Abstract Detail

Ecological Section

Teixido, Alberto L. [1].

Large flowers in stressful environments: the importance of floral longevity in a large-flowered Mediterranean family.

In entomophilous plants large flowers receive more pollinator visits and increase the fitness. However large flowers involve maintenance costs associated with water use. In dry and hot environments, large flowers may involve an elevated cost due to high transpiration rates. Floral longevity, considered a decisive character for plant reproductive success, may buffer the high costs of large flowers by means of a short flower lifespan. In this study, flowers of twelve species of Cistaceae, a large-flowered Mediterranean family, were monitored along a spatial gradient to relate flower size (cm) with floral longevity (days). An specific experiment on Cistus ladanifer, the largest-flowered species of the family, was carried out to know the floral longevity depending on pollen deposition (bagged vs. hand-pollination treatments) and temperature (six populations at two different altitudes). Flowers of Cistaceae showed a trend to last one day, independently of differences in flower size (range between 1.02±0.09 and 7.26±0.74 cm). Specific study of C. ladanifer reported that flower size was broadly variable along an altitudinal gradient (from 7.00±1.13 to 8.60±0.79 cm), and also within-populations and within-individuals, especially due to variability among flowering periods. A significant change in floral longevity was also recorded along the gradient, with a shift towards shorter-lived flowers (1.92±0.70 to 1.21±0.41 d). In addition, floral longevity reported a negative correlation with flower size, as well as an influence of pollen deposition and temperature. Bagged flowers tended to last longer (1.56±0.55 d) that control (1.25±0.36 d) and pollinated (1.04±0.11 d) flowers. On the other hand, high temperature (daily mean approx. 20ºC) had a differential effect since limited to one day the floral longevity independently of size and pollination of flowers. All these factors suggest that a short floral longevity could explain the appearance of large flowers in stressful environments and be an important factor on floral evolution in the Mediterranean area, maybe in relation to water use costs.

Broader Impacts:

1 - Universidad Rey Juan Carlos, Biodiversity and Conservation Area, Tulipan s/n, Móstoles, Madrid, 28933, Spain

Keywords:
floral longevity
flower size
Cistaceae
Mediterranean area
temperature
Maintenance costs.

Presentation Type: Oral Paper:Papers for Sections
Session: 33
Location: 555B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 11:00 AM
Number: 33004
Abstract ID:369