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RE‐EVALUATING THE SIGNIFICANCE OF CORRELATIONS BETWEEN SEED NUMBER AND SIZE: EVIDENCE FROM A NATURAL POPULATION OF THE LILY, CLINTONIA BOREALIS
Author(s) -
Galen Candace,
Weger Harold G.
Publication year - 1986
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.1537-2197.1986.tb12047.x
Subject(s) - selfing , biology , outcrossing , pollination , self pollination , population , natural population growth , botany , horticulture , pollen , demography , sociology
The basis for the negative correlation between seed number and seed size was experimentally investigated in a natural population of Clintonia borealis. Clones of this species vary significantly in estimated self‐compatibility (ratio of seed set with selfing to that with outcrossing) and this appears to affect the number and size of seeds set in individual flowers of each. Clones estimated to be largely self‐compatible set more seeds per flower than incompatible ones under natural pollination. However, naturally pollinated flowers of self‐compatible clones set smaller seeds than those of incompatible clones, and the significance of the negative relationship between seed number and size in individual flowers was removed by holding variation due to compatibility constant. Supplementing resources per flower (by reducing the number of fruits competing for resources per stem) significantly increased total seed mass but had no effect on the negative relationship between seed number per flower and seed size. In contrast, supplementing cross pollination did not significantly influence total seed mass per flower but changed the relationship between seed number and size to positive, regardless of resource level. In other words, with plentiful cross pollination maternal genets capable of setting more seeds per flower also produced heavier ones. Thus, evidence is provided that the balance between seed number and seed size in this population is regulated by the interaction of maternal self‐compatibility with natural pollination.