特殊油料树种琴叶风吹楠分类学位置及遗传多样性研究

Horsfieldia pandurifolia, one endemic endangered species in Yunnan province of China, is a kind of rare tree because its seeds are rich in peculiar oil and the oil consists of plentiful 14-C acid（more than 90%）. Horsfieldia pandurifolia is wild only in tropical rain forest land and the number of individuals are very few. Its taxonomical position have been debated and the research achievement of population genetic diversity have been not found.In previous reseach subject (30872046),the investigation of resource distribution was carried out and the patterns of variation of phenotype and oil composition were analyzed.The results showed that there were obvious differences between research achievements and literatures, and some taxonomical new evidences of Horsfieldia pandurifolia have been found. In this research subject, the work for Horsfieldia pandurifolia in the aspects of taxonomical position, genetic diversity, the number of haplotye and the pattern of haplotype distribution will be carried out by morphology,chemotaxonomy, AFLP and SNPs(cpDNA, mtDNA and nrDNA). The results will be gained in the following:. 1)taxonomical position of Horsfieldia pandurifolia;. 2)population genetic variation and genetic structure;. 3)the number of haplotype and space distribution of haplotype;. In addition,combining vicissitudes of flora, geography and weather, the cause of formation of genetic structure and the species migration for Horsfieldia pandurifolia will be explored base on the data of gene flow and genetic differentiation among local populations.. The results are useful for academic research, cultivar breeding and protecting Horsfieldia pandurifolia germplasm at conservation in situ and conservation ex situ.

琴叶风吹楠（Horsfieldia pandurifolia）是典型热带分布树种，种子含油率62%，其中十四碳酸占90%，是特种油料资源植物，已处于濒危状态，分类学位置争论不休，遗传多样性没有研究。在前一项目（30872046）中，课题组已掌握资源分布现状、形态变异、油脂成分变异式样和繁殖技术，研究结果与文献记录差异甚大，在分类学证据方面有了新的发现。本项目将结合形态学、化学分类学和分子系统学研究其分类学位置；在居群水平上利用分子标记AFLP和SNPs（cpDNA、mtDNA、nrDNA）的方法开展研究，结合表型变异和生物学习性揭示琴叶风吹楠群体遗传多样性，揭示单倍型（haplotype）数量及其在居群间的分布；基于居群间的遗传分化、基因流等数据，结合植物区系和地理气候变迁等探讨琴叶风吹楠遗传多样性空间分布式样的成因和物种迁移。研究结果将为学术研究、资源保护、良种培育和开发利用提供依据。

琴叶风吹楠（Horsfieldia pandurifolia）是典型热带分布树种，云南热带雨林有野生，是特种油料资源植物，一直以来作为云南特有种记录，由于多种原因使得种群数量锐减，已被列入《中国物种红色名录》。另一方面，研究基础薄弱，其分类学位置一直存在争议，对其种内遗传变异也知之甚少，对种质资源保护、利用和学术交流带来诸多不便。本研究工作针对云南野生琴叶风吹楠开展群体变异的研究，再结合肉豆蔻科其它属种，从形态学、油脂化学和分子遗传学方面分析，处理琴叶风吹楠的分类学位置。研究结果表明：琴叶风吹楠种仁含油率52.48% -71.09%，十四碳酸相对含量约为88.14%-92.82%，其中十四碳烯酸为15.60% - 27.21%，十四烷酸为60.93% - 76.58%，油脂具良好化学稳定性，有特殊工业用途；风吹楠种子仁含油率为40.97% - 61.99%，十二烷酸为43.64% - 52.12%，十四烷酸为38.53% - 47.47%；大叶风吹楠种仁含油率为31.20% - 71.97%，十二烷酸为35.68% - 50.27%，十四烷酸为41.39% - 55.30%；云南肉豆蔻种仁含油率为5.54% - 14.83%，十四烷酸为53.58% - 62.52%，十六烷酸为10.79% - 14.07%，十八碳烯酸为15.04% - 19.06%；红光树属的含油率较低，十四烷酸为18.74% - 58.64%，十六烷酸为5.42% - 16.47%，十八碳烯酸为30.05% - 59.12%；琴叶风吹楠油脂肪酸组成种内变异极小，形态变异较大。结合形态学、油脂化学、分子系统学、植物地理学分析，琴叶风吹楠应从风吹楠属中分出来另建一属，支持de Wilde的处理，即将琴叶风吹楠H. pandurifolia并入H. macrocoma，然后将H. macrocoma再分出来建立Endocomia（内毛楠属）。因此建议将琴叶风吹楠更名为：“云南内毛楠Endocomia macrocoma (Miq.) de Wilde ssp. prainii (King) de Wilde”，不能记为云南特有种，在中南半岛有分布。琴叶风吹楠在物种水平的多态性较高，多态性率为75.16%，在居群水平，其平均多态性率为36.20%。