Lim Wan Li, Loh Chiang Shiong
Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.
New Phytol. 2003 Jul;159(1):279-287. doi: 10.1046/j.1469-8137.2003.00797.x.
• Occurrence of endopolyploidy in somatic tissues of the hybrid orchid Vanda Miss Joaquim (Vanda hookeriana × Vanda teres) was investigated with respect to tissue type and developmental stage. Effects of naphthaleneacetic acid (NAA) and gibberellic acid (GA ) on endopolyploidy during embryo development were also studied. • For the study of endopolyploidy, flow cytometric analysis was employed to determine nuclear DNA content of cells of somatic tissues. • Multiploid cells were observed in leaves, roots and column, but not in shoot apex, stem, perianth and pedicel. Furthermore, differential distribution of multiploid cells was found among different parts of leaves and roots. The degree of endopolyploidy in embryos increased with development. NAA was shown to induce endoreduplication in germinating embryos to a much larger extent than GA . • The pattern of endopolyploidy was characteristic of tissue type and developmental stage. The implications of endopolyploidy during differentiation and development, as well as the relevance of endopolyploidy to somaclonal variation, are discussed.
• 针对杂交兰花卓锦万代兰（Vanda hookeriana × Vanda teres）体细胞组织中的核内多倍体现象，研究了其组织类型和发育阶段。还研究了萘乙酸（NAA）和赤霉素（GA）对胚胎发育过程中核内多倍体的影响。
• 为研究核内多倍体，采用流式细胞术分析来测定体细胞组织细胞的核DNA含量。
• 在叶片、根和蕊柱中观察到多倍体细胞，但在茎尖、茎、花被和花梗中未观察到。此外，在叶片和根的不同部位发现了多倍体细胞的差异分布。胚胎中的核内多倍体程度随发育而增加。结果表明，NAA比GA在更大程度上诱导萌发胚胎中的核内复制。
• 核内多倍体模式具有组织类型和发育阶段的特征。讨论了核内多倍体在分化和发育过程中的意义，以及核内多倍体与体细胞克隆变异的相关性。
