<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus <italic>Zamia</italic> is represented by a range of number from 2n=16-28. <italic>Ginkgo</italic>, <italic>Welwitschia</italic> and <italic>Gentum</italic> show 2n=24, 2n=42, and 2n=44 respectively. <italic>Ephedra</italic> shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for <italic>Pseudolarix</italic> and <italic>Pseudotsuga</italic> with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.</p></abstract>

The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.

Chromosome Numbers in Gymnosperms - An Update

Amity Institute of Biotechnology, Research Cell

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Chromosome Numbers in Gymnosperms - An Update"}

The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of...

Chromosome Numbers in Gymnosperms - An Update

Publié en ligne: 03 mars 2020

Pages: 13 - 19

DOI: https://doi.org/10.2478/sg-2020-0003

Mots clés
gymnosperms, chromosome numbers, polyploidy, B-chromosome, sex chromosomes

© 2020 Shubhi Rastogi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Chromosome Numbers in Gymnosperms - An Update

Publié en ligne: 03 mars 2020

Pages: 13 - 19

DOI: https://doi.org/10.2478/sg-2020-0003

Mots clésgymnosperms, chromosome numbers, polyploidy, B-chromosome, sex chromosomes

© 2020 Shubhi Rastogi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Mots clés
gymnosperms, chromosome numbers, polyploidy, B-chromosome, sex chromosomes