Cytological and Embryological Studies on Apospory in Bothriochloa ischaemum L.
Cytological and embryological studies on apomictic species Bothriochloa ischaemum L. were carried out. Our studies revealed that the chromosome number of its root apical cells was 40, indicating that it was a tetraploid cytotype. During the stage of microsporogenesis, meiosis seemed irregular, as the pairing chromosome number of microspore mother cell was more than 20. It was often found that some chromosomes did not assemble in the equatorial plane or moved to the two poles of the cell, a few laggards were seen. Multiporate pollens (22.3%) were often observed. The studies showed that a high frequency (87.8%) of 1–3 or more aposporous embryo sacs developed in one ovule of the species. The mature aposporous sac was usually characterized by an egg cell and one polar nucleus. The egg cell could develop spontaneously into a large proembryo (100–200 μm) mass prior to anthesis. When several aposporous sacs occurred in the same ovule, usually 2 aposporous sacs were involved in pseudogamy and developed into separate endosperm masses in the same ovary. In the low frequency of mature seed, 13.5% twin-embryo seedlings could be obtained after mature seeds germinated.
KeywordsBothriochloa ischaemum L. apospory pseudogamy cytology embryology
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The support by Program of Guangdong Digital Botanical Garden and the Tropical and Subtropical Plant Germplasm Construction in Guangdong Province 2005B60301001 is greatly acknowledged and article has been reviewed by an Australia scientist Dr. Eric Bunn in Kings Park and Botanic Garden was also acknowledged.
- 1.Asker, S. E., Jerling, L. (1992) Apomixis in Plants. CRC Press, London, pp. 100–190.Google Scholar
- 2.Bashaw, E. C., Hanna, W. W. (1990) Apomictic reproduction. In: Chapman, G. P. (ed.) Reproductive Versatility in the Grasses. Cambridge University Press, Cambridge, pp. 100–130.Google Scholar
- 6.Cai, X., Mu, X. J., Zhu, Z. Q., Hua, Z. M. (1997) Poly-embryony and multiple seedlings in the apomictic plants. Acta Bot. Sin. 39, 590–595.Google Scholar
- 8.Celarier, R. P., Harlan, J. R. (1957) Apomixis in Bothriochloa, Dichanthium and Capillipedium. Phytomorph. 7, 93–102.Google Scholar
- 10.Chapman, G. P. (1992) Grass Evolution and Domestication. Cambridge University Press, Cambridge, pp. 138–155.Google Scholar
- 11.Chen, S. L. (ed.) (1997) Flora Reipublicae Popularis Sinicae. 10(2). Science Press, pp. 143–145.Google Scholar
- 12.Christov, M. A., Moskova, R. (1972) The apomixis and the polyembryony in Bothriochloa ischaemum L. Genetika Selek. 5, 71–86.Google Scholar
- 13.Coleman, S. W., Taliaferro, C. M., Tyrl, R. J. (2004) Old World Bluestems. Warm Season Grasses. American Society of Agronomy, Madison, WI, pp. 909–936.Google Scholar
- 14.Czapik, R. (2000) Apomixis in monocotyledons. In: Jacobs, S. W. L., Everett, J. (eds) Grasses: Systematics and Evolution. CSIRO, Kerenhaven, pp. 316–321.Google Scholar
- 18.Heslop-Harrison, J. (1961) The function of the glume pit and the control of cleistogamy in Bothriochloa docipiens (Hack). Phytomorph. 11, 378–383.Google Scholar
- 19.Ma, G. H., Zhao, N. X., Huang, X. L. (2001) Apomixis in the Gramineae. J. Trop. Subtrop. Bot. 9, 83–92.Google Scholar
- 20.Ma, G. H., Zhao, N. X., Huang, X. L. (2003) Facultative apospory in titraploid Paspalum distichum L. J. Trop. Subtrop. Bot. 11, 255–259.Google Scholar
- 22.Nakagawa, H. (1990) Embryo sac analysis and crossing procedure for breeding apomictic Guineagrass (Panicum maximum Jacq). Japan Agri. Res. Quart. 24, 163–168.Google Scholar
- 26.Wen, X. S., Ye, X. L., Li, Y. Q., Chen, Z. L. (1998) Embryological studies on apomixes in Pennisetum squamulatum. Acta Bot. Sin. 40, 598–604.Google Scholar
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