Silício e Selênio in vitro: impactos na aclimatização e morfofisiologia de plantas de batata-doce

Abstract

Sweet potato (Ipomoea batatas (L.) Lam.) is a very important food source for the global population's food security, primarily due to its hardiness and relatively simple cultivation. Among its propagation methods, tissue culture stands out, which, in addition to providing plant pathogen-free seedlings, allows for changes in the culture medium and specific movements. The objective of this study was to evaluate the effects on the acclimatization and development of sweet potato cv. Campina plants, from seedlings supplemented with silicon and selenium in vitro. The explants were inoculated into Murashige & Skoog (MS) culture medium, added with 30g L-1 of sucrose, and solidified with 6g L-1 of agar, with a pH adjusted to 5.8. The explants were treated with the following concentrations: T1- control (MS without silicon and/or selenium supplementation), T2- 10.405 µmol L⁻¹ of silicic acid (H₄SiO₄) (Si), T3- 10.405 µmol L⁻¹ of Si + 15 µmol L⁻¹ of sodium selenite. (Na₂SeO₃) (Se), T4- 10.405 µmol L⁻¹ Si + 20 µmol L⁻¹ Se, T5- 10.405 µmol L⁻¹ Si + 25 µmol L⁻¹ Se and T6- 10.405 µmol L⁻¹ Si + 30 µmol L⁻¹ Se. The plants were removed from the flasks after 60 days of inoculation and washed in running water to remove the culture medium residues adhered to the roots, transplanted into containers filled with substrate and acclimatized in a greenhouse. The experimental design was randomized, containing 5 replicates per treatment, totaling 30 experimental plots. Biometric parameters were evaluated at 7, 30, and 70 days after transplantation (DAT). Photosynthetic pigments were evaluated at 60 days, ultrastructural traits were evaluated at 70 days, and biomass accumulation was evaluated at 180 days. At 7 days, there was a statistically significant difference in shoot length for treatments T1 and T2, with superior performance (averages of 18.50 cm and 14.38 cm, respectively). The treatment with a concentration of 30 µmol L⁻¹ Se, combined with silicon, resulted in the best chlorophyll and carotenoid indices, in addition to greater root biomass. Scanning electron microscopy (SEM) micrographs revealed gradual variations in stomatal morphology, especially in ostiole opening and cuticular margin definition. The combined application of silicon and selenium proved effective in improving seedling quality during acclimatization and in the development of sweet potato cv. Campina plants in a greenhouse.