Phylogeographical analysis on the Arisaema ovate group, a circum. Japan Sea element

通过对天南星属植物的分子遗传学研究，发现天南星属植物是一个单系类群。利用从整个地理范围内的各种种群收集的大量样本，对Glade（卵形天南星属）进行了深入的地理研究。在每个样品中，检查形态、染色体数目和叶绿体DNA（trnL-trnF、psbB-psbH、rpl 20-rpsl 2区域）中的序列变异。同时还分析了核DNA的部分区域，包括植物素B区。结果表明：1）卵圆天南星组为日本特有种;它不包括A。sachalinense和A. amurense. 2）A.卵圆组为二倍体（2n=26）、三倍体、四倍体、五倍体和六倍体。二倍体植物主要分布在太平洋地区，而四倍体植物则广泛分布在日本海沿岸地区。五倍体分布于青森县和北海道，六倍体分布于北海道。在所有的多倍体水平上都发现了A型。地方类型B、C、E、F仅见于四倍体。D型是A型特有的。4）四倍体的广泛分布不可能是多源的。为进一步研究多倍体的起源和基因流提供理论依据。卵圆形群光敏色素B基因可能是有用的。nagiense被描述为

A monophyletic Glade including Arisaema ovate was detected through molecular phylogeny on the wide samples of Arisaema. Intensive geographical studies were carried out on the Glade (the Arisaema ovate group) using mass samples collected from various populations throughout the geographical range. In each samples, morphology, chromosome numbers and sequence variation in the chloroplast DNA (trnL-trnF, psbB-psbH, rpl20-rpsl2 regions) were examined. Some regions of nuclear DNA including phytochlome B region were also analyzed. A phylogeographical consideration was made based on the results as follows:1) The Arisaema ovale group is endemic to Japan. It includes neither A. sachalinense nor A. amurense.2) The A. ovale group shows a series of polyploidy with diploid (2n=26), triploid, tetraploid, pentaploid and hexaploid. The diploid plants are distributed in the pacific regions, while tetraploid plants are widely distributed in the Japan Sea side regions. Pentaploids are in Aomori prefecture as well as Hokkaido, and hexaploids are endemic to Hokkaido.3) Six haplotypes were distinguished in the cpDNA sequence. The major type, Type A, was found in all the levels of polyploidy. Local Types, B, C, E, F, were found only in the tetraploids. Type D was specific to A. inaense, a diploid species.4) Multiple origin was not suggested for the widely distributed tetraploids. For further analysis to reveal the origin of polyploids and gene flow in the A. ovale group Phytochrome B gene may be useful.5) A new species, A. nagiense was described