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EVOLUTIONARY AND ECOLOGICAL SIGNIFICANCE OF STARCH STORAGE IN POLLEN OF THE ARACEAE
Author(s) -
Grayum Michael H.
Publication year - 1985
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.1537-2197.1985.tb08420.x
Subject(s) - pollen , araceae , biology , botany , genus , starch , pollinator , pollination , biochemistry
Starch content was qualitatively assessed for pollen of 79 of the 111 currently recognized genera of the family Araceae—one of three monocot families known to exhibit both starchy and starchless pollen. Although 73% of the genera investigated had exclusively starchy pollen, character correlation suggests that starchless pollen is the primitive type for the family Araceae, as well as for monocots in general. Pollen starch content is a highly conservative character at the generic level in Araceae; only a single genus ( Schismatoglottis ) clearly exhibits both character states. The distribution of starchy pollen among aroid genera is consistent with what have here been termed Bakers' Starch Laws. Aroid pollen below a certain critical diameter—17‐25 μm—is almost invariably starchless. Larger pollen is nearly always starchy, except where insect pollinators may use pollen nutritionally. There is strong evidence that the trend from starchless to starchy pollen in Araceae is reversible, according to the constraints imposed by the aforementioned factors.