Chromosome number variation and polyploidy in 19 Kaempferia （Zingiberaceae） taxa from Thailand and one species from Laos  

作　　者：Nattapon Nopporncharoenkul Jatuporn Chanmai Thaya Jeniittikul Kesara Anamthawat-Jonsson Puangpaka Soontornchainaksaeng 

机构地区：[1]Department of Plant Science, Faculty of Science, Mahidol University, Bangkok 10400, Thailand [2]Institute of Life and Environmental Sciences, School of Engineering and Natural Sciences, University of Iceland, Askja, Sturlugata 7, Reykjavik IS-101, Iceland

出　　处：《Journal of Systematics and Evolution》2017年第5期466-476,共11页植物分类学报（英文版）

摘　　要：Several Kaempferia species, endemic to Thailand, are rare and therefore entitled to conservation status; other species are widely cultivated. We conducted extensive cytogenetic investigation of this genus to elucidate the botanical and taxonomic characterization of these plants. The study included 42 accessions belonging to 15 Kaempferia species and four undescribed taxa from regions throughout Thailand, and one species from Laos. We determined chromosome numbers from root-tip cells collected from germinating rhizomes ex situ, but examined meiosis in flowers collected from the wild. The mitotic analyses verify that 2n chromosome numbers range from 22 （diploid, 15 taxa）, 33 （triploid, three species）, 44 （tetraploid, five taxa） to 55 （pentaploid, one species）. Four taxa included accessions with different ploidy levels. The meiotic analyses demonstrated that all 14 diploid accessions investigated displayed normal meiosis, forming 11 bivalents, indicating the base chromosome number x = 11 for this genus. Meiotic figures were obtained from one triploid and four tetraploid accessions. The triploid showed 11 trivalents, most likely indicating autotriploidy. Two tetraploid accessions showed regular meiotic figures consisting of 22 bivalents, probably indicating allopolyploidy originating from interspeciflc hybrids, a hypothesis that is consistent with observations of plant morphology. The other two tetraploid accessions belong to the same species and show mostly irregular meiotic figures. Cytogenetic information is useful for evaluating fertility and hybridity in the genus. Good seed set was observed among diploid and tetraploid accessions. Triploid and pentapioid plants, on the other hand, do not set seeds, but produce large clusters of vegetatively-propagated rhizomes.Several Kaempferia species, endemic to Thailand, are rare and therefore entitled to conservation status; other species are widely cultivated. We conducted extensive cytogenetic investigation of this genus to elucidate the botanical and taxonomic characterization of these plants. The study included 42 accessions belonging to 15 Kaempferia species and four undescribed taxa from regions throughout Thailand, and one species from Laos. We determined chromosome numbers from root-tip cells collected from germinating rhizomes ex situ, but examined meiosis in flowers collected from the wild. The mitotic analyses verify that 2n chromosome numbers range from 22 （diploid, 15 taxa）, 33 （triploid, three species）, 44 （tetraploid, five taxa） to 55 （pentaploid, one species）. Four taxa included accessions with different ploidy levels. The meiotic analyses demonstrated that all 14 diploid accessions investigated displayed normal meiosis, forming 11 bivalents, indicating the base chromosome number x = 11 for this genus. Meiotic figures were obtained from one triploid and four tetraploid accessions. The triploid showed 11 trivalents, most likely indicating autotriploidy. Two tetraploid accessions showed regular meiotic figures consisting of 22 bivalents, probably indicating allopolyploidy originating from interspeciflc hybrids, a hypothesis that is consistent with observations of plant morphology. The other two tetraploid accessions belong to the same species and show mostly irregular meiotic figures. Cytogenetic information is useful for evaluating fertility and hybridity in the genus. Good seed set was observed among diploid and tetraploid accessions. Triploid and pentapioid plants, on the other hand, do not set seeds, but produce large clusters of vegetatively-propagated rhizomes.

关 键 词：ALLOPOLYPLOIDY AUTOPOLYPLOIDY chromosome number Kaempferia meiotic figure Zingiberaceae. 

分 类 号：Q943[生物学—植物学] S667.103.2[农业科学—果树学]