Efeitos da aplicação foliar de selênio e potássio | Grupo Co. de sais inorgânicos de Yunnan, Ltd

Scientific Reports volume 12, Artigo número: 15119 (2022) Citar este artigo

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Neste estudo, os efeitos da aplicação foliar de selênio (Se) em diferentes concentrações foram examinados com base em mudanças em vários parâmetros, como concentração de nitrogênio, fósforo e potássio (NPK) no solo e na planta de aveia, rendimento de aveia, matéria orgânica no solo (OMS), antioxidantes não enzimáticos e teor total de fenol. As concentrações de cromo (Cr), ferro (Fe), manganês (Mn), zinco (Zn) e cobre (Cu) também foram avaliadas em palha e sementes de aveia. O estudo está em conformidade com as diretrizes locais e nacionais. A aplicação simultânea de humato de potássio (K-humato) com Se também foi investigada neste estudo. A aplicação de Se aumentou a biodisponibilidade de N e P no solo e sua concentração total na palha e nas sementes de cada planta. As concentrações de Se foram proporcionais à quantidade de fósforo encontrada no solo (solo P), mas não com as concentrações de K nas sementes (planta K). A aplicação de K-humato com Se aumentou a fração biodisponível do K-solo; no entanto, não aumentou a fração biodisponível da palha K ou da semente K. Embora a aplicação isolada de Se tenha aumentado substancialmente o rendimento, a aplicação simultânea de K-humato não mostrou efeito adicional. Além disso, as respostas de produtividade de sementes e comprimento de plantas não foram significativas após a aplicação de Se com ou sem K-humato. O OMS e o teor de fenol total foram proporcionais à taxa de aplicação de Se com e sem K-humato. O conteúdo de antioxidantes não enzimáticos também foi proporcional às concentrações de Se, mas não proporcional ao K-humato. As concentrações totais de Se no solo, na palha das plantas e nas sementes aumentaram com a adição de K-humato. Além disso, as concentrações totais de Cr foram reduzidas após a aplicação de Se e K-humato. A concentração de Fe na palha e nas sementes variou de um tratamento para outro, e a concentração de Mn foi reduzida em resposta à aplicação foliar de Se e K-humato. As concentrações de Zn na palha e nas sementes das plantas foram reduzidas com a aplicação de concentrações variadas de Se. O aumento da taxa de aplicação de Se induziu redução na concentração de Cu nas sementes. Em contrapartida, a aplicação simultânea de Se e K-humato aumentou a concentração de Cu nas sementes.

A investigação sobre o selénio (Se) começou quando Schwartz e Foltz descobriram que o Se nas forragens prevenia a cirrose hepática e a distrofia muscular em ratos1. Com base em suas propriedades antioxidantes e anticancerígenas, o Se possui diversas funções, como atuar como antioxidante em plantas2.

O crescimento das plantas não depende da concentração de Se disponível no solo. No entanto, as concentrações de Se na alimentação humana e animal têm implicações importantes para a saúde3. A fronteira entre as concentrações de Se que atendem aos requisitos nutricionais essenciais e as concentrações tóxicas de Se é estreita e é afetada pela forma química e pelas condições ambientais2. O Se pode modificar a capacidade das plantas de tolerar o estresse oxidativo induzido por UV, promover o crescimento de mudas envelhecidas e retardar a senescência. As nanopartículas de Se (SeNPs) afetaram o crescimento de cultivares de amendoim alterando os pigmentos fotossintéticos, os açúcares solúveis totais, as enzimas antioxidantes (peroxidase do ácido ascórbico, catalase e peroxidase), o teor de fenol, os flavonóides totais e a peroxidação lipídica. Em contraste, as condições do solo arenoso aumentaram a tolerância das plantas após a aplicação de SeNPs como estressor ou estimulante4. A aplicação de Se também reverteu o efeito negativo da salinidade na eficiência fotoquímica2. A aplicação de aditivo de Se reduziu a ocorrência de respostas adversas causadas por metais pesados, calor, ultravioleta(UV)-B, frio, estresse salino e seca5.

Os fertilizantes orgânicos, como o humato de potássio (KHM) e o ácido fúlvico de potássio (BSFA) são usados para prevenir doenças de plantas, melhorar a estrutura do solo e aumentar os níveis de nutrientes do solo6. A adição de KHM e BSFA remodelou as funções microbianas e os níveis de nutrientes aumentaram no solo de ginseng6. Além disso, a aplicação de KHM melhorou a germinação das sementes, a absorção de nutrientes e o crescimento das plântulas7.

Se2 > Se1 > control. Thus, Se was found to increase the available N-soil in an application-rate-dependent manner (Table 2). The availability of N-soil after Se application was improved via the simultaneous application of K-humate with the same rate-dependence as observed with Se alone. Comparable results were found using the sum of means for analysis. The insignificant difference found between the sum of means for control and treatment at an Se concentration of 12 × 10−3 mM Se may reflect the relatively low concentration of Se used./p> Se2 > Se1 > control (Table 3). Thus, the foliar application rate of Se caused a rate-dependent increase in the available P-soil. Simultaneous application of K-humate further increased P-soil availability. A rate dependency similar to Se alone was also observed with simultaneous Se and K-humate application. A similar result was observed using the sum of means for data analysis. Significant differences were observed among all treatments./p> Se2 > Se1 > control. Insignificant differences between values were observed when Se was applied without K-humate at concentrations of 12 × 10−3 and 63 × 10−3 mM, and for the sum of means for Se and K-humate applications at concentrations of 12 × 10−3 and 63 × 10−3 mM. Thus, the application rate of Se caused a proportional increase in P-soil, P-straw, and P-seeds. Furthermore, the simultaneous application of K-humate augmented this effect./p> Se2 > Se1 = control (Table 4). Again, the foliar application rate of Se causes a proportional increase, in this case, in K-soil. The application of K-humate with Se augmented this effect. A similar rate dependency was also observed with simultaneous application and when the sum of means was used. An insignificant difference was observed between the sum of means for controls and Se concentrations of 12 × 10−3 mM./p> Se2 > Se1 > control. The simultaneous application of K-humate increased the yield only slightly, resulting in insignificant differences. Similar findings were also observed when the sum of means was used. In contrast, seed production was not significantly affected, and plant length (m × 10–2) did not show a significant response. In contrast, Se application to potato plants enhanced tuber yield, plant growth, and quality compared with controls. Moreover, Se application along with different N additions ultimately increased potato productivity compared with Se or N alone23. Similarly, the grain yield increased when Se was applied; this application was significant at low levels24./p> Se2 > Se1 > control. The addition of K-humate by foliar application significantly augmented the OMS content (%) (Table 6). Application of Se also increased the non-enzymatic antioxidant content; however, the increases were insignificant at Se concentrations of 12 × 10−3 and 63 × 10−3 mM. The highest values for non-enzymatic antioxidants were observed at Se concentrations of 88 × 10−3 mM. The application of K-humate along with Se did not significantly augment the effects observed after the application of Se alone. Analyses using the sum of means were completely consistent with these findings./p> Se2 > Se1 > control. Furthermore, this effect was significantly amplified with the simultaneous application of K-humate. Analysis using the sum of means gave comparable results. Se enhances the ability of plants to cope with stress by stimulating plant cell antioxidant capacity though the upregulating of antioxidant enzymes, such as CAT, SOD, and GSH-Px. Se also increases the synthesis of PCs, GSH, proline, ascorbate, alkaloids, flavonoids, and carotenoids. Se may also induce the spontaneous dismutation of the superoxide radical into H2O2. Elevated antioxidant capacity can reduce lipid peroxidation by lowering ROS accumulation under metal-induced oxidative stress conditions25. Application of Se using foliar spray also induced an increase in the concentration of rosmarinic acid20./p> Se2 > Se1 > control. The additional application of K-humate significantly amplified these effects (Table 7). The treatment of K-humate that increased Se content in the soil may be owing to experimental errors, however, increasing Se content in either straw or seeds may be owing to the increased stimulating movement from soil to different parts of the plant. Se-straw content increased with increasing the Se foliar application; this effect decreased in the following order: Se3 > Se2 > Se1 > control. The simultaneous application of K-humate augmented the effects observed after the application of Se alone. Total Se concentration also increased Se-seeds like Se-straw for Se alone, Se with K-humate, and using the sum of means for analysis./p> Se3 > Se1. In response to Se application, the Cr-straw content decreased (Table 8). The difference between Se2 and Se3 was insignificant. K-humate addition induced a notable increase in Cr-straw in the following order: control > Se3 > Se2 > Se1. This may be owing to the increased stimulating movement of Cr from soil to different parts of the plant. Results obtained from Se treatments varied depending on the presence of K-humate. Cr-seeds decreased in the following order: Se2 > Se3 > Se2 > control. The addition of K-humate increased the Cr-seed content compared with Se alone; however, the difference between Se2 and Se3 was insignificant. Analysis using the sum of means did not produce significant differences./p> Se1 > control > Se2 (Table 9). Differences were insignificant among control, Se1, and Se2. K-humate caused concentrations of Fe-straw to significantly increase in the following order: control > Se3 > Se2 > Se1. Differences between control and Se3 as well as Se1 and Se2 were insignificant. Analysis using the sum of means was similar. Neither Se nor Se with K-humate applications produced significant changes in Fe-seeds. Analysis using the sum of means was similar. Low concentration of Se application may enhance plant productivity and encourage phytoremediation by improving plant tolerance to stress and enhancing photosynthesis25. Further, a significant increase was observed in concentrations of Fe and S in rice grain grown in N-limiting conditions while Ca that have been treated with Se regardless of N supply21./p> Se2 > Se1 > Se3. No significant difference was found between control and Se1 (Table 10). In contrast, K-humate addition further reduced Mn-straw concentrations in the following order: control > Se1 > Se3 > Se2. The control and Se1 were not significantly different when using the sum of means for analysis. Likewise, no significant difference was seen between Se1 and Se3. Accumulation of Mn in seeds varied among treatments in the following order: control > Se2 > Se3 > Se1. K-humate addition altered this order to be in the following order: control > Se2 > Se1 > Se3. No significant differences were observed between Se2 and Se3 when the sum of means for analysis was used. Previously, the application of Se increased the concentrations of Mg and molybdenum in grains grown in 16 and 24 mM N compared with N-limited plants21./p> Se1 > control > Se3 (Table 11). The application of K-humate with Se resulted in some insignificant variations compared with the application of Se alone. Control, Se1, and Se3 were insignificantly different when the sum of means was used for the analysis. Concentrations of Zn in seeds were reduced after Se application. K-humate with Se foliar application altered the concentration of Zn in seeds with impacts in the following order: control > Se3 > Se1 > Se2. The difference between Se1 and Se3 was insignificant. Additionally, insignificant differences in Zn concentrations after application of Se1, Se2, and Se3 were found when the sum of means was used for analysis. Low concentrations of Se possibly enhance plant productivity and phytoremediation capacity by improving the ability of plants to tolerate stress and enhancing photosynthesis25./p> control > Se2 > Se3 as it shown in Table 12. Application of Se with K-humate showed significant changes in the Cu-straw content in the following order: Se1 > Se2 > control > Se3. No significant differences were observed using the sum of means for analyses. In contrast, the foliar application of Se resulted in increases in Cu-seed at concentrations of Se1 and Se3; however, at 63 × 10−3 mM (Se2), a reduction in Cu-seed was observed. K-humate with Se simultaneously resulted in increased Cu-seed content with impacts decreasing in the following order: Se3 > Se1 > control > Se2. The sum of means analysis showed no significant variation between control and Se2. Previously, the application of Se led to a decrease in the concentrations of Cu in grains grown in 16 and 24 mm N compared with N-limited plants21./p> Se1 > control > Se3. Concentrations of Zn in oat seeds were reduced by Se supplementation. Increases in Se concentrations from 12 × 10−3 to 88 × 10−3 mM reduced Cu-seed, and Se application with K-humate produced only insignificant increases in the Cu-straw content in the following order: Se1 > Se2 > control > Se3. The additional application of K-humate altered this order to Se3 > Se1 > control > Se2./p>