How Tank Bromeliads Respond to Changing Tank Conditions

Abstract

Bromeliads, particularly those with a water-holding tank formed by leaves, act as amplifiers of biodiversity in their tropical forest ecosystem. The tanks play host to a wide diversity of life forms, and provide the bromeliad with almost all of its water and mineral nutrients. Bacteria, insects, amphibians, and other plants thrive in the conditions created by the tank. To investigate the ecophysiological function of the bromeliad tank, studies were performed by changing tank conditions to see whether alterations would affect the plant and furthermore the bromeliad?s symbionts. Over the course of nine weeks, the effect of increased acidity, addition of nitrogen-rich plant detritus, and treatment with streptomycin on plant health and water absorption were tracked in three species. Tank pH, chlorophyll fluorescence, and stomatal conductance were measured to ascertain plant health. Analysis with one way RM ANOVA reports showed no significant difference in tank pH between detritus and streptomycin treated bromeliads, but a significant difference (P<0.001) was found in changes in water absorption in plants that had differing acidity levels. Extremely high acidity levels (pH 3 or lower) negatively affected the ability of the plant to successfully take up water. The plant, nevertheless, absorbed water at pH 4 (the optimal pH of a bromeliad tank). In other plants, water absorption is sharply reduced by a pH of 4, raising the question of whether bromeliads have anatomical or physiological specializations. Further studies on gene expression will be conducted through RNA analysis.