Dissertation > Agricultural Sciences > Gardening > Ornamental Horticulture ( flowers and ornamental trees) > Flower trees in class > Peony

Research on Conservation Biology and Genetic Diversity of Paeonia delayayi complex (Peaoniaceae)

Author LiKui
Tutor WangYan
School Chinese Academy of Forestry
Course Ornamental Plants and Horticulture
Keywords Paeonia delavayi dynamics of population pollination biology floweringcharacters breeding system RAPD conservation biology genetic diversity new species Paeonia weisiensis Y. Wang&K. Li sp. nov
CLC S685.11
Type PhD thesis
Year 2013
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Tree peony (Paeonia suffruticosa) is a popular traditional ornamental plant in China and isalso appreciated internationally because of its large showy flowers. The wild groups ofPaeonia sect.Moutan were endemic species of China, and their systematics and classificationhad not uniform standard until now. Specific and interspecific relationships had been reportedin succession since the new species of P. delavayi and P. lutea were published for the first timeby Franchet in1886. Many viewpoints of taxonomy and description of new species accordingto morphological characters were denied and modified continuously. Lack of field surveys andspecimens collection, its can not combined analysis of morphological characters and molecularbiology or other methods. In order to provide reference for solve the systematic classificationof P. delavayi, the pollen morphology of wild populations were examined using scanningelectron microscope, based on field surveys and statistic analysis between2008and2009years,SSR (random amplified polymorphic DNA) makers were used to study the systematicclassification among the wild populations and other all species of Paeonia sect.Moutan. Thestudied results mostly as follows:1) Paeonia delavayi is an endangered plant which is only distributed in the southwest ofChina. This objective was to study the numeric dynamics of the natural populations of thelargest and the most concentrated population in Shangri–La, Yunnan Province, China. Thedistribution area of P. delavayi were investigated in3years, the numeric dynamics ofpopulation was studied using static life table, survivorship and mortality curves, fecundityschedule and Leslie matrix model. Important findings: P. delavayi underwent strongenvironmental screening at ages between three to six years. The physiological life span wasabout15years, and generation span was eight years. The net reproductive rate (R0=0.9857),intrinsic rate of increase (rm=–0.0017) and finite rate of increase (λ=0.9983) were lowrelatively, it indicated that the population was decreasing, the Leslie matrix model showed that the plant numbers from seedlings and shootings declined about50%during the past30years.The survival rate exhibited as step curve (B1type), its mortality rate of individuals weredifferent at every stage, and the killed power (Kx) was very high at the age of six and12years.At present, the population was maintained mainly by shootings and seedlings. Key threats tothe species were most likely the damage of ecological environment and the humandisturbances.2) This objective was to study the seed rain, soil seed bank, and natural regeneration of thenatural populations of the largest and the most concentrated population of ski in Shangri–La,Liangwangshan in Kunming, Mingyongbingchuan in Deqin, Yunnan Province, China.Thedistribution area of P. delavayi were investigated from2010to2012, The seed rain dispersedfrom September to the end of December. In2011, the seed rain intensity in different samplingplots was in the order of Liangwangshan(65seeds·m-2)>Huanxuechang(36seeds·m-2)>Mingyong(13seeds·m-2), and the quantity of the intact seeds in soil supplied for seedgermination and regeneration was48,13and6seeds·m-2respectively. The seed bankreserves was affected by the seed production amount, animals feeding, and seed viability, etc.,of which animals feedingwas the prime factor for the substantial drop of the seed bankreserves. Due to the low resistance against storage and a large number of rot during storage,the seeds in soil could hardly be effectively stored beyond after year to budding.The soil seedreserves in the next May was less than3stands·m-2, it was concluded that the small seed rainreserves, low seed vigor of soil seed bank was the important factors impacting the naturalregeneration of P. delavayi.3) Breeding system and pollination biology were studied of P. delavayi from Shangri-La,Yunnan Province, southwest of China. Flowerings and flower visitors were observed orcollected continuously in2008–2011. The florescence lasted for6d to9d in a single flowerfrom mid-May to late June. High seed rate from the stigma was observed at1d before to3dafter the petals opened, and the dissemination hysteresis was defined as protogyny. The P/Oratios were6,124to9,713:1, suggesting to increase the seed setting rate. 4) Three species of bees, eight species of beetles, seven species of syrphid flies, fourspecies of ants, and three species of butterflies were observed on the flowers. Through pollenexamination on the bodies of the visitors under stereomicroscope and scanning electronmicroscope, much pollen was found from the plants of similar flowering period innercommunity, and indicated that these visitors were not species-specific pollinators. The baggingexperiments showed that P. delavayi has self-incompatibility and no apomixes. Anemophilyonly had a minor role in the fertilization. A few seeds with poor plumpness can be produced ofgeitonogamy. Seed setting rate of artificial xenogamy was higher than natural pollination.Artificial control the species of visitors showed bees being the most important pollinators.Beetles and ants participated in pollination to some extent and were unstable. Syrphid flies andbutterflies with low pollination efficiency. Reproductive success depended largely oncross-pollination assisted by pollinator activities, especially the bees.5) The cluster analysis based on the results was performed by UPGMA: The operationaltaxonomic units of wild species were divided while genetic similarity coefficient among0.47-0.67. And the P. delavayi from different populations were divided into3groups, thesimilarity coefficient was0.68among the yellows, the red-purples and Weixi population whichclosed to the wild species distances as P. qiui and P.osti(i0.67), P. decomposita and P. potanini(0.65). Associated with the morphological characters, it was unreasonable to call the allpopulations as P.delavayi or P. delavayi complex. The research supported to name the yellowsas P. lutea, and the red-purples as P. delavayi.6) A new species of Chinese tree poeny, Paeonia weisiensis Y. Wang&K. Li sp. nov.(Paeoniaceae) is described from Yunnan, China. It is morphologically most similar to P.delavayi and P. lutea, but differs in lower leaves more than13leaflets, lobes in number reach to45-60. Petals11-14in number, light pink, large red radial speckle basal portion, a great manyerose at the apex, Filaments red or purple, anthers yellow. This is study using scanning electronmicroscope and DNA sequencing to study the micromorphology of pollen grains, and molecular data of Paeonia weisiensis, which can provide valuable characters for speciesidentification in the genus and species.

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