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Seed fertilization, development, and germination in Hydatellaceae (Nymphaeales): Implications for endosperm evolution in early angiosperms
Author(s) -
Rudall Paula J.,
Eldridge Tilly,
Tratt Julia,
Ramsay Margaret M.,
Tuckett Renee E.,
Smith Selena Y.,
Collinson Margaret E.,
Remizowa Margarita V.,
Sokoloff Dmitry D.
Publication year - 2009
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.0900033
Subject(s) - endosperm , haustorium , biology , botany , ovule , double fertilization , pollination , ecology , host (biology) , pollen , pollen tube
New data on endosperm development in the early‐divergent angiosperm Trithuria (Hydatellaceae) indicate that double fertilization results in formation of cellularized micropylar and unicellular chalazal domains with contrasting ontogenetic trajectories, as in waterlilies. The micropylar domain ultimately forms the cellular endosperm in the dispersed seed. The chalazal domain forms a single‐celled haustorium with a large nucleus; this haustorium ultimately degenerates to form a space in the dispersed seed, similar to the chalazal endosperm haustorium of waterlilies. The endosperm condition in Trithuria and waterlilies resembles the helobial condition that characterizes some monocots, but contrasts with Amborella and Illicium , in which most of the mature endosperm is formed from the chalazal domain. The precise location of the primary endosperm nucleus governs the relative sizes of the chalazal and micropylar domains, but not their subsequent developmental trajectories. The unusual tissue layer surrounding the bilobed cotyledonary sheath in seedlings of some species of Trithuria is a belt of persistent endosperm, comparable with that of some other early‐divergent angiosperms with a well‐developed perisperm, such as Saururaceae and Piperaceae. The endosperm of Trithuria is limited in size and storage capacity but relatively persistent.