Silicon in cacao plants exposed to UV-B radiation

• Autor(a) principal: Zanetti, Leonardo Valandro
• Data de Publicação: 2023
• Outros Autores: Werner, Elias Terra, Cuzzuol, Geraldo Rogério Faustini, Milanez, Camilla Rozindo Dias
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/27437
• topic: oxidative stress; photosynthesis; plant anatomy; plant growth; ultraviolet radiation; estresse oxidativo; fotossíntese; anatomia vegetal; crescimento vegetal; radiação ultravioleta

The objective of this work was to evaluate silicon capacity to mitigate the damaging effects of UV-B radiation on cacao (Theobroma cacao) plants. For the experiment, homogeneous cacao plants produced from seeds collected from a clonal population were subjected to the following treatments: UVB- Si-, no UV-B exposure and no addition of Si (control); UV-B+ Si-, UV-B exposure of 3.0 kJ m-2 per day and no addition of Si; and UV-B+ Si+, UV-B exposure of 3.0 kJ m-2 per day and addition of 2.0 mmol L-1 Si. The molybdenum blue technique was used to determine Si concentrations. For each selected plant, the following were determined: number of leaves; leaf area; root, stem, and leaf dry mass; anatomy of fully expanded leaves; gas exchange; chlorophyll a fluorescence; total soluble sugar concentrations using ethanol extract; and antioxidant enzyme activity. The plants showed a higher leaf and total biomass when treated with Si, as well as lower concentrations of chlorophyll, carotenoids, anthocyanins, flavonoids, and polyphenols under UV-B radiation. Si inhibits the net CO2 assimilation rate and the dark mitochondrial respiration rate. Therefore, Si application on cacao plants mitigates the damaging effects of UV-B, reduces carbon consumption through cellular respiration, and decreases the production of UV-B-absorbing compounds.