【作者】 李奎；

【导师】 王雁；

【作者基本信息】 中国林业科学研究院 ， 园林植物与观赏园艺， 2013， 博士

【摘要】 芍药科（Paeoniaceae）为单科属植物,隶属3组,其中牡丹组（Paeonia sect. Moutan）植物为中国特有,野生类群包括矮牡丹（Paeonia spontane）,卵叶牡丹（P. qiui）,紫斑牡丹（P. rockii）,凤丹（杨山牡丹）（P. ostii）,四川牡丹（P. decomposita）,狭叶牡丹（P.potanini）、滇牡丹（P. delavayi）（或被划分为紫牡丹（P.delavayi）和黄牡丹（P. lutea））,大花黄牡丹（P. ludlowii）。广泛栽培的牡丹（P. suffruticosa）是中国十大传统名花之一,也是中国的候选国花,具有极高的观赏价值和文化价值。本研究所采用的滇牡丹为其复合群体的总称（Paeonia delavayi complex）。滇牡丹是中国西南地区特有珍稀种质资源,其生态环境复杂、花色多样,地理与生殖隔离造成居群表型性状差异较大,不断有新群体被发现和描述,根据形态学命名的观点不断被否定和修正。由于野外调查和标本收集不足,滇牡丹的形态学、孢粉学、分子生物学等未形成系统研究；其黄色花基因资源及其保存和利用意义深远,但育种工作滞后。基于此,本研究持续多年对该类群分布区进行了全面的调查统计和性状分析研究,并通过种群生态学的方法,研究了滇牡丹的种群数量动态,种子雨、土壤种子库以及幼苗的天然更新,以期了解种群变化原因、濒危机制以及生态位拓展策略等。通过开花繁育和传粉生物学观察,分析滇牡丹的开花特性、种子形成的繁育系统学基础和访花昆虫的传粉生物学特征等,以期为滇牡丹的引种利用及新品种的选育创造条件。为进一步探求滇牡丹的遗传多样性关系,通过开发利用分子标记技术对调查和取样的野生居群以及其他野生种进行了系统的研究,并结合形态学和孢粉学的结果对滇牡丹居群间进行比较分析。主要研究结果如下：1)运用种群静态生命表、存活曲线、生殖力表和Leslie矩阵模型研究了中国西南特有濒危植物滇牡丹种群数量动态过程。静态生命表和种群存活曲线表明：滇牡丹在株龄3–6a之间经历了较强的环境筛,其单株生理寿命为15a左右,平均周期为8a,种群的净增殖率（R₀=0.9857）、内禀增长率（r_m=–0.0017）和周限增长率（λ=0.9983）表明其为衰退型种群；滇牡丹种群存活表现为台阶型曲线（B1型）,分别在6a和12a阶段种群消亡率（Kx）较高。Leslie矩阵模型的模拟结果表明,在30a内种群数量呈现出下降趋势,大约下降了50％,其种群数量靠自身根系的萌蘖和种子繁殖共同维持。野生滇牡丹种群数量下降与其自身繁殖特性有关,但主要原因是人为采挖和生态环境的破坏。2)连续3年调查了滇牡丹分布不同群落类型最为典型的三个居群,即,以灌草层为主体的昆明梁王山居群、以灌木层为优势种的香格里拉滑雪场居群、以乔木层为优势种郁闭度较高的德钦明永居群,统计分析了不同种群结构中滇牡丹的种子雨、土壤种子库及幼苗的天然更新。结果表明：在滇牡丹自然生境中,种子雨散布时间为9月上旬至10月下旬,2011年不同居群的种子雨强度为昆明梁王山(65粒·m^-2)>中甸滑雪场(36粒·m^-2)>德钦明永冰川(13粒·m^-2),土壤中完好种子粒数分别为48、21、6供萌发更新,滇牡丹种子储量取决于当年结实量、虫食、动物啃食等因素,动物搬运和腐烂是储量较少的主要原因。种子易脱水失活以及自身上胚轴休眠特性等因素导致次年萌发幼苗数最多不足3株·m^-2,萌蘖植株则相对较多。滇牡丹种子自身的休眠特性、种子库种子活力影响其幼苗的建成,进而影响种群的天然更新和生态适应性。3)以种群数量最大、分布最集中的香格里拉居群滇牡丹群体为研究对象,对其繁育系统特征及传粉生物学特性进行了连续的观察和分析,内容包括开花物候及繁育系统特征、花粉活力及柱头可授期、访花昆虫行为、频率及传粉效果等。研究结果表明：滇牡丹种群整体花期为5月中旬至6月中下旬,单花花期6～9d,花朵虫食率高并促进雄蕊提前散粉；繁育系统中不同套袋实验表明滇牡丹不存在自花授粉和无融合生殖现象,具有较弱的风媒传粉能力,同株异花能产生少量种子,但种子量少且饱满度较低,人工异株异花授粉略高于自然杂交结实率,繁育系统研究认为滇牡丹应为以昆虫为主要媒介的异花传粉植物,自然条件下种子的形成主要依赖于昆虫传粉活动；正常发育的滇牡丹花瓣打开1～2d后自内向外开始散粉,可持续5～6d,花粉量大且活力在常温下持续时间较长,柱头在花瓣打开前1d至打开后3d授粉成功率均较高,散粉滞后可认为是雄蕊后熟；花粉/胚珠比（P/O）值为6124～9713:1,花粉量大,为较高授粉成功率提供了可能性。4)在传粉生物学方面通过对访花昆虫的观察和收集,在滇牡丹花朵中共观察到3种蜂类、9种甲虫类、7种食蚜蝇类、4种蚁类和3种蝶类出现。通过人工控制访花昆虫种类实验和扫描电镜（SEM）观察,结果表明：蜂类是滇牡丹最主要的传粉者,尤其是中华蜜蜂（Apis （Sigmatapis） cerana cerana）和无斑宽痣蜂（Macropis （Sinomacropis）immaculata）；甲虫类和蚁类在一定程度上参与传粉,但很不稳定；食蚜蝇类和蝶类是极不可靠的传粉者,其传粉成功率极低；滇牡丹花朵可散发气味吸引昆虫,并为访花者提供大量的花粉和蜜液,晴天昆虫访花高峰为11:00-15:00,部分蚁类全天停留在花朵之中,阴雨天大多昆虫停止花间活动；滇牡丹同花期植物对昆虫传粉有一定影响,扫描电镜观察发现多数蜂类和甲虫类体表附有其他植物花粉,其传粉不具专一性。5)对云南等地分布的滇牡丹16个居群和其他野生种从形态学和分子标记方法展开遗传多样性的研究,结果利用UPGMA构建的树状图表明每一个野生种都能各自聚为一支,种间的遗传相似性系数为0.47-0.67;滇牡丹居群间在相似系数为0.68时聚为三支,黄色花系居群与红紫色花系居群各占一支,其遗传相似性系数与P. qiui和P.ostii（0.67）、P. decomposita和P. potanini（0.65）相近。结合花色及花器官特征,叶型、叶色及小叶特征,株高及年生长量等形态学性状的差异,研究认为“P. delavayi（滇牡丹）”作为该类群所有分布区域的种名或作为“P. delavayi complex（滇牡丹复合群）”处理不尽合理,在一定程度上支持将黄色花系居群为P. lutea（黄牡丹）和红紫色花系为P. delavayi（紫牡丹）的观点。6)多年的野外调查,发现的维西居群从未被描述过,不同于前人所发表的各个种、变种、变异类型等,通过形态学和孢粉学比较分析,结合分子标记的研究结果,认为维西群体应提升为一个独立种的分类单元,并拟命名发布野生牡丹新种“维西牡丹Paeoniaweisiensis Y. Wang&K. Li sp. nov.（Paeoniaceae）”,采集描述模式标本,并与相似种滇牡丹进行了比较和证明。更多还原

【Abstract】 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.更多还原