Nitrogen efficiency indexes for evaluating nitrogen uptake and use in ornamental bromeliad’s root system and tank

Karina Gonçalves Da Silva,Plínio Barbosa De Camargo,Mauricio Lamano Ferreira,Emerson Alves Da Silva,Armando Reis Tavares,Shoey Kanashiro

doi:10.1590/s0100-204x2018000600006

Karina Gonçalves Da Silva, Plínio Barbosa De Camargo + Show 4 more

Open Access

https://doi.org/10.1590/s0100-204x2018000600006

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Abstract

Abstract: The objective of this work was to evaluate if nitrogen use efficiency (NUE) indexes can elucidate functional differences in nutrient uptake between the root system and tank of epiphytic bromeliads. The bromeliads Guzmania lingulata and Vriesea 'Harmony' received fertilizers in their tanks or through their roots using modified Hoagland & Arnon solution, with 0.00, 2.62, or 5.34 mmol L-1 nitrogen, as urea. After 90 days, nitrogen contents in leaves and plant biomass were evaluated, and NUE indexes were calculated. Guzmania lingulata and V. 'Harmony' fertilized in their tanks with 5.34 mmol L-1 had the highest averages of nitrogen uptake efficiency and recovery efficiency; those fertilized with 2.62 mmol L-1 through their roots showed the highest averages of NUE, nitrogen utilization efficiency, nitrogen physiological efficiency, and biomass conversion efficiency. The NUE indexes, besides being an effective tool to assess the nutritional status of ornamental bromeliads, reveal that the root system of epiphytic bromeliads is functional for nitrogen uptake and use.

Highlights

The morphological and physiological diversity found in bromeliad species allows this plant group to occupy a wide range of habitats
Other anatomical studies on the roots of bromeliads have shown the presence of velamen, which is an important structure associated with water and nutrient uptake through a passive movement in the roots; this structure is present in several taxa of epiphytic monocotyledonous families, such as Orchidaceae, Bromeliaceae, and Araceae, representing an example of convergent evolution (Silva & Scatena, 2011; Dettke & MilanezeGutierre, 2008; Males, 2016)
The objective of this work was to evaluate if nitrogen use efficiency (NUE) indexes can elucidate functional differences in nutrient uptake between the root system and tank of epiphytic bromeliads

Summary

Introduction

The morphological and physiological diversity found in bromeliad species allows this plant group to occupy a wide range of habitats. These varying characteristics and growth habits determine the uptake and utilization of nutrients by these plants, which have adapted to the low and intermittent nutrient supply available in the epiphytic habitat (Lüttge, 2010; Gonçalves et al, 2016). Other anatomical studies on the roots of bromeliads have shown the presence of velamen, which is an important structure associated with water and nutrient uptake through a passive movement in the roots; this structure is present in several taxa of epiphytic monocotyledonous families, such as Orchidaceae, Bromeliaceae, and Araceae, representing an example of convergent evolution (Silva & Scatena, 2011; Dettke & MilanezeGutierre, 2008; Males, 2016). The observed functional division between roots (plant anchorage) and tank (nutrient and water uptake) explains the different cultivation systems adopted for bromeliads

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