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This study is aimed at assessing whether silicon (Si) can mitigate the effects caused by water stress in pre-sprouted seedlings (PSS) in sugarcane after their transplanting in the soil and what is the best form in the application if via nutrient solution or leaf spraying. The treatments were arranged in a 3 × 3 factorial scheme with silicon supply via nutrient solution (2 mmol L−1), Si via leaf application (3.4 mmol L−1), and without Si (control) and three levels of soil water retention capacity (70%, 50%, and 30%), for 30 days. In the absence of Si, the water deficit was damaging to the physiological, growth, and dry matter production variables of plants, in a 30% level of soil water retention capacity. Silicon supply via nutrient solution was more efficient when compared with Si via leaf spraying in the formation of pre-sprouted sugarcane seedlings in the first 30 days after transplanting, since it increased the quantum efficiency of photosystem II, chlorophyll content, leaf water potential, and water content, decreased cell electrolyte leakage and free proline content, and allowed a higher growth and biomass production. In conclusion, the supply of Si via nutrient solution in pre-sprouted sugarcane seedlings can be considered a feasible alternative to alleviate water deficit damage imposed after transplanting, in a 30% level of soil water retention capacity.

The objective of this study was to evaluate the effect of silicon (Si) on iron (Fe) deficiency in sorghum plants grown in a nutrient solution, seeing that sorghum crops are sensitive to iron deficiency and Si may alleviate this deficiency. Nonetheless, the nutritional mechanisms underlying this process have not been fully elucidated in this plant species. Treatments were arranged in a 2 × 2 factorial scheme and completely randomized block design, in the absence or presence of Si (2 mmol L−1) and under Fe deficiency or sufficiency, with five repetitions. The sources of Si and Fe were stabilized sorbitol sodium and potassium silicate (Si = 113.4 g L−1) and Fe-EDDHA chelate (Fe = 6%), respectively. The plants were cultured in pots filled with washed sand, and Si was supplied via nutrient solution at a concentration of 2 mmol L−1. The concentrations of Fe used in this study were 368 μmol L−1for sufficiency conditions and 55.2 μmol L−1for deficiency conditions. Our results showed that Si has a beneficial effect on sorghum plants under Fe deficiency by increasing the chlorophyll content and decreasing concentration of malondialdehyde (MDA). In addition, the application of Si increased the efficiency of translocation and utilization of Fe in plants under this micronutrient deficiency. In conclusion, Si reduced Fe deficiency in sorghum plants by increasing the concentration of photosynthetic pigments, reducing lipid peroxidation, improving the efficiency of Fe translocation and utilization, and resulting in a greater dry weight accumulation.