Evidence for antheridogen production and its mediation of a mating system in natural populations of fern gametophytes
1977
TRYON, R.M. | VITALE, G.
Gametophytes of Asplenium pimpinellifolium Fee and Lygodium heterodoxum Kze., occurring as natural populations in Veracruz, Mexico, were studied with respect to their spacing, size, and number of antheridia and archegonia. Small gametophytes, 0.3-2.2 mm in width and growing in colonies, usually had high numbers of antheridia. Gametophytes of the same size, growing at least 1 5 cm from the nearest neighbour, had few antheridia. In the colonial gametophytes there was a strong correlation between heavily antheridiate ones and their proximity to large archegoniate gametophytes. The data are the first to suggest the presence of an antheridogen system operating in nature, with concomitant opportunities for cross-fertilization. The rôle of polyploidy in storing genetic variation and the rôle of antheridogen-mediated out-crossing in releasing variation are seen as co-adaptive phenomena in the ferns.
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