The evolution of fertilization modes independent of the micropyle in Fagales and 'pseudoporogamy'

In contrast to a majority of angiosperms showing porogamous fertilization, several fagalean families such as Betulaceae and Casuarinaceae are known to show chalazogamy, where fertilization is effected by a pollen tube passing through the chalaza instead of the micropyle. Our developmental study of p...

Full description

Saved in:
Bibliographic Details
Published in:Plant systematics and evolution 2006-05, Vol.259 (1), p.73-80
Main Authors: Sogo, A., Tobe, H.
Format: Article
Language:English
Subjects:
Angiosperms
Embryo sac
Evolution
Fagales
Fertilization
Integument
Mapping
Megaspores
Ovaries
Ovules
Phylogenetics
Phylogeny
Pistils
Plant growth
Pollen
Pollen tubes
Tubes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In contrast to a majority of angiosperms showing porogamous fertilization, several fagalean families such as Betulaceae and Casuarinaceae are known to show chalazogamy, where fertilization is effected by a pollen tube passing through the chalaza instead of the micropyle. Our developmental study of pollen-tube growth in pistils of Myrica rubra (Myricaceae, Fagales) further shows that pollen tubes reached the nucellus before the micropyle is formed by the integument. Since fertilized ovules appeared as if the pollen tube had passed through the micropyle for fertilization, we propose the new term 'pseudoporogamy' to this mode. By mapping diverse modes of fertilization, dependent or independent of the micropyle, onto a phylogenetic tree of Fagales, it appears that fertilization mode evolved from porogamy to chalazogamy and then further from chalazogamy to pseudoporogamy. Possible reasons for the evolution of fertilization modes independent of the micropyle in Fagales are discussed.
ISSN:0378-2697
1615-6110
2199-6881
DOI:10.1007/s00606-006-0409-x