Description of a fertilization-independent obligate apomictic species: Corunastylis apostasioides Fitzg.
Sex Plant Reprod
; 22(3): 153-65, 2009 Sep.
Article
em En
| MEDLINE
| ID: mdl-20033436
ABSTRACT
The Australian midge orchid Corunastylis apostasioides of the tribe Diurideae has completely eliminated any male contribution in the process of seed formation, which occurs directly from the maternal tissue by a process termed apomixis. Here, we report C. apostasioides to be an obligate apomictic species devoid of any sexuality and compare its development to a close sexual relative C. fimbriata (R. Br.) D.L. Jones & M.A. Clem. Apomictic characteristics in C. apostasioides include production of seed in absence of fertilization, frequently closed flowers, production of immature pollen in non-dehiscent anthers, expansion of ovaries despite the lack of fertilization and the absence of a citronella scent that is found in C. fimbriata produced to attract pollinating vinegar flies (Jones 2006). The nature of apomixis in C. apostasioides was examined by ovule histology and amplified fragment length polymorphism (AFLP) in each case drawing comparison with sexual C. fimbriata. In C. apostasioides the central megaspore mother cell undergoes diplosporic apomixis, while additional embryos are derived from nucellar or integument initials formed by sporophytic apomixis. Typical of apomicts, C. apostasioides is polyploid compared to the sexual C. fimbriata. The divergences of C. apostasioides from sexuality to apomictic development are discussed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Violaceae
/
Fertilização
Idioma:
En
Revista:
Sex Plant Reprod
Assunto da revista:
BOTANICA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Austrália