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The role of self‐pollen in the female reproductive success of common milkweed ( Asclepias syriaca : Asclepiadaceae)
Author(s) -
Morse Douglass H.
Publication year - 1994
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.1537-2197.1994.tb15450.x
Subject(s) - biology , clone (java method) , follicle , botany , genetics , gene
Follicle production from bagged hand‐pollinations of the largely self‐incompatible common milkweed ( Asclepias syriaca ) greatly exceeded that of open‐pollinated flowers by seven‐ to 30‐fold in certain clones, even though these clones received one to three natural pollinations per flower. To test the basis for this difference I performed an extensive set of cross‐ and self‐pollinations on the clone exhibiting the lowest natural follicle production, with additional experiments on other clones for comparison. Bagged, hand cross‐pollinations in the least productive clone produced seven to 20 times more follicles than unbagged, hand cross‐pollinations in that clone exposed to pollinating insects. Bagged flowers of this clone supplied with simultaneous hand, cross‐ and hand, self‐pollinations produced no follicles. One other clone that normally produced few follicles responded to bagged and unbagged, hand cross‐pollinations in a similar way, but follicle production of two heavier producing clones did not differ in response to this manipulation. These results suggest that self‐pollinations strongly reduce the success of cross‐pollinations in clones that normally experience low follicle production. Resource limitation cannot account for the low follicle production, because the stems readily supported additional follicles following supplemental hand pollinations.