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Ovulate cone, pollination drop, and pollen capture in Sequoiadendron (Taxodiaceae)
Author(s) -
Takaso T.,
Owens J. N.
Publication year - 1996
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 - 10.1002/j.1537-2197.1996.tb13898.x
Subject(s) - ovule , pollination , bract , pollen , biology , botany , pollen tube , ultrastructure , drop (telecommunication) , telecommunications , inflorescence , computer science
In Sequoiadendron ovules are borne inside the ovulate cone, and pollination drops secreted from these ovules collect pollen. We examined: (1) the relation between ovular position and pollen capture; (2) pollen behavior when in contact with a pollination drop; and (3) ultrastructure of ovules during pollination drop secretion. During wet periods a water sheet forms on the surface of the cone due to bract shape and wettability. Pollination drops persist inside the wetted cone, and pollen capture resumes immediately after drying. Pollen landing on a pollination drop is taken inside the drop and carried into the micropyle when the drop contracts. Several notable ultrastructural features appear in the nucellus, integument, chalaza, and bract lamina during pollination‐drop secretion. The abaxial surface of the lamina is covered by a membrane that may contribute to the wettable nature of the surface.