Survival, and anatomical and ecophysiological changes in isolated individuals of Tillandsia recurvata L. (Bromeliaceae) grown under different shading conditions

Abstract

Tillandsia recurvata L. may show morphophysiological plasticity in response to radiation availability, since this species is found in different environments. This work aimed to evaluate the anatomical and physiological modifications of T. recurvata isolated individuals under different shading levels and the consequences of these changes on the growth of this species. The individuals were exposed for 60 days to treatments as follows: full sun (unshaded) and shading of 35%, 75%, and 85%. Growth analyses were performed, and the leaf anatomy and water content were assessed. All plants submitted to full sun or 35% shading died, whereas those under 75% and 85% shading survived. The water content in leaves and rhizomes was higher under 85% shading, and this treatment increased the leaf area and the number of leaves in T. recurvata. Leaf dry mass, leaf elongation rate, biomass allocation to rhizomes, and net assimilation rate were higher under 85% shading. The leaves had a thicker hypodermis, lower proportions of both epidermis and vascular bundles, and a higher proportion of chlorophyll parenchyma under 85% shading. Tillandsia recurvata individuals behave as sciophytic, while the formation of clusters may change microclimate conditions; the behavior of clumped plants must be further investigated.