若干铁杉属植物核型的比较研究

本文首次报道了我国特产的重点保护植物南方铁杉的核型,全由中部和近中部着丝点染色体构成,核型公式为K(2n)=2x=24=20m+4sm,属“ 2A”类型。染色体的相对长度组成为2n=24=12M_2+10M_1+2S。通过比较。发现东亚的南方铁杉的核型与台湾铁杉甚为相似而略具进化的趋势,但北美东部的卡罗来纳铁杉的核型比它们进化得多。本文支持Florin认为铁杉属至少在早第三纪存在一条从欧亚大陆经过白令海峡到达北美洲的迁移路线的意见。

THE COMPARATIVE KARYOTYPIC STUDIES IN SOME SPECIES OF TSUGA (PINACEAE)THE COMPARATIVE KARYOTYPIC STUDIES IN SOME SPECIES OF TSUGA (PINACEAE)

The present paper deals with the karyotype analysis of Tsuga chinensis(Franch.)Pritz.Tar.tchekiangensis(Flous)Cbeng et L.K.Fu,which is the priority for conservation plant in our country and endemic to China for the first time.The somatic chromosomes in rcot-tip cells of the plant are found to be 2n=24,all with median and ubmedian constrictions According to the terminology defined by Lev-an et al.[7],the karyotypic formula is K(2n)=2x=20m+4sm,which belongs to "2A" of Stebbins[10,11] karyotypic symmetry and is 2n=24=12M2+10M1+2S according to the standard defined by Kuo et al[8] based on relative length.By the comparative studies,the author found that the karyotype of the plant was very similar to that of Tsuga formosana Hayata distributed in Eastern Asia and had an advanced trend,but they were much primodialer than that of Tsuga caroliniana Engelmann which distributed in Eastern North America.The result supported Florin's[5] opinion that the oldest remains of Eocene age in the Maritime province of Siberia hinted at the existence of at least one migration route for Tsuga between Eurasia and North America in the early Tertiary,viz,across Ber-ingia.The present paper deals with the karyotype analysis of Tsuga chinensis(Franch.)Pritz.Tar.tchekiangensis(Flous)Cbeng et L.K.Fu,which is the priority for conservation plant in our country and endemic to China for the first time.The somatic chromosomes in rcot-tip cells of the plant are found to be 2n=24,all with median and ubmedian constrictions According to the terminology defined by Lev-an et al.[7],the karyotypic formula is K(2n)=2x=20m+4sm,which belongs to "2A" of Stebbins[10,11] karyotypic symmetry and is 2n=24=12M2+10M1+2S according to the standard defined by Kuo et al[8] based on relative length.By the comparative studies,the author found that the karyotype of the plant was very similar to that of Tsuga formosana Hayata distributed in Eastern Asia and had an advanced trend,but they were much primodialer than that of Tsuga caroliniana Engelmann which distributed in Eastern North America.The result supported Florin's[5] opinion that the oldest remains of Eocene age in the Maritime province of Siberia hinted at the existence of at least one migration route for Tsuga between Eurasia and North America in the early Tertiary,viz,across Ber-ingia.