On-line version ISSN 1678-992X
LIMA FILHO, O. F. de and MALAVOLTA, E. SINTOMAS DE DESORDENS NUTRICIONAIS EM ESTÉVIA Stevia rebaudiana (Bert.) Bertoni. Sci. agric. [online]. 1997, vol.54, n.1-2, pp. 53-61. ISSN 1678-992X. http://dx.doi.org/10.1590/S0103-90161997000100008.
Symptoms of the deficiencies of N, P, K, Ca, Mg and B, as well as the toxicity symptoms of B and Zn in stevia plants, growing in nutrient solution, are described. -N: reduced development, small leaves, few branches and generalized yellowing. -P: reduced growth. -K: leaves curving downward, seeming to have lower water content, yellowing and necrosis of older leaves and smaller stem plus branches proportion. -Ca: dark spots, chlorosis and necrosis in leaves as well as wilting and collapse at the upper portion of stem. -Mg: interveinal paling in some older leaves, with an inverted V appearance. -B: roots with growth reduced, thickening, short ramification and general darkening; chlorosis followed by necrosis and deformation of leaves; young leaves with symptoms had smaller chlorophyll content; stem and branches showed crackings with reddish coloration, like salient veins of the leaves; plants had fewer branches. Plants with B toxicity showed brown spots at margins and tips of older leaves, followed by necrosis. Plants with Zn toxicity had necrotic spots, first in older leaves, with irregular size and shape, followed by wilting and death of the plant.
Keywords : stevia; mineral; nutrition; deficiency; toxicity; symptoms.