Anatomy and function of the root system of bromeliad Nidularium minutum

Abstract

The root anatomy of bromeliad Nidularium minutum Mez was studied and the efficiency of root system in contributing to the growth, development and mineral uptake of the species evaluated. To accomplish this analysis, four treatments were applied as follows: (i) control plants with 5 mL H2O on substrate and 5 mL H2O into tank; (ii) plants supplied with nutrients to the tank with 5 mL H2O on substrate and 5 mL Hoagland and Arnon solution into tank; (iii) plants supplied with nutrients to the roots with 5 mL HA on substrate and 5 mL H2O into tank; and (iv) plants supplied with nutrients to the tank and roots with 5 mL HA on substrate and 5 mL HA into tank. Biometric variables and biomass were measured. Contents of macro- and micronutrients were evaluated in leaves, and the anatomical structure of roots was analysed. Structurally, the roots possess multiseriate epidermis, termed velamen, which is typical in Orchidaceae and other families for taking up water and nutrients. Plants supplied with nutrients to the roots had higher values than control plants for fresh and dry mass of stems, leaves and total (leaves + stems + roots), besides being more efficient than plants supplied with nutrients to the tank for nitrogen uptake. These results indicate that root system of N. minutum is very efficient for nutrients uptake when compared with the tank contributing to plant growth and development, most likely assisted by the presence of velamen.