Core Germplasm Of Primula Denticulata Ssp. Sinodenticulata

Primula is a famous alpine flower distributing throughout the moister and cooler regions of the northern hemisphere. By far the largest concentration of species is found in the great chain of Himalaya and western China, especially Hengduan Mountains in southwest China is the modern distribution and diversification centre of the genus Primula, and of which Yunnan Province has more than 120 species. Most species are beautiful and many species have proved to be great garden or ornamental flowers. The flower trade of Primula creates hundreds of millions dollars annually in American. While the study in China is far behind, and the Flora Reipublicae Popularis Sinicae on Primulaceae was completed until the early 1990s. In the past twenty years, the germplasm resources of Primula were destructed due to environmental factors and human factors (infrastructure construction, tourism development and so on). And as the genus Primula is mainly located in higher altitude mountain regions, the characteristic of low heat resistence restricts its introduction and horticultural development process in China. Based on related documents and specimens, a field surney was carried out in northwest Yunnan Province. One representative Primula species, P. denticulata ssp. sinodenticulata was studied for the analysis of genetic diversity and establishment of conservation strategy.The main conclusions are as follows:1.During 3 years field survey in northwest Yunnan Province, 55 Primula species (including sub-species and varieties) belonging to 18 groups were located, which account for 50% of the species in Yunnan Province. The characteristics of Primula germplasm resources in this region were as follows: (1) species diversity was abundant and population density was variant, (2) distributed widely, habitats were complicated and various, (3) vertical distribution pattern appeared definite regularity. 2. According to comprehensive quantitative evaluation on ornemantal traits and ecological factors, 15 Primula species including P. sinolisteri, P. bathangensis, P. polyneara, P. forrestii, P. poissonii, P. wilsonii, P. chungensis, P. sikkimensis, P. faberi, P.sinopurprea, P. monticola, P. denticulate ssp.sinodenticulata, P. vialii, P. pinnatifida, P. deflexa have higher introduction value.3. 10 natural populatons of Primula denticulata ssp.sinodenticulata were located in Yunnan Province and 6 populatons in the region of Kunming, Song Ming, Yi Mun, Yuxi, Lijiang and Lushui were dismissed. And compared with to the records, population number and distribution area both had a certain degree of reduction, and its natural distribution had been fragmented. 300 copies pf these plants were chosed for initial core collection. The sampling strategy of core collection was established based on genetic diversity of morphological and AFLP markers, which includes (1) conserving 5 populations, (2) genotype conservation way by sampling 27～31 genotypes for each population.4.Ca2 + participated in the response of Primula denticulata ssp.sinodenticulata to heat stress as an important mineral nutrients. Results of related physiological indicators and heat harm index showed: Ca2 + treatment (20 mmol / L) could effectively inhibit the MDA's rapid accumulation in leaves of this plant and improve increase of proline. Besides the treatment could also improve and maintain the activity of Ca²⁺-ATPase enzyme, and decrease the high harm index in 40 %. Chemical treatment of Ca2 + could improve the resistance of Primula denticulata ssp. sinodenticulata to heat stress in some extent.5. The technology of mRNA differential display was employed to isolated heat stress responsive genes in the leaves of Primula denticulata ssp.sinodenticulata. More than 1000 cDNA segments were amplified and 111were differeantial display. There were 5 cDNA segments only expressed in the state of heat stress. In the isolated segments, HSR4 shared 62% homology with HSP68 protein from Solanum tuberosun, 55% homology with mtHSC70-2 protein from Arabidopsis thaliana. HSR5 shared 70% homology with HSP90 protein from Nicotiana tabacum. Their expressions were possible involvement in the heat stress response, but their structure and function need to be further studied.