Estudo morfofisiologico do desenvolvimento das especies Galianthe grandifolia E. L. Cabral (Rubiaceae) e Campulocliniun chlorolepis Baker (Asteraceae) submetidas a diferentes concentrações de cadmio / Morphophysiological development of Galianthe grandifolia E. L. Cabral (Rubiaceae) and Campulocliniun chlorolepis Baker (Asteraceae) subjected to different cadmium concentrations

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The accumulation of toxic metals in the soil brings forth great environmental damages, especially cadmium, due to its high toxicity and cumulative effects on the organisms in general. There are a few studies regarding heavy metals and Cerrado native species. The aim of this work was to assess the behavior of two Cerrado species cultivated in the greenhouse: Campuloclinium chlorolepis (Asteraceae) and Galianthe grandifolia (Rubiaceae), as affected by cadmium (Cd) excess in the soil. Both species were watered with aqueous solutions of 0, 0.3, and 3 mmol L-1 of Cd. The results showed that the species have different tolerance levels to the Cadmium concentrations to which they were submitted. Campuloclinium chlorolepis resisted during fourteen days, subjected to the concentrations of 0.3 and 3 mmol L-1 of Cadmium and, at these same concentrations, Galianthe grandifolia remained alive up to 28 days. The main symptoms of Cd fitotoxicity were: clorosis, stained and withered leaves and growth inhibition in Campuloclinium chlorolepis; epinasty and stained leaves in Galianthe grandifolia. There was no growth inhibition in Galianthe grandifolia, but rather growth stimulation, even in the highest concentration (3 mmol L-1 of Cd). The Cd content analysis revealed that Galianthe grandifolia is more tolerant and a hyperaccumulator of this metal, with a mean accumulation of 120.37 mg Kg-1 in the tissues of shoots, and 298.97 mg Kg-1 of Cd in the underground system. Campuloclinium chlorolepis showed greater concentrations of Cd in the shoots (22.07 mg Kg-1) rather than in the roots (7.97 mg Kg-1). In this work, peculiarities of both species were also analyzed. Globular inulin-type fructans were detected in all tissues of the tuberous roots of Campuloclinium chlorolepis, except for the epidermis. In the underground system of Galianthe grandifolia, the shoot buds sprouting from the xylopodium are protected by colleters. In addition, the two species showed an association with both arbuscular mycorrhizal fungi and dark septate endophytic fungi, which co-occur in the tuberous and the thin roots of Campuloclinium chlorolepis, but colonize only the adventitious roots of Galianthe grandifolia.

ASSUNTO(S)

micorriza plant anatomy cadmio anatomia vegetal mycorrhizas fructans brazil flora dos cerrados - brasil frutanos cadmium cerrado flora

ACESSO AO ARTIGO

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