Effect of fertilisation with urea on development in the ornamental bromeliad Aechmea fasciata

Resumo

The aim of this study was to evaluate the effect of urea fertiliser on the bromeliad, Aechmea fasciata. Plants were submitted to weekly treatments with a solution of 0.0, 0.5, 1.0, 1.5 or 2.0 g urea L-1. After 210 days of the experiment, biometric variables of growth and development of the root and shoot systems were analysed, together with foliar levels of chlorophyll a and b, and of carotenoids. The experimental design was of randomised blocks with four replications; eight plants were used per plot. The data were submitted to regression analysis. The highest values for chlorophyll a and carotenoid content were obtained at a concentration of 1.23 g L-1 urea, and for chlorophyll b at a concentration 1.75 g L-1 urea. Plants of A. fasciata submitted to a solution with no nitrogen showed marked chlorosis of the leaves and reduced growth and development. The mean value for the maximum levels of photosynthetic pigments was 1.40 g L-1 urea, and this can be used as an indicator of the nutritional status of nitrogen in the species. From the results, an application of 1.46 g L-1 urea to the tank in A. fasciata is recommended, as this gave the greatest accumulation of total dry weight and an increase in the number of leaves.