Seed germination and seedling allogamy in Rosmarinus officinalis: the costs of inbreeding

García-Fayos, P, Castellanos, M C and Segarra-Moragues, J G (2018) Seed germination and seedling allogamy in Rosmarinus officinalis: the costs of inbreeding. Plant Biology. ISSN 1435-8603

[img] PDF - Accepted Version
Restricted to SRO admin only until 17 February 2019.

Download (774kB)


1) Self-pollination by geitonogamy is likely in self-compatible plants that simultaneously expose large numbers of flowers to pollinators. However, the progeny of these plants is often highly allogamous. Although mechanisms to increase cross-pollination have been identified and studied, their relative importance has rarely been addressed simultaneously in plant populations.
(2) We used Rosmarinus officinalis to explore the factors that influence the probability of self-fertilization due to geitonogamy or that purge its consequences, focusing on their effect on seed germination and allogamy rate. For doing this, we experimentally tested the effects of geitonogamy on the proportion of filled seeds and how it influences germination rates. Then during two field seasons, we studied how life-history and flowering traits of individuals influence seed germination and allogamy rates of their progeny in wild populations at the extremes of the altitudinal range. The traits considered were plant size, population density, duration of the flowering season, number of open flowers, flowering synchrony among individuals within populations, and the proportion of male-sterile flowers.
(3) We found that most seeds obtained experimentally from self-pollinations were apparently healthy but in fact empty, and that the presence of filled seeds drove the differences in germination rates between self- and cross-pollination experiments. Plants from wild populations consistently showed low germination rates and high rates of allogamy as determined with microsatellites. Germination rates related positively to the length of the flowering season, flowering synchrony and the rate of male-sterile flowers whereas the rate of allogamous seedlings was positively related only to the rate of male-sterile flowers.
(4) Rosemary plants purge most of the inbreeding caused by its pollination system by aborting seeds. This study showed that the rates of seed germination and of the resulting allogamy are a function of a complex combination of factors that vary in space and time. Male sterility of flowers, length of the flowering season and flowering synchrony of individuals within populations all favor high rates of cross-pollination, therefore increasing germination and allogamy rates. These flowering traits appear to be highly plastic and respond to local and seasonal environmental conditions.

Item Type: Article
Keywords: Reproductive biology, pollination, geitonogamy, male-sterile flowers, seed germination, allogamy
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Subjects: Q Science > QK Botany > QK0900 Plant ecology
Q Science > QK Botany > QK0900 Plant ecology > QK0926 Reproductive interrelation. Pollination
Depositing User: MariaClara Castellanos
Date Deposited: 26 Feb 2018 09:32
Last Modified: 26 Feb 2018 09:32

View download statistics for this item

📧 Request an update