The reproductive ecology of island populations of distylous Menyanthes trifoliata (Menyanthaceae)

@article{citeulike:1038162, abstract = {Menyanthes trifoliata L. is a distylous, clonal aquatic macrophyte found in shallow bogs and river margins throughout the boreal ecosystem, including the island of Newfoundland. A combination of long-distance dispersal and colonization after deglaciation, and pollen limitation resulting from reduced pollinator diversity and abundance documented on islands, predicts the breakdown of heterostyly to favour the establishment of self-compatible homostyles on islands. To test if self-fertilizing homostyles have been selected, variation in floral characters and compatibility relationships were examined in M. trifoliata populations from the Avalon Peninsula of Newfoundland. Morph ratio and its effect on fruit and seed set were examined in nine populations. Of the seven dimorphic populations, morphs occurred in a 1:1 ratio in four populations and deviated significantly from a 1:1 ratio in three populations. The two populations monomorphic for either pin or thrum morphs set few fruits or seeds (<15\%). A strictly reciprocal arrangement of stigma height and anther length was not observed between pin and thrum morphs in the majority of populations studied. Stigma-anther separation showed a bimodal distribution with few intermediate "homostylous" flowers, rather than the discreet bimodal distribution typical of distylous species. Fruit and seed set were high (>60\%) in equal morph ratio populations and were not significantly correlated to stigma-anther separation, indicating that there was no selective advantage of being homostylous. All three populations tested were highly self-incompatible, confirming that there has not been a breakdown of heterostyly on the island of Newfoundland. A reduced pollinator fauna typical of island environments may have relaxed stabilizing selection for strict herkogamy between floral morphs, resulting in the observed lack of reciprocity. Key words: Menyanthes trifoliata, distyly, homostyle, reciprocal herkogamy, clonal aquatic macrophyte, island of Newfoundland.}, author = {Thompson, Faye L. and Hermanutz, Luise A. and Innes, David J. }, citeulike-article-id = {1038162}, editor = {Can}, journal = {Canadian Journal of Botany}, keywords = {heterostyly, islands, morphology, plant}, month = {May}, number = {5}, pages = {818--828}, posted-at = {2007-01-12 14:05:54}, priority = {3}, title = {The reproductive ecology of island populations of distylous Menyanthes trifoliata (Menyanthaceae)}, url = {http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?journal=cjb\&\#38;volume=76\&\#38;year=1998\&\#38;issue=5\&\#38;msno=b98-059\&\#38;calyLang=eng}, volume = {76}, year = {1998} }

TY - JOUR ID - citeulike:1038162 L3 - citeulike-article-id:1038162 N2 - Menyanthes trifoliata L. is a distylous, clonal aquatic macrophyte found in shallow bogs and river margins throughout the boreal ecosystem, including the island of Newfoundland. A combination of long-distance dispersal and colonization after deglaciation, and pollen limitation resulting from reduced pollinator diversity and abundance documented on islands, predicts the breakdown of heterostyly to favour the establishment of self-compatible homostyles on islands. To test if self-fertilizing homostyles have been selected, variation in floral characters and compatibility relationships were examined in M. trifoliata populations from the Avalon Peninsula of Newfoundland. Morph ratio and its effect on fruit and seed set were examined in nine populations. Of the seven dimorphic populations, morphs occurred in a 1:1 ratio in four populations and deviated significantly from a 1:1 ratio in three populations. The two populations monomorphic for either pin or thrum morphs set few fruits or seeds (<15%). A strictly reciprocal arrangement of stigma height and anther length was not observed between pin and thrum morphs in the majority of populations studied. Stigma-anther separation showed a bimodal distribution with few intermediate "homostylous" flowers, rather than the discreet bimodal distribution typical of distylous species. Fruit and seed set were high (>60%) in equal morph ratio populations and were not significantly correlated to stigma-anther separation, indicating that there was no selective advantage of being homostylous. All three populations tested were highly self-incompatible, confirming that there has not been a breakdown of heterostyly on the island of Newfoundland. A reduced pollinator fauna typical of island environments may have relaxed stabilizing selection for strict herkogamy between floral morphs, resulting in the observed lack of reciprocity. Key words: Menyanthes trifoliata, distyly, homostyle, reciprocal herkogamy, clonal aquatic macrophyte, island of Newfoundland. IS - 5 JF - Canadian Journal of Botany EP - 828 TI - The reproductive ecology of island populations of distylous Menyanthes trifoliata (Menyanthaceae) VL - 76 SP - 818 KW - heterostyly KW - islands KW - morphology KW - plant AU - Thompson, Faye AU - Hermanutz, Luise AU - Innes, David A2 - Can PY - 1998/05// UR - http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?journal=cjb&#38;volume=76&#38;year=1998&#38;issue=5&#38;msno=b98-059&#38;calyLang=eng ER -