Resumo

GOMES, Filomena; SANTOS, Joana M.  e  CANHOTO, Jorge M.. Efeito de Vários Nutrientes no Crescimento in vitro de Raízes de Eucalyptus globulus. Silva Lus. [online]. 2003, vol.11, n.2, pp.153-163. ISSN 0870-6352.

Root growth and architecture of in vitro (in Petri dishes) growing seedlings of Eucalyptus globulus was studied in the presence of several nutrients (NH₄NO₃, KH₂PO₄ and KNO₃) and nutrient concentration (0.01; 0.1; 1; 10; 50 and 100 mM). In a first set of experiments seeds were germinated in the presence of the above-mentioned nutrients and the effect of several nutrient concentration determined. The following parameters were evaluated: 1) seed germination, 2) number of primary and lateral roots, 3) root length and 4) root biomass. In a second experiment Petri dishes were divided in three zones (top, middle, bottom) and the role of six salts (KNO₃, KCl, KH₂PO₄, NH₄NO₃, Ca(NO₃)₂ and CaCl₂) on the middle position was analysed. The parameters studied in this case were the number and length of lateral roots. The results showed that, for all salts, concentrations of 100 mM were inhibitory of seed germination. Best results for biomass and lateral root length were achieved when 1 mM KNO₃ was used. When primary root number was the factor analysed KH₂PO₄ gave the best results. In the second group of experiments it was found that the presence of 1 mM of KNO₃ at the middle position induced the best results concerning both lateral root number and root length. These preliminary results represent a first attempt to evaluate the role and interactions of several major nutrients on Eucalyptus globulus root growth and root architecture and can, in the future, give new insights about soil management and sustainability.

Palavras-chave : eucalypts; nutrients; root system; seedlings.

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