This summary was contributed by Ashley Meyers.
“Hydrophobic leaf surfaces of Bromeliaceae possess a highly irregular microrelief, thereby reducing the adhesion and spread of water on the leaf blade. Hydrophobic trichome layers occur on the abaxial leaf blade surfaces of many mesic Type 1 pitcairnioids and, as these species exhibit the putative primitive ecological condition, water repellency appears to have been an important condition in early Bromeliaceae. The trichomes of Type 4 species are specialized for the alternative function of water and nutrient absorption from a water-filled tank, with epicuticular wax powders employed by some species to shed water from the leaf blades. Hydrophobic trichome layers and wax powders could potentially obstruct pathogens and particulates, aid in self-cleaning, and/or maintain gas exchange during wet weather.” (Pierce et al. 2001:1379)
“So successful are these techniques for sending seeds up into the canopy that the massive branches of many forest trees are often densely lined with squatters. These are known as epiphytes and among the commonest are bromeliads. They anchor themselves by wrapping their roots around the branch. Their long leaves grow in a tight rosette around their central bud and channel rain water down to it so that the rosette fills and forms a small pond.” (Attenborough 1995:166)
“Leaves with waxy trichomes are extremely water repellent… The crucial factor of superhydrophobicity in…leaves is given by the hairs, several hundreds of micrometres high, which are superimposed by a layer of small hydrophobic wax crystals… These surfaces are superhydrophobic, but the water droplets do not penetrate between the hairs; thus, small particles from the leaf surface would not be removed by rinsing with water… Such hairy systems may also be extremely useful for underwater systems because they minimize the wetted area of immersed surfaces and therefore may greatly reduce drag, as well as the rate of bio?lm formation, and are of great interest in biomimetics.” (Koch and Barthlott 2009:1496)
“…Although most studied functional changes were not directly associated with the transition from atmospheric to tank form, our results are consistent with the notion that the atmospheric stage is broadly associated with increased drought tolerance, whereas (larger) tanks allow improved access to nutrients.” (Zotz et al. 2004: 1350).