[目的]研究药用植物灵菊七(Gynura medica)的细胞染色体特点,并对其染色体核型进行分析.[方法]以灵菊七幼苗茎尖为材料,从上午6:30～10:30,每隔20 min取材一次,采用常规制片技术制片,显微镜观察中期分裂相细胞,对染色体完全分散开的细胞进行染色体计数及核型分析.[结果]在染色体分散良好的102个中期分裂相细胞中,有96.08％含20条染色体,3.92％含40条染色体；同时结果表明上午7:50～9:30取材较佳.[结论]G.medica为二倍体植物,体细胞含有10对染色体,核型公式为2n=2x=20 m,染色体核型属于1A型.该研究结果为国内首次报道.%[Objective] To study the chromosomal characteristics and karyotypes of G. medica[Method] Stem tip of G. medica seedlings rnwere collected every 20 rain from 6:30 to 10:30 am, and all materials were treated and squashed for investigating chromcsouud number and karyotypcs analysis. [Result] In tote/102 stem tip cells in metaphase, 96.08% of cells are with 20 chromosomes, and 3.92% of cells are with 40 chromosomes. The optimal time for sampling was from 7:50 to 9:30 am. [Conclusion] G. medica is the diploid plant with 20 chromo-somcs. Karyotype analysis gets formula 2n = 2x = 20 re,and all 10 pairs of chromosomes belong to type IA. The article reported the chromo-rnsomes characteristics of G. medica for the first time in China.
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