Plastic Responses Contribute to Explaining Altitudinal and Temporal Variation in Potential Flower Longevity in High Andean Rhodolirion montanum

• Published in: PLOS ONE
• Main Authors: Pacheco Sandoval, Diego Andrés, Dudley, Leah, Cabezas Alvarez, Josefina, Cavieres, Lohengrin, Arroyo, Mary T. K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library Science 2016
• Subjects: Campanula-rotundifolia campanulaceae; Central Chilean Andes; Floral longevity; Pollen limitation; Pollinator visitation; MT-olympos; Reproductive success; Polemonium-viscosum; Individual flowers; Size variation; Campanula rotundifolia
• Online Access: https://doi.org/10.1371/journal.pone.0166350; https://repositorio.uchile.cl/handle/2250/145912

The tendency for flower longevity to increase with altitude is believed by many alpine ecologists to play an important role in compensating for low pollination rates at high altitudes due to cold and variable weather conditions. However, current studies documenting an altitudinal increase in flower longevity in the alpine habitat derive principally from studies on open pollinated flowers where lower pollinator visitation rates at higher altitudes will tend to lead to flower senescence later in the life-span of a flower in comparison with lower altitudes, and thus could confound the real altitudinal pattern in a species' potential flower longevity. In a two-year study we tested the hypothesis that a plastic effect of temperature on flower longevity could contribute to an altitudinal increase in potential flower longevity measured in pollinator-excluded flowers in high Andean Rhodolirium montanum Phil. (Amaryllidaceae). Using supplemental warming we investigated whether temperature around flowers plastically affects potential flower longevity. We determined tightly temperature-controlled potential flower longevity and flower height for natural populations on three alpine sites spread over an altitudinal transect from 2350 and 3075 m a.s.l. An experimental increase of 3.1 degrees C around flowers significantly decreased flower longevity indicating a plastic response of flowers to temperature. Flower height in natural populations decreased significantly with altitude. Although temperature negatively affects flower longevity under experimental conditions, we found no evidence that temperature around flowers explains site variation in flower longevity over the altitudinal gradient. In a wetter year, despite a 3.5 degrees C temperature difference around flowers at the extremes of the altitudinal range, flower longevity showed no increase with altitude. However, in a drier year, flower longevity increased significantly with altitude. The emerging picture suggests an increase in flower longevity along the altitudinal ...