Wentworth J E, Gornall R J
CMBRU, University of East London, Stratford, London, El 2 4LZ, UK.
Department of Botany, University of Leicester, Leicester, LEI 7RH, UK.
New Phytol. 1996 Dec;134(4):641-648. doi: 10.1111/j.1469-8137.1996.tb04929.x.
Diploid populations of Parnassia palustris L. var. palustris and var. condensata Travis & Wheldon have a highly symmetrical karyotype, consisting of seven metacentrk and two submetacentric chromosomes. The gross morphology of the karyotype of tetraploid populations is indistinguishable from that of the diploids. Studies of meiosis in tetraploids of both varieties demonstrated a high frequency of quadrivalent formation, strongly suggesting an autopolyploid origin. Later stages of meiosis in the tetraploids are regular and the pollen shows no decrease in stainability compared with that of the diploids. Some evidence is presented to show that tetraploids of both varieties may have a wider ecological amplitude than do diploids.
沼泽梅花草（Parnassia palustris L.）变种沼泽梅花草和变种密花梅花草的二倍体群体具有高度对称的核型，由七条中着丝粒染色体和两条亚中着丝粒染色体组成。四倍体群体核型的总体形态与二倍体无法区分。对两个变种四倍体减数分裂的研究表明，四价体形成的频率很高，强烈表明其起源为同源多倍体。四倍体减数分裂的后期是正常的，并且与二倍体相比，花粉的可染性没有降低。有证据表明，两个变种的四倍体可能比二倍体具有更广泛的生态幅度。
