来江藤属系统发育及花性状演化

	来江藤属系统发育及花性状演化; Phylogeny and floral trait evolution of Brandisia
	陈哲
导师	孙航
摘要	Pollination is essential for reproduction of most angiosperms, and floral traits evolve to adapt pollinators in this plant-animal interaction process. Species in Brandisia show floral traits diversity, such as flower colour and morphology. We conjecture that this may be adaptation to pollinator shifts. In order to test our hypothesis and explore floral trait evolution pattern in this genus, we integrate pollination and phylogenetic research to make this a relatively comprehensive research on Brandisia. First, the phylogeny of Brandisia was reconstructed using molecular data, based on comprehensive sampling. This phylogeny could then be used in the analyses of floral trait evolution. Pollination study was carried out in the field and the phylogeny reconstructed was combined in analyzing floral trait evolution. Many species in Brandisia have floral traits of typical ornithophily (pollinated by birds), such as red flowers. Birds and bees differ in colour vision and show different sensitivities to red signals. Although similar to human, red flowers pollinated by bees and birds probably differ in reflectance and function. To explore the colour characteristics of red flowers pollinated by birds in Brandisia, bee-pollinated flower, Onosma confertum (Boraginaceae), was used for comparative analyses. The function of secondary peaks (occurs at the wavelengths outside of the main reflectance) in red flower spectra was evaluated. The main results are showed below: 1. Phylogeny of Brandisia Plastid genomes were assembled and four nuclear gene sequences were filtered based on genome skimming data of Brandisia. The four nuclear genes are: ribosomal RNA (3S), phytochrome A (PHYA) and phytochrome B (PHYB, which has two copies in Brandisia). 1) Unlike the most species in Orobanchaceae, Brandisia plastomes showed integrity in structure, and no rearrangement was found except for slight expansions of Inverted Repeats. No pseudogene was found in Protein coding genes. 2) The phylogenetic trees derived from both complete plastome data and combined nuclear sequence data support the monophyly of Brandisia. However, the relationships between Brandisia species showed discordance. This plastid-nuclear discordance may be caused mainly by hybridization between species. The hybridization between B. hancei and B. discolor was observed and confirmed. Hybridization is likely to be the reason for separation of different B. discolor lineages in phylogenetic tree based on plastome data. The phylogenetic tree based on plastome data is affected by plastid capture event. Therefore, the species tree derived from nuclear data maybe more reliable. The species tree shows three main clades in Brandisia. B. rosea var. flava forms the early-diverged lineage. The second clade contains B. racemose and B. cauliflora. The rest of all (B. hancei, B. glabrescens, B. kwangsiensis, B. swinglei and B. discolor) form the third clade. 3) B. chevalieri and B. scandens in Vietnam only show slight differenc
	2020-11
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/74116
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	陈哲. 来江藤属系统发育及花性状演化, Phylogeny and floral trait evolution of Brandisia[D],2020.

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