Göttlinger & Lohaus (Article) Abiotic factors, Epiphyte

Influence of light, dark, temperature, and drought on metabolite and ion composition in nectar and nectaries of an epiphytic bromeliad species (Aechmea fasciata)

Author(s):—T. Göttlinger & G. Lohaus

Publication:—Plant Biology n/a(n/a): -. — DOI

Abstract:—Summary Research into the influence of stress factors such as drought, different temperatures, and or varied light conditions on plants due to climate changes is becoming increasingly important. Epiphytes, like many species of the Bromeliaceae, are particularly affected by this, but little is known about impacts on nectar composition and nectary metabolism. We investigated the influence of drought, different temperatures and light-dark regimes on nectar and nectaries of the epiphytic bromeliad species, Aechmea fasciata, and the influence of drought also with the terrestrial bromeliad, Billbergia nutans. The contents of sugars, amino acids, and ions in nectar and nectaries were analyzed using HPLC. In addition, the starch content and the activities of different invertases in nectaries were determined. Compositions of nectar and nectaries were hardly influenced, neither by light or dark nor by different temperatures. In contrast to this, drought revealed changes in nectar volumes and nectar sugar compositions in the epiphytic bromeliad as well as in the terrestrial bromeliad. In both species, the sucrose-to-hexoses ratio in nectar decreased considerably during the drought period. These changes in the nectar sugar composition do not correlate with changes in the nectaries. The total sugar, amino acid, and ion concentrations remained constant in nectar as well as in nectaries during the drought period. Changes in nectar composition or in the production of floral pollinator rewards are likely to affect plant-pollinator interactions. It remains questionable in how far the adaptations of the bromeliads to drought and diverse light or temperature conditions are still sufficient.

Keywords:—amino acids, Bromeliaceae, drought, floral nectar, nectar composition, nectary composition, sugars