Silicon via fertigation with and without potassium application, improve physiological aspects of common beans cultivated under three water regimes in field.

Frequent droughts have led to an expansion of irrigated common bean (Phaseolus vulgaris L.) cultivation areas. An effective strategy to enhance water use efficiency and optimize crop growth is the application of silicon (Si) and potassium (K). However, the interaction between Si dosage, water regimes, and plant potassium status, as well as the underlying physiological mechanisms, remains unknown. This study aimed to assess the effects of Si doses applied via fertigation under various water regimes, in the presence and absence of potassium fertilization, on gas exchange, water use efficiency, and growth of Common beans in field conditions. Two experiments were conducted, one with and one without K supply, considering that the potassium content in the soil was 6.4 mmolc dm-3 in both experiments and a replacement dose of 50 kg ha was applied in the with K treatment, with the same treatments evaluated in both potassium conditions. The treatments comprised a 3 × 4 factorial design, encompassing three water regimes: 80% (no deficit), 60% (moderate water deficit), and 40% (severe water deficit) of soil water retention capacity, and four doses of Si supplied via fertigation: 0, 4, 8, and 12 kg ha-1. Where it was evaluated, content of photosynthetic pigments, fluorescence of photosynthesis, relative water content, leaf water potential and electrolyte extravasation, dry mass of leaves, stems and total. The optimal doses of Si for fertigation application, leading to increased Si absorption in plants, varied with decreasing soil water content. The respective values were 6.6, 7.0, and 7.1 kg ha-1 for the water regimes without deficit, with moderate water deficit, and with severe water deficit. Fertigation application of Si improved plant performance, particularly under severe water deficit, regardless of potassium status. This improvement was evident in relative water content, leaf water potential, and membrane resistance, directly impacting pigment content and gas exchange rates. The physiological effects resulted in enhanced photosynthesis in water-deficient plants, mitigating dry mass production losses. This research demonstrates, for the first time in common bean, the potential of Si to enhance irrigation efficiency in areas limited by low precipitation and water scarcity.

Silicon in the form of nanosilica mitigates P toxicity in scarlet eggplant.

Intensive fertilization of vegetables can promote phosphorus (P) toxicity. However, it can be reversed using silicon (Si), although there is a lack of research clarifying its mechanisms of action. This research aims to study the damage caused by P toxicity to scarlet eggplant plants and whether Si can mitigate this toxicity. We evaluated the nutritional and physiological aspects of plants. Treatments were arranged in a 2 × 2 factorial design of two nutritional levels of adequate P (2 mmol L-1 of P) and toxic/excess P (8 to 13 mmol L-1 of P) combined with the absence or presence of nanosilica (2 mmol L-1 Si) in a nutrient solution. There were six replications. The excess P in the nutrient solution caused damage to scarlet eggplant growth due to nutritional losses and oxidative stress. We found that P toxicity can be mitigated by supplying Si, which decreases P uptake by 13%, improves C:N homeostasis, and increases iron (Fe), copper (Cu), and zinc (Zn) use efficiency by 21%, 10%, and 12%, respectively. At the same time, it decreases oxidative stress and electrolyte leakage by 18% and increases antioxidant compounds (phenols and ascorbic acid by 13% and 50%, respectively), and decreases photosynthetic efficiency and plant growth by 12% (by increasing 23% and 25% of shoot and root dry mass, respectively). These findings allow us to explain the different Si mechanisms used to reverse the damage caused by P toxicity to plants.

Impact of Nanotechnology from Nanosilica to Mitigate N and P Deficiencies Favoring the Sustainable Cultivation of Sugar Beet.

This research aimed to study the effects of the nanosilica supply on Si absorption and the physiological and nutritional aspects of beet plants with N and P deficiencies cultivated in a nutrient solution. Two experiments were performed with treatments arranged in a 2 × 2 factorial scheme in randomized blocks with five replications. The first experiment was carried out on plants under a N deficiency and complete (complete solution with all nutrients), combined with the absence of Si (0 mmol L-1) and the presence of Si (2.0 mmol L-1). In the other experiment, the plants were cultivated in a nutrient solution with a P deficiency and complete, combined with the absence (0 mmol L-1) and the presence of Si (2.0 mmol L-1). The beet crop was sensitive to the N and P deficiencies because they sustained important physiological damage. However, using nanosilica via fertigation could reverse the damage. Using nanotechnology from nanosilica constituted a sustainable strategy to mitigate the damage due to a deficiency in the beet crop of the two most limiting nutrients by optimizing the physiological processes, nutritional efficiency, and growth of the plants without environmental risks. The future perspective is the feasibility of nanotechnology for food security.