オーストラリア半砂漠地域へのキク科植物の適応進化の解析

在9月21日至10月30日的野外考察期间，我们在维多利亚州、新南威尔士州、昆士兰州、北领地和南澳大利亚州采集了大约120个澳洲菊科（Asutralian Astereae）和Gnaphalieae种群样本，并调查了它们的栖息地状况。所有的藏品，除了捐赠给澳大利亚国家和国家Harbaria的标本外，都被带回日本，用于后续的研究。测定了麻蝇科23属68种103个居群和麻蝇科3属6种8个居群的染色体数目。尽管普氏科的基本染色体数x=10是保守的，但在Gnaphalieae中发现了常见的异倍体。分别为：Podolepis （n=12-3）、Pogonolepis （n=6-4）、Rhodanthe （n=11-5）、Tricanthodium （n=4-3）等。干旱地区的物种经常表现出一年生习性。为了明确物种间的物种关系以及适应澳大利亚干旱地区的染色体数目、习性和形态特征的进化趋势，我们比较了短掌藓叶绿体matK基因的核苷酸序列，构建了短掌藓的分子系统发育树。这两棵树是一致的，支持这些属的单系性。根据花药附属物和花柱的形态、地理分布和染色体数目的变异模式，将短苞花序分为4个簇。异倍体从n=9开始减少，习性从多年生到一年生的变化，果实形态从简单到复杂的变化是在几个独立的时期得出的，被认为是适应干旱或季节性干旱条件的。对澳洲蕨科7个近缘属68个分类群和8个种进行了核型分析。

We have collected about 120 population samples of Asutralian Astereae and Gnaphalieae and investigated their habitat condition during the field expeditions (from Sept.21 to Oct.30 for Victoria, New South Wales, Qeensland, Northern Territory and South Australia). All of collections, except the donating speciments to Australian State and National Harbaria, have been brought back to Japan and served to the following researches. Chromosome numbers from 103 populations attributed 68 species of 23 genera of Gnepharieae and from 8 populations attributed 6 species of 3 genera of Pulcheeae were determined. The frequent dysploidy has been found in Gnaphalieae although the basic chromosome number x=10 is conservative in Pulcheeae. They are in Podolepis (n=12-3) , Pogonolepis (n=6-4) , Rhodanthe (n=11-5) , Tricanthodium (n=4-3) and so on. Species of arid regions frequently display an annual habit. To clarify the species relationship between species and the evolutionary trends in Chromosome number, habit and morphological characters adapting to the Australian arid regions, we have compared the nucleotide sequence of matK gene of chloroplast and constructed the molecular phylogenetic trees in Brachyscome. Both trees are consistent the support the monophyly of these genera. Brachyscome is divided into 4 clusters corresponding to the morphology of anther appendage and style, geographical distribution and the variation pattern of chromosome number. The dysploid reductions from n=9, the change of habit from perennial to annual and the change of fruit morphology from simple to complex have been derived in several independent leneages and are regarded to be adaptive in arid or seasonally dry conditions. Karyotype analyzes were made on 68 taxa of Brachyscome and 8 species of 7related Australian Astereae genera.