【作者】 张浩；

【导师】 刘占林； 赵桂仿；

【作者基本信息】 西北大学 ， 植物学， 2008， 硕士

【摘要】 巴山松(Pinus henryi Mast.)是我国秦巴山区特有种,主要分布于大巴山脉、巫山支脉以及云贵高原延伸的余脉上,但数量稀少,已被列为珍稀植物。分类上巴山松常作为油松或马尾松变种处理,个别专家将其认作独立种。在地理分布上,巴山松北与形态难以区分的油松相连,东与容易混淆的黄山松比邻,南与云南松交错,又与马尾松重叠分布(马尾松分布海拔更低)。形态特征的相似、分布的重叠以及杂交现象的存在都说明巴山松及其近缘种存在目前尚未清楚的复杂的种间关系。本研究用分子系统学方法为巴山松及与其近缘种(油松、马尾松、云南松、黄山松)的系统关系寻找证据。考虑到单个基因序列所提供的信息往往有限,而且利用编码的基因(演化速率往往较慢)在解决演化快的物种间的亲缘关系时效果往往较差,因此我们同时分析了基因组编码基因和演化速率较快的的非编码DNA序列,包括cpDNA(matK,rbcL,rpl20-rps18,trnV,rpoC2-rps2,psaB-prs14 and rrn5-trnN)、mtDNA(nad1,nad5,matR,SSU rRNA)和nDNA(ifg1934)基因组在内的12种DNA序列,以此来为巴山松及与其近缘种的关系及分类提供分子方面的证据。研究结果表明:(1)巴山松与油松、云南松、黄山松和马尾松等四种松树所处类群不同,因此作为油松或者马尾松变种的处理是不合适的,应视为独立种为宜。(2)在巴山松及其近缘种中,马尾松与其他松树的亲缘关系较远,而巴山松与黄山松、油松、云南松的之间的相互关系较近,其中油松和云南松的亲缘关系最近,巴山松、黄山松、云南松与油松分别向着不同的方向分化。(3)利用分子钟及其改进方法对巴山松及其近缘种的起源和分化时间进行了估测,发现马尾松是这几个近缘种中分化最早的一个类群,在2800万年前的渐新世(Oligocene epoch)的时候已经分化出来,但一直进化缓慢,因此拥有更多的祖先类型的基因组成。巴山松和黄山松分别在970万年前和690万年前中新世后期(Miocene epoch)分化出来,而油松和云南松则在最近的340万年前上新世(Pliocene epoch)才分化出来。松属植物分化时间较晚以及频繁的种间杂交可能是造成其种间关系不清的现象的主要原因。更多还原

【Abstract】 Pinus henryi Mast.,an endemic pine in China,mainly distributes over Daba mountains,Wushan mountains and offshoots of YunGui plateau.Most forest of P.henryi has been destroyed by man and this species is listed as rare plant.P.henryi is often regarded as taxonomic variant species of P.tabuliformis or P.massoniana.Several experts argued that it should be independent species based on the differences of timber anatomy and chemical components.According to geographic distribution,P.henryi is linked together with P.tabuliformis in north,neighbors with P.hwangshanensis in east,crisscrosses with P.yunnanensis in south,and overlaps with P.massoniana(lower at altitude).Complicated relationships exist in P.henryi and its relative species due to similar morphic characteristics,overlapped distribution and extended hybridization in pines.Considered that less information would be supplied by single DNA fragment,the phylogeny and evolutionary history of P.henryi and it relative species were explored using twelve DNA fragments from chloroplast(matK, rbcL,rpl20-rps18,trnV,rpoC2-rps2,psaB-prs14 and rrnS-trnN),mitochondrial (nad1,nad5,matR,ssu rRNA)and nuclear genomes(ifg1934).The results indicated that:Firstly,according to the different charactistics compared with it relative species,P.henryi should be regarded as a seperate species rather than taxonomic variant species of P.tabuliformis or P.massoniana.Secondly, P.henryi as an independent species is close to P.hwangshanensis,P.tabuliformis and P.yunnanensis and far from P.massoniana,P.tabuliformis and P.yunnanensis have closer relationships than the others.Thirdly,using molecular dating approaches,we estimated that P.massoniana origined foremost at Oligocene epoch about 28 million years ago(MYA),and it owns more archaic genetic components because of its slow evolutionary rate;P.henryi and P.hwangshanensis diverged later at Miocene epoch about 9.7MYA and 6.9MYA relatively;and a divergence time of Pliocene epoch 3.4MYA is obtained for P.tabuliformis and P.yunnanensis.Late divergent time and frequent gene flow might contribute to phenomena of the shared genomes in P.henryi and it relatives.更多还原