Analysis on the character evolution in Australian Gnaphalieae based on molecular phylogenetic tree.

测定了麻蝇科30属75种112个居群和麻蝇科3属6种8个居群的染色体数目。虽然澳大利亚以外的Gnaphalieae在x=7上的染色体碱基数是恒定的，但在澳大利亚半沙漠中发现了anganthus （n=13,12,6）、Asteredia （n=9,7）、Erymophyllum （n=14,11）、Gnephosis （n=11,8）、Hyaloserma （n=12,11,8）、Lawrencella （n=11,8）、Millotia （n=13,11,8）、Myriocephalus （n=14,11）、Podolepes （n=12,11,10,8,7,3）、Pogonolepis （n=6,5,4）、Polycalymma （n=14,8）、Pycnosorus （n=10,6）、Rhodanthe （n=11,10,8,7,5）和Tricanthodium （n=4,3）的变异倍体异常序列。为了弄清葡萄属植物的种间关系及染色体数目习性和形态特征的进化趋势，我们比较了葡萄属植物叶绿体matK基因的核苷酸序列，构建了葡萄属植物的分子系统发育树。matK树支持Podolepis属的单系性，除了P.kendallii曾被分类在herychryaceae中。根据其生长习性的不同，将其分为多年生和一年生两类。异倍体从n=12减少到n=3，发生在两个分支中，这些衍生的性状被认为是适应干旱或季节性干旱条件的。

Chromosome numbers from 112 populations of 75 species of 30 genera in Gnaphalieae and 8 populations of 6 species of 3 genera in Plucheeae were determined. Although the chromosome base number of Gnaphalieae outside of Australia is constant on x=7, the variable dysploidy series in Angianthus (n=13,12,6), Asteredia (n=9,7), Erymophyllum (n=14,11), Gnephosis (n=11,8), Hyaloserma (n=12,11,8), Lawrencella (n=11,8), Millotia (n=13,11,8), , Myriocephalus (n=14,11), Podolepes (n=12,11,10,8,7,3), Pogonolepis (n=6,5,4), Polycalymma (n=14,8), Pycnosorus (n=10,6), Rhodanthe (n=11,10,8,7,5) and Tricanthodium (n=4,3) were found in Australian semi-desert. To clarify the species relationship and the evolutionary trends in chromosome number habit and morphological characters, we have compared the nucleotide sequences of matK gene of chloroplast between species and constructed the molecular phylogenetic trees of Grapharieae. The matK tree supports the monophyly of the genus Podolepis, except P.kendallii which has onece classified in Herychrysum. The genus Podolepis is divided into 2 clusters corresponding to the difference of habits, perennial and annual. The dysploid reductions from n=12 to n=3, have occurred in two clades and these derived characters are regarded to be adaptive under the arid or seasonally dry conditions.