Journal Article

Outbreeding and inbreeding strategies in herbaceous-shrubby communities in the Venezuelan Gran Sabana Plateau

Hokche, Omaira, Ramírez, Nelson

2019

Overview

Abstract Breeding system, sexual system, temporal variation in sex expression and herkogamy were evaluated in seven herbaceous-shrubby communities from the Gran Sabana Plateau, Venezuela. This analysis was conducted considering the life form, substrate type, succulence, carbon metabolism, nutritional relation, successional stage, pollination system specificity and endemism of plant species. Of the 348 plant species studied, 73.8 % were hermaphrodite, 16.9 % were monoecious and 9.2 % were dioecious. Plant sexual systems such as dichogamy and herkogamy were associated with life form, nutritional relations, carbon metabolism and pollination systems. Most species were adichogamous, followed by protandrous and protogynous. Protandry was high for perennial herbs, annual herbs and trees, and protogyny was most frequent in perennial herbs. Protandrous and protogynous species were frequently anemophilous. Herkogamy was higher than non-herkogamy. Herkogamy was higher for trees, shrubs and liana; higher in monophilous and lower in anemophilous species. Most of the hermaphrodites were herkogamous and adichogamous species. In contrast, monoecy were commonly perennial herb and dichogamous species and frequently associated with anemophily. Dioecious species were trees and shrubs and with polyphilous pollination. Dioecy was the most frequent sexual system for endemic species. Hermaphrodite species were similarly distributed across plant communities. Monoecy was slightly higher for savanna and fallow than the other communities, and dioecy was higher for shrublands and secondary bushland. Most plant species were non-agamospermous, non-spontaneous self-pollinated and xenogamous. Partially self-incompatible dominated, followed by self-incompatible, partially cross-incompatible and the lowest frequency corresponded to cross-incompatible species. All these results are discussed in the context of evolutionary and ecological trends. Breeding system, sexual system, dichogamy and herkogamy taking place in seven herbaceous-shrubby communities from the Gran Sabana Plateau, Venezuela, showed diverse mating strategies associated with life forms, pollination system specificity, successional stage, endemism, vegetation structure and community isolation. High levels of outbreeding strategies such as dioecy, monoecy, non-agamospermy, non-spontaneous self-pollination, xenogamy and partial self-incompatibility occurred mainly in woody species from shrublands and secondary bushland. Inbreeding strategies, non-herkogamy, spontaneous self-pollination and partial cross-incompatibility are primarily associated with herbaceous life forms from disturbed communities. These reproductive attributes are discussed in the ecological and evolutionary context.

• Publisher: Oxford University Press
• Subject: Carbon / Endemic species / Endemism / Flowers & plants / Herbs / Hermaphrodites / Inbreeding / Metabolism / Outbreeding / Plant communities / Plant reproduction / Plant species / Pollination / Protandry / Shrubs / Studies / Temporal variability / Trees