Floral allocation at different altitudes in highly autogamous alpine Chaetanthera euphrasioides (Asteraceae) in the cent
- PDF / 337,822 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 5 Downloads / 172 Views
ORIGINAL PAPER
Floral allocation at different altitudes in highly autogamous alpine Chaetanthera euphrasioides (Asteraceae) in the central Chilean Andes Mary T. K. Arroyo • Diego A. Pacheco Paulina Aguilera
•
Received: 30 July 2012 / Accepted: 20 November 2012 / Published online: 9 December 2012 Ó Swiss Botanical Society 2012
Abstract In the alpine life-zone, increasingly slower and unpredictable pollination at the higher altitudes predict an increase in floral investment in strongly outcrossing, pollenlimited biotically pollinated plant species, but not in autonomously self-pollinating species. Plant size, floral and above-ground vegetative biomass and individual capitulum biomass were studied in highly autogamous Chaetanthera euphrasioides (DC.) F. Meigen (Asteraceae) at 2,400 m a.s.l. and 3,300–3,400 m a.s.l. in the high Andes of central Chile. Contrary to prediction, altitude had a small positive effect on floral biomass investment and the anisometric relationship between floral investment, and plant size differed at the two altitudes. Individual capitulum size, however, was not affected by altitude. Plastic floral allocation and selection to increase seed production and ameliorate stronger inbreeding at the higher elevations are discussed as possible explanations for the small but unexpected altitudinal increase in floral allocation. Keywords Alpine Andes Autonomous self-pollination Chaetanthera euphrasioides Floral investment
M. T. K. Arroyo (&) D. A. Pacheco Institute of Ecology and Biodiversity (IEB) and Departamento de Ciencias Ecolo´gicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile e-mail: [email protected] P. Aguilera Departamento de Biologı´a, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile
Introduction In the harsh alpine habitat, all stages of sexual reproduction are constrained by low temperatures and depend on the availability and timely mobilization of adequate resources from the vegetative plant body to reproductive structures. Pollination is the first of the sequence of events leading to seed production and, hence, is of fundamental importance for the success of all later reproductive stages. Flower visitation rates have been found to decline with elevation at the community level (Arroyo et al. 1985; Arroyo and Squeo 1990), among species of the same genus (Blionis and Vokou 2001) and among populations of the same species (Bingham and Orthner 1998; Utelli and Roy 2000). Although lower pollination rates may be compensated by longer flower lifespans (Arroyo et al. 1985; Primack 1985; Stensto¨m and Molau 1992; Kudo and Molau 1999; Bingham and Orthner 1998; Utelli and Roy 2000; Arroyo et al. 2006; Steinacher and Wagner 2010; Torres-Dı´az et al. 2011), pollen limitation occurs in many arctic and alpine species (Garcı´a-Camacho and Totland 2009; Torres-Dı´az et al. 2011; Arroyo et al. 2012; Torres-Dı´az et al. 2011; Fulkerson et al. 2012). Differences in flower visitation rates across the altitudinal gradient predict altitudinal chang
Data Loading...
