【作者】 蔡秀珍；

【导师】 刘克明；

【作者基本信息】 湖南师范大学 ， 植物学， 2008， 博士

【摘要】 本文对凤仙花属Impatiens L.数十种植物进行了种子表皮微形态学、孢粉学、花器官发生和分子系统学研究,主要获得了以下结果:1.通过扫描电镜对凤仙花属15种植物的种子表皮微形态特征进行了观察。结果表明:该属的种子表皮纹饰可分为光滑型、颗粒型、网状型和隆起型四种类型,后两者又可细分为若干亚型,其中负网状亚型和网状-丘状隆起亚型为本文首次报道。供研究的15种凤仙花属植物种子表皮微形态特征差异显著,它们作为属内种的分类鉴别特征具有重要价值;种子表皮的微形态学特征与其物种的部分表型特征具有相关性,在一定程度上反映了属内类群的分化。2.在扫描电镜下首次比较全面的研究了凤仙花属36种植物的花粉形态特征。结果表明:凤仙花属花粉为单粒花粉,具角萌发孔,3沟或4沟,网状纹饰,大小为18.7-45.1×12.5-25.7μm。凤仙花属花粉萌发孔演化趋势为3沟→4沟,具3沟花粉的峨嵋凤仙花I.omeiana等种类为凤仙花属的原始类群,具4沟花粉的匍匐凤仙花I.reptans等种类为该属的进化类群;凤仙花属种间花粉差异主要表现在大小、形状及网状纹饰中网脊宽度、网眼内衍生物等方面。凤仙花属花粉特征,特别是花粉网状纹饰中网眼内有无颗粒状突起及颗粒状突起的形态特征,在属内常具种水平上的可见变异,因而可作为该属分类的重要证据。3.研究了代表不同形态学类型的四种凤仙花属植物花器官发生特征,揭示了其花器官的早期发生式样及动态过程。凤仙花属植物萼片的早期演化趋势为:5个萼片原基独立发生,均完全发育→5个萼片原基独立发生,2个前外侧萼片发育后期消失→3个萼片原基独立发生,2个前外侧萼片原基与旗瓣原基形成“萼片-花瓣复合原基”;近轴花瓣原基最先发生,4个侧生花瓣原基相继成对发生;5个雄蕊原基和5个心皮原基均为轮状同时发生。从花器官发生过程来看,5个萼片原基独立发生且发育完全的锐齿凤仙花代表该属较原始的类型,仅有3个萼片原基独立发生的杏黄凤仙花则代表该属较进化的类型。4.以水角、Tetramerista sp.和Souroubea loczyi为外类群,对凤仙花属30多种代表植物的ITS区和trnL-F序列进行了测定,分别构建了其分子系统树,并将这两个序列结合构建了联合系统树。结果表明:凤仙花科为单系,水角属为凤仙花属的姐妹群,位于系统树的最基部;蒴果为椭圆形或宽纺锤形的种类在分子系统树中基本聚为一大分支,蒴果为棒状或条形的种类则聚为另外的分支,暗示着果实形态可能是该属分类最为重要的性状。从系统树分支结果来看,唇瓣形状、距的长短等性状亦具有较重要的分类学价值,而花梗基部是否具苞片、侧生萼片数目等性状的分类学价值并不显著。分子系统树中,湖南凤仙花和长角凤仙花获得了极高的靴带支持率,分子证据支持将两者归并;而黄金凤和紫花黄金凤(前者的变种)位于不同的分支上且相距较远,分子证据支持将后者提升为独立的种。5.完善和补充了凤仙花属中果实形状和花部唇瓣的形状等特征是该属最为重要的性状;对长角凤仙花等物种的分类学地位进行了探讨;发现了凤仙花属一新种,即岩生凤仙花Impatiens rupestris K.MLiu et X.Z.Cai。更多还原

【Abstract】 The phylogeny of Impatiens L.is comprehensively investigated based on micromorphological features of seed surface,palynology,floral organogenesis and molecular systematics.The main results are summarized as follows.1.Micromorphological features of seed surface of 15 species in Impatiens L.have been examined under the scanning electron microscope (SEM).According to the characters of the epidermal ornamentation of seed coat and the granules on the cell surface,the micromorphological features of seed surfaces in Impatiens could be divided into four types, namely,laevigate,granulate,reticulate and protrusive.The latter two types could be further divided into subdivisions according to the shape of the epidermal ornamentation of the seed coat.The areolate subtype and the reticulate-colliculate subtype were observed for the fist time.The results showed that the micromorphological features of seed surfaces in Impatiens were different among different species,and therefore it could be used as reliable diagnostic characters to identify species.The micromorphological features of seed surface were closely correlated with the gross morphology characters,so it maybe suggests the phylogenetic relationships in Impatiens. 2.The pollen morphology of 36 species of Impatiens in China has been examined under SEM.In these species,the pollen grains are goniotreme,3-colpate or 4-colpate,actinomorphic or zygomorphic, reticulate exine ornamentation.The size of pollen grains is 18.7-45.1×12.5-25.7μm.The evolutionary trend of the germination apertures of the pollen grains in these species may be from the 3-colpate to 4-colpate germination aperture.The species of 3-colpate germination aperture such as I.omeiana etc may be an original group,while the species of 4-colpate germination aperture such as I.reptans etc may be an evolutive group.The length of polar axis,equarorial axis,width of apertures and spine,and the shape of pollen are different to some extent among these different species.The results showed that the species of Impatiens can be classified on the basis of the pollen morphology, especially the granule characters of exine ornamentation.The exine sculptures are different among different species and therefore can provide some proof for identification of some species in Impatiens.3.The floral organogenesis of four species in Impatiens,which represent different floral morphology,has been observed for the first time under SEM.The development pattern and processes of floral organogenesis of the four species were observed.The evolutionary trend of the sepals in these species may be from five sepal primordia initiate independently and develop completely to five sepal primordia initiate independently and only three develop,then to only three sepal primordia initiate independently and the other two primordia fuse postgenitally with the anterior petal primordia.The four lateral petal primordia grow independently,while the anterior petal primordium always grows first. Five stamen primordia are initiated on an inner whorl,alternating with the corolla.Five carpel primordia arise simultaneously.From the point of floral organogenesis,the species of five sepal primordia initiate independently such as I.arguta represent the original group in Impatiens, while the species of only three sepal primordia initiate independently such as I.armeniaca etc may be represent the evolutive group in the genus.4.The nrDNA ITS and cpDNA trnL-F of more than 30 species, which represent most of the morphological types,were sequenced.Based on these two sequences four phylogenetic trees are constructed using Hydrocera triflora,Tetramerista sp.and Souroubea loczyi as out groups. The results showed that Balsaminaceae is a monophyletic,and Hydrocera triflora placed the root of phylogenetic trees is sister to Impatiens. Species including oval or broad-spindly capsule formed a clade,and club or strip capsule formed another clade.The result implied the fruit shape maybe an important character to indentify species in Impatiens.By analysing the phylogenetic trees,both the shape of labellum and the length of calcar are important characters.However,the flower-subtending bract and the number of lateral sepal are less important.Based on analyses the phylogenetic trees,the following clade,namely,I. hunanensis and I.longicornuta clade have high bootstrap support,so the author suggest that they should be formed a species;however,I.siculifer and I.siculifer var.porphyrea are placed different clades,so the latter come out in a more significant position which is upgraded an independent species.5.The shape of the fruit,lower sepal(including the spur)and structure of the inflorescence are completed as the most important characters of taxonomy in Impatiens.Moreover,the taxonomic positions of some species such as I.longicornuta etc are discussed.A new species of Impatiens,I.rupestris K.M Liu et X.Z.Cai,sp.nova from China (Hunan Province,Jiangyong County)is described.更多还原