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VISCIN THREADS, POLLINATION EFFICIENCY AND LOW POLLEN‐OVULE RATIOS
Author(s) -
Cruden Robert William,
Jensen Kenneth G.
Publication year - 1979
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.1537-2197.1979.tb06295.x
Subject(s) - pollen , biology , pollinator , pollination , ovule , onagraceae , botany , pollen source
Some Onagraceae are characterized by quite low pollen‐ovule ratios. We suggest they are an evolutionary response to highly efficient pollination, mediated through viscin threads, which hold large numbers of pollen grains together, and by stigmas, which are large relative to the area of the pollinator over which the pollen is spread. The pollen grains of some Leguminosae are joined by “exinal connections” which are chemically and morphologically similar to viscin threads. In the legumes the area of the stigma is small relative to the area of pollen on the pollinator and pollination is facilitated by short connections which hold small numbers of pollen grains together.