Silicon attenuates potassium and sulfur deficiency by increasing nutrient use efficiency in basil plants

The stress-mitigating effect promoted by silicon is well documented, but considering nutritional stress due to deficiency, which is common in plants, there is still a shortage of prominent research on vegetables, such as basil. Our objective was to verify the role of silicon (Si) in basil plants grown in hydroponics with complete nutrient solution and with the individual omission of N, K and S. The treatments were four nutrient solutions (complete nutrient solution (CS), without N, without K and without S) x two Si (absence and presence of 2 mmol L-1) x 4 replications in a completely randomized design. The evaluations performed were determination of the accumulation of Si, N, K and S, the use efficiency of N, K and S and the visual diagnosis of the deficiency of these nutrients. Under N deficiency, there was no effect of Si on N accumulation, N use efficiency or the dry mass of the plants. In plants deficient in K, Si improved K use efficiency and, consequently, shoot and root dry mass and mitigated the visual symptoms of K deficiency. With S deficiency, Si increased S accumulation, its use efficiency and consequently the shoot and root dry mass. In conclusion, these results indicate that Si did not mitigate the damage caused by severe N deficiency but that it did attenuate the damage caused by K and S deficiency by increasing the use efficiency of these nutrients.