title: The influence of herbivory on pre- and postzygotic stages of reproduction following open, self, and outcross pollination.
abstract: OBJECTIVE
  Herbivory affects pollination success and reproductive output in plants. However, the different stages in the process from pollination to seed maturation have hardly been investigated within the context of herbivory. Herbivory might affect these stages via its effect on geitonogamous pollination and thereby the proportion of self pollen delivered to the stigma and/or via its effect on the nutritional capacity of the maternal plant.
  
  
  METHODS
  Plants of monocarpic Cynoglossum officinale were experimentally subjected to root herbivory and exposed to natural open pollination in combination with self and outcross hand pollination. We quantified pollen germination, pollen tube competition intensity, pollen tube attrition, fruit set, and seed initiation, abortion, and maturation.
  
  
  RESULTS
  Although root herbivory did not affect pollen germination or pollen tube attrition, fruit set and seed initiation and maturation were negatively affected by herbivory, but for seed initiation only in the case of outcross- and open-pollinated flowers. The intensity of pollen tube competition positively affected seed initiation, but only in plants infested with the herbivore.
  
  
  CONCLUSIONS
  Our study demonstrates that herbivory did not affect the early stages following pollination, but significantly impacted later postpollination stages such as fruit set and seed maturation and selection based on pollen tube competition intensity on zygote development. Our findings suggest that decreased nutritional capacity of the mother plant in response to root herbivory rather than herbivory effects on pollen quality was responsible for the lower fruit and seed production in infested plants.
authors.affiliation: Terrestrial Ecology Unit, Biology Department, Ghent University, K. L. Ledeganckstraat 35, BE-9000 Ghent, Belgium Celine.Ghyselen@UGent.be.
authors.forename: Céline
authors.initials: C
authors.lastname: Ghyselen
authors.affiliation: Terrestrial Ecology Unit, Biology Department, Ghent University, K. L. Ledeganckstraat 35, BE-9000 Ghent, Belgium.
authors.forename: Dries
authors.initials: D
authors.lastname: Bonte
authors.affiliation: Division of Plant Ecology and Systematics, Biology Department, University of Leuven, Kasteelpark Arenberg 31, BE-3001 Leuven, Belgium Research Institute for Nature and Forest, Kliniekstraat 25, BE-1070 Brussels, Belgium.
authors.forename: Rein
authors.initials: R
authors.lastname: Brys
mesh_terms: D000818:Animals; D028082:Boraginaceae / Q000502:physiology*; D060434:Herbivory; D018517:Plant Roots / Q000502:physiology; D054817:Pollination; D012098:Reproduction; D048889:Weevils / Q000502:physiology*
keywords: Boraginaceae; Cynoglossum officinale; Mogulones cruciger; pollen germination; geitonogamy; pollen tube attrition; pollen tube competition; pollination; root herbivory; seed abortion; self pollination