Silício atenua os efeitos tóxicos do alumínio em plantas jovens de cana-de-açúcar cultivadas em hidroponia

• Autor(a) principal: Sousa Junior, Gilmar da Silveira [UNESP]
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/150265
• topic: Saccharum spp.; Estresse ácido; Osmólitos compatíveis; Estresse oxidativo; Pigmentos; Anatomia radicular

Aiming to evaluate if Silicon (Si) ameliorates Aluminum (Al) toxicity in young sugarcane plants, at this work were assessed physiological parameters of biomass accumulation, lipid peroxidation through evaluation of hydrogen peroxide (H2O2) and malondialdehyde (MDA), contents of the non-enzymatic compounds proline (Pro) and glycine betaine (GB), and chlorophyll pigments (chl a and b). Furthermore, to determine if there was Si attenuated deleterious effects caused by Al, an anatomical study of roots was carried out. The experimental design was a 2x4x4 layout, with two sugarcane cultivars (CTC9002 and CTC9003), four Al sulfate concentrations (0.0; 10.0; 15.0; and 20.0 mg L-1) and two potassium silicate concentrations, absence (0.0 mg L-1) and presence (2.0 mmol L-1). There were three replicates in triplicate for each evaluation, except for growth. For obtaining young plants, micro seed pieces were sown and grown in sterilized sand for 30 days. After this period, the plants were acclimated in nutrient solution for 30 days. Then, the plants were submitted to the Al treatments, and grown in hydroponics for 15 days. Only then Si treatments were applied, with plants growing under Al toxicity and in the presence or absence of Si for additional 20 days. All the biological evaluations were performed 35 days after the plants were exposed to Al and Si treatments. Comparing the results obtained from young plants under Al toxicity and without Si, it was verified that Si supply improved growth, what can be attributed to a decrease in lipid peroxidation verified through lower H2O2 and MDA rates, to higher accumulation of proline and lower decrease in chlorophyll a and b contents, besides the mitigation of deleterious effects caused by Al in roots. Unlike Pro results, GB contents were reduced by Si in plants under Al stress, not having antioxidant activity through Si addition. It is concluded that Si presence ameliorated Al stress in both sugarcane cultivars, with higher protection to cv. CTC9003, which demonstrated lower sensitivity to toxicity when compared to cv. CTC9002.