Increased absorption and use of nutrients induced by Si is an indicator for tolerance to water deficit in a common bean cultivar cultivated in the field with and without application of K.

Introduction: Reduced water content in the soil triggers physiological, biochemical, and morphological damage to plants, aggravated by nutritional deficiency. One possible strategy to mitigate this damage comprises the use of silicon (Si). This study investigated whether Si can mitigate the damage caused by water deficit through nutritional mechanisms in bean plants grown under field conditions. Furthermore, it investigated whether the effectiveness of Si is influenced by water availability in the soil and the Si dose supplied. Methods: Therefore, two split-plot experiments were carried out: with and without K supply. In both experiments,the treatments comprised a 3 × 4 factorial scheme. Treatments included three water regimes: 80% (no water deficit), 60% (moderate water deficit), and 40% (severe water deficit) of the soil's water retention capacity. Moreover, they comprised four doses of Si supplied via fertigation-0 kg/ha, 4 kg/ha, 8 kg/ha, and 12 kg/ha-arranged in a randomized block design with four replications. Results and discussion: The appropriate dose of Si to be applied increased with the severity of the water deficit, with the recommended dose being 6 kg/ha, 7 kg/ha, and 8 kg/ha of Si for adequate water conditions, moderate water deficit, and severe water deficit, respectively.

Nano-silicon and sodium mitigate damage by potassium deficiency in chicory.

Chicory is a food with high nutritional. The use of beneficial elements in plants, such as sodium (Na) and silicon (Si), may be important to mitigate nutritional disorders, such as potassium (K) deficiency, but research is lacking on this topic. The objective was to evaluate the effects of sodium and nano-silicon on the nutritional, physiological, growth, and quality parameters of chicory under K deficiency and sufficiency. We used a concentration for sufficient K (3.0 mmol L-1), K-deficiency (1.5 mmol L-1), combined with the lack or presence of Na (2.0 mmol L-1) and Si (2.0 mmol L-1). The experiment was carried out in a greenhouse with six treatments corresponding to K sufficiency, K-sufficiency with Na, K-sufficiency with Si, K deficiency, K-deficiency with Na, and K-deficiency with Si, with six replications. The following growth variables were evaluated: (i) plant height, (ii) stem diameter, (iii) number of leaves, (iv) leaf area, and (v) plant biomass. Potassium and Si contents in the above ground part and K utilization efficiency were assessed, and the accumulation of K, Na, and Si was calculated. The efficiency of the quantum yield of photosystem II (Fv/Fm) and the photosynthetic pigments was determined. Electrolyte leakage index and relative water content, as well as phenolic compounds, ascorbic acid, and leaf firmness index were also determined. We found that supplying nano-Si and Na to a K-deficient nutrient solution increased K accumulation by 60% and 50% and K use efficiency by 79% and 62% compared to plants without supply of those elements. Nano-Si reduced electrolyte leakage, being 41% less than Na in K-deficient chicory. However, when Na was added to a nutrient solution with sufficient potassium, the K use efficiency decreased by 48% compared to sufficient potassium without Na. Under the same condition of sufficient supply of potassium and Na, K accumulation decreased by 20% in chicory compared to sufficient potassium without Na, and the photosynthetic pigments-total chlorophyll and carotenoids-were reduced by 5% and 10%, respectively. Our findings contribute to improve cultivation systems with low supply of K as the supply of Na and nano-Si mitigates the damage caused to the metabolism of chicory under K deficiency.

Silicon attenuates nutritional disorder of phosphorus in seedlings of Eucalyptus grandis × Eucalyptus urophylla.

BACKGROUND: Nutritional disorders of phosphorus (P), due to deficiency or toxicity, reduce the development of Eucalyptus spp. seedlings. Phosphorus deficiency often results in stunted growth and reduced vigor, while phosphorus toxicity can lead to nutrient imbalances and decreased physiological function. These sensitivities highlight the need for precise management of P levels in cultivation practices. The use of the beneficial element silicon (Si) has shown promising results under nutritional stress; nevertheless, comprehensive studies on its effects on Eucalyptus spp. seedlings are still emerging. To further elucidate the role of Si under varying P conditions, an experiment was conducted with clonal seedlings of a hybrid Eucalyptus spp. (Eucalyptus grandis × Eucalyptus urophylla, A207) in a soilless cultivation system. Seedlings were propagated using the minicutting method in vermiculite-filled tubes, followed by treatment with a nutrient solution at three P concentrations: a deficient dose (0.1 mM), an adequate dose (1.0 mM) and an excessive dose (10 mM), with and without the addition of Si (2mM). This study assessed P and Si concentration, nutritional efficiency, oxidative metabolism, photosynthetic parameters, and dry matter production. RESULTS: Si supply increased phenolic compounds production and reduced electrolyte leakage in seedlings provided with 0.1 mM of P. On the other hand, Si favored quantum efficiency of photosystem II as well as chlorophyll a content in seedlings supplemented with 10 mM of P. In general, Si attenuates P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters in seedlings of Eucalyptus grandis × Eucalyptus urophylla. CONCLUSION: The results of this study indicate that Eucalyptus grandis × Eucalyptus urophylla seedlings are sensitive to P deficiency and toxicity and Si has shown a beneficial effect, attenuating P nutritional disorder by reducing the oxidative stress, favoring the non-enzymatic antioxidant system and photosynthetic parameters.

The synergistic effects of soil-applied boron and foliar-applied silicon on cotton fiber quality and yield.

Studies of boron (B) and silicon (Si) synergy in cotton crops have shown promising results; however, the focus was on the foliar application of B and Si. Nonetheless, B is an element with little mobility in the plant and its best form of application is in the soil. Thus, the objective of this study was to evaluate the synergistic effect of soil applied B and foliar applied sSi on fiber quality and crop yield of cotton. For this purpose, a field experiment was carried out using cotton cultivar FM 985 GLTP. The soil's B in the experimental site is classified as low for cotton cultivation. The experiment was conducted in a randomized complete-block design, in a 3 × 2 factorial scheme, with three doses of B: 0.0 kg ha-1 (deficiency), 2.0 kg ha-1 (recommended dose), and 4.0 kg ha-1 (high dose) in the absence and presence (920 g L-1) of Si, with four replications. One week after the 4th application of Si, B and Si leaf content was determined. At boll opening, crop yield was estimated, and fiber quality analysis was realized. Boron deficiency reduced cotton yield, in 11 and 9%, compared to the application of 2 and 4 kg ha-1 of B, respectively. The presence of Si, however, increased plant yield in 5% in the treatments with 0 and 2 kg ha-1 of B, respectively. Cotton fiber length and elongation were not influenced by the B doses and Si presence. Fiber breaking strength was increased in 5% by the presence of Si and was not influenced by B deficiency. Micronaire was 8% smaller in the treatment with 0 kg ha-1 of B and 6% smaller in the absence of Si. Short fiber index was 4% greater in the plants of the treatment with 0 kg ha-1 of B. The results of this study reports that the complementation with Si via foliar application increases fiber quality by enhance breaking strength and micronaire. In conclusion, the interaction between soil-applied B and foliar-applied Si is beneficial for cotton cultivation, resulting in high cotton yield with better fiber quality.

Silicon mitigates iron deficiency in two energy cane cultivars by modulating physiological and nutritional mechanisms.

Introduction: Alkaline soils with iron (Fe) deficiency are found in many regions of the world, and the use of silicon (Si) can mitigate the damages caused by such deficiency. The aim of this study was to evaluate the effect of Si in mitigating a moderate deficiency of Fe in two energy cane cultivars. Methods: Two experiments were performed, one with the VX2 cultivar and the other with the VX3 cultivar of energy cane, which were cultivated in pots with sand and a nutrient solution. In both experiments, treatments followed a factorial scheme 2x2, designed based on the sufficiency and deficiency of Fe, being combined with the absence or presence of Si (2.5 mmol L-1), disposed in a randomized blocks design with six replicates. In the condition of Fe sufficiency, plants were cultivated in a solution containing 368 µmol L-1 of Fe, while plants cultivated under deficiency were initially submitted to cultivation with a 54 µmol L-1 concentration of Fe for 30 days, and later, with Fe complete omission for 60 days. The supply of Si was carried out by applying 15 fertirrigations with Si (via root and leaf) during the initial stage of seedling development, and after transplanting, the nutrient solution was added daily (via root). Results and discussion: Both cultivars of energy cane were sensitive to Fe deficiency in the absence of Si, impairing its growth by causing stress and pigment degradation, thus reducing the photosynthesis efficiency. The supply of Si mitigated the damages caused by Fe deficiency in both cultivars, by increasing Fe accumulation in new and intermediate leaves, stem, and roots in the VX2 cultivar, and in new, intermediate, and old leaves and stem in the VX3 cultivar, which in turn reduced stress and favored both the nutritional and photosynthesis efficiency, while increasing the dry matter production. Si by modulating physiological and nutritional mechanisms, mitigates Fe deficiency in two energy cane cultivars. It was concluded that Si can be used as a strategy to improve growth and nutrition of energy cane in environments that are susceptible to Fe deficiency.

Silicon, by promoting a homeostatic balance of C:N:P and nutrient use efficiency, attenuates K deficiency, favoring sustainable bean cultivation.

BACKGROUND: In many regions of the world, K is being depleted from soils due to agricultural intensification a lack of accessibility, and the high cost of K. Thus, there is an urgent need for a sustainable strategy for crops in this environment. Si is an option for mitigating stress due to nutritional deficiency. However, the underlying effects of Si in mitigating K deficiency C:N:P homeostasis still remains unknown for bean plants. This is a species of great worldwide importance. Thus, this study aims to evaluate whether i) K deficiency modifies the homeostatic balance of C, N and P, and, if so, ii) Si supply can reduce damage caused to nutritional stoichiometry, nutrient use efficiency, and production of dry mass in bean plants. RESULTS: K deficiency caused a reduction in the stoichiometric ratios C:N, C:P, and P:Si in shoots and C:N, C:P, C:Si, N:Si, and P:Si in roots, resulting in a decrease in K content and use efficiency and reducing biomass production. The application of Si in K-deficient plants modified the ratios C:N, C:Si, N:P, N:Si, and P:Si in shoots and C:N, C:P, C:Si, N:Si, N:P, and P:Si in roots, increasing the K content and efficiency, reducing the loss of biomass. In bean plants with K sufficiency, Si also changed the stoichiometric ratios C:N, C:P, C:Si, N:P, N:Si, and P:Si in shoots and C:N, C:Si, N:Si, and P:Si in roots, increasing K content only in roots and the use efficiency of C and P in shoots and C, N, and P in roots, increasing the biomass production only in roots. CONCLUSION: K deficiency causes damage to the C:N:P homeostatic balance, reducing the efficiency of nutrient use and biomass production. However, Si is a viable alternative to attenuate these nutritional damages, favoring bean growth. The future perspective is that the use of Si in agriculture in underdeveloped economies with restrictions on the use of K will constitute a sustainable strategy to increase food security.

New approaches to the effects of Si on sugarcane ratoon under irrigation in Quartzipsamments, Eutrophic Red Oxisol, and Dystrophic Red Oxisol.

BACKGROUND: C:N:P homeostasis in plants guarantees optimal levels of these nutrients in plant metabolism. H However, one of the causes to the effects of deficit irrigation is the loss of C:N:P homeostasis in leaves and stems that causes reduction in the growth of sugarcane. Being able to measure the impact of water deficit on C:N:P homeostasis in plants from the stoichiometric ratios of the concentrations of these nutrients in leaves and stems. This loss causes a decrease in nutritional efficiency, but can be mitigated with the use of silicon. Silicon favors the homeostasis of these nutrients and crop productivity. The magnitude of this benefit depends on the absorption of Si by the plant and Si availability in the soil, which varies with the type of soil used. Thus, this study aims to evaluate whether the application of Si via fertigation is efficient in increasing the absorption of Si and whether it is capable of modifying the homeostatic balance of C:N:P of the plant, causing an increase in nutritional efficiency and consequently in the production of biomass in leaves and stems of sugarcane ratoon cultivated with deficient and adequate irrigations in different tropical soils. RESULTS: Water deficit caused biological losses in concentrations and accumulation of C, N, and P, and reduced the nutrient use efficiency and biomass production of sugarcane plants cultivated in three tropical soils due to disturbances in the stoichiometric homeostasis of C:N:P. The application of Si increased the concentration and accumulation of Si, C, N, and P and their use efficiency and reduced the biological damage caused by water deficit due to the modification of homeostatic balance of C:N:P by ensuring sustainability of the production of sugarcane biomass in tropical soils. However, the intensity of attenuation of such deleterious effects stood out in plants cultivated in Eutrophic Red Oxisols. Si contributed biologically by improving the performance of sugarcane ratoon with an adequate irrigation due to the optimization of stoichiometric ratios of C:N:P; increased the accumulation and the use efficiency of C, N, and P, and promoted production gains in biomass of sugarcane in three tropical soils. CONCLUSION: Our study shows that fertigation with Si can mitigate the deleterious effects of deficient irrigation or potentiate the beneficial effects using an adequate irrigation system due to the induction of a new stoichiometric homeostasis of C:N:P, which in turn improves the nutritional efficiency of sugarcane cultivated in tropical soils.

Silicon as an attenuator of the toxic effects of aluminum in Schinus terebinthifolius plants / Silício como atenuador dos efeitos tóxicos do alumínio em plantas de Schinus terebinthifolius

Aluminum (Al) is highly toxic to plants, since it causes stress and inhibits plant growth. Silicon (Si) is known to mitigate the stress caused by Al in several plant species. Thus, the current study aims to investigate the soothing effects of Si on morphophysiological and photosynthetic variables, and the attributes associated with oxidative stress in Schinus terebinthifolius plants exposed to Al. Treatments have followed a completely randomized design, with three repetitions based on the following Al/Si combinations (in mM): Treatment 1: 0 Al + 0 Si; Treatment 2: 0 Al + 2.5 Si; Treatment 3: 1.85 Al + 0 Si; Treatment 4: 1.85 Al + 2.5 Si; Treatment 5: 3.71 Al + 0 Si; Treatment 6: 3.71 Al + 2.5 Si. Each sampling unit consisted of a tray with 15 plants, totaling forty-five per treatment. Shoot and root morphological variables, photosynthetic variables, photosynthetic pigments, hydrogen peroxide concentration, lipid peroxidation (MDA), guaiacol peroxidase (POD) and superoxide dismutase (SOD) enzymes, and non-enzymatic antioxidant such as Ascorbic acid (AsA) and non-protein thiol (NPSH) concentration were assessed. Root growth inhibition followed by changes in root morphological variables have negatively affected root and shoot biomass production in plants only subjected to Al. However, adding 2.5 mM Si to the treatment has mitigated the toxic effects caused by 1.85 mM of aluminum on S. terebinthifolius plants.

O alumínio (Al) é altamente tóxico para as plantas, pois causa estresse e inibe o crescimento vegetal. O silício (Si) é conhecido por atenuar o estresse causado pelo Al em diversas espécies vegetais. Assim, o presente estudo tem como objetivo investigar os efeitos suavizantes do Si sobre variáveis morfofisiológicas e fotossintéticas, e os atributos associados ao estresse oxidativo em plantas de Schinus terebinthifolius expostas ao Al. Os tratamentos seguiram um delineamento inteiramente casualizado, com três repetições baseadas nas seguintes combinações Al/Si (em mM): Tratamento 1: 0 Al + 0 Si; Tratamento 2: 0 Al + 2,5 Si; Tratamento 3: 1,85 Al + 0 Si; Tratamento 4: 1,85 Al + 2,5 Si; Tratamento 5: 3,71 Al + 0 Si; Tratamento 6: 3,71 Al + 2,5 Si. Cada unidade amostral constou de uma bandeja com 15 plantas, totalizando quarenta e cinco plantas por tratamento. Variáveis morfológicas da parte aérea e da raiz, variáveis fotossintéticas, pigmentos fotossintéticos, concentração de peróxido de hidrogênio, peroxidação lipídica (MDA), enzimas guaiacol peroxidase (POD) e superóxido dismutase (SOD) e antioxidantes não enzimáticos como ácido ascórbico (AsA) e grupos tiós não protéicos (NPSH) foram avaliadas. A inibição do crescimento radicular seguida de alterações nas variáveis morfológicas radiculares afetaram negativamente a produção de biomassa radicular e aérea em plantas submetidas apenas ao Al. No entanto, a adição de 2,5 mM de Si ao tratamento atenuou os efeitos tóxicos causados por 1,85 mM de alumínio em plantas de S. terebinthifolius.

Impact of Si on C, N, and P stoichiometric homeostasis favors nutrition and stem dry mass accumulation in sugarcane cultivated in tropical soils with different water regimes.

Studies with silicon (Si) in sugarcane indicate a greater response in productivity in plants under stress, and the underlying mechanisms of Si in the crop are poorly reported. In this context, the benefits of Si in the crop's stem production are expected to occur at the C:N:P stoichiometry level in plant tissues, benefiting plants with and without stress. However, the extension of this response may vary in different soils. Thus, this research aimed to evaluate if fertigation with Si modifies the C:N:P stoichiometry and if it can increase sugarcane's nutritional efficiency and vegetative and productive parameters. Therefore, three experiments were installed using pre-sprouted seedlings to cultivate sugarcane in tropical soils belonging to the Quartzarenic Neosol, Eutrophic Red Latosol, and Dystrophic Red Latosol classes. The treatments comprised a 2 × 2 factorial scheme in each soil. The first factor was composed without water restriction (water retention = 70%; AWD) and with water restriction (water retention = 35%; PWD). The second factor presented Si concentrations (0 mM and 1.8 mM) arranged in randomized blocks with five replications. Fertigation with Si increases the Si and P concentration, the C and N efficiency, the C:N ratio, and the dry mass production. However, it decreases the C and N concentration and the C:P, C:Si, and N:P ratios in sugarcane leaves and stems regardless of the water regime adopted in the three tropical soils. Cluster and principal components analysis indicated that the intensity of the beneficial effects of Si fertigation on sugarcane plants varies depending on the cultivation soil and water conditions. We found that Si can be used in sugarcane with and without water stress. It changes the C:N:P homeostasis enough to improve the nutritional efficiency of C, P, N, and, consequently, the dry mass accumulation on the stems, with variation in the different cultivated soils.

Addition of silicon to boron foliar spray in cotton plants modulates the antioxidative system attenuating boron deficiency and toxicity.

BACKGROUND: Boron (B) nutritional disorders, either deficiency or toxicity, may lead to an increase in reactive oxygen species production, causing damage to cells. Oxidative damage in leaves can be attenuated by supplying silicon (Si). The aim of this study was to assess the effect of increasing foliar B accumulation on cotton plants to determine whether adding Si to the spray solution promotes gains to correct deficiency and toxicity of this micronutrient by decreasing oxidative stress via synthetizing proline and glycine-betaine, thereby raising dry matter production. RESULTS: B deficiency or toxicity increased H2O2 and MDA leaf concentration in cotton plants. H2O2 and MDA leaf concentration declined, with quadratic adjustment, as a function of increased leaf B accumulation. Proline and glycine-betaine leaf concentration increased under B-deficiency and B-toxicity. In addition, production of these nonenzymatic antioxidant compounds was greater in plants under toxicity, in relation to deficient plants. Adding Si to the B spray solution reduced H2O2 and MDA concentration in the plants under nutrient deficiency or toxicity. Si reduced H2O2, primarily in B-deficient plants. Si also increased proline and glycine-betaine concentration, mainly in plants under B toxicity. Dry matter production of B-deficient cotton plants increased up to an application of 1.2 g L- 1 of B. The critical B level in the spray solution for deficiency and toxicity was observed at a concentration of 0.5 and 1.9 g L- 1 of B, respectively, in the presence of Si, and 0.4 and 1.9 g L- 1 of B without it. In addition, the presence of Si in the B solution raised dry matter production in all B concentrations evaluated in this study. CONCLUSION: Our findings demonstrated that adding Si to a B solution is important in the foliar spraying of cotton plants because it increases proline and glycine-betaine production and reduces H2O2 and MDA concentration, in addition to mitigating the oxidative stress in cotton plants under B deficiency or toxicity.

Silicon as a Sustainable Option to Increase Biomass With Less Water by Inducing Carbon:Nitrogen:Phosphorus Stoichiometric Homeostasis in Sugarcane and Energy Cane.

Climate change has prolonged periods of water deficit in sugarcane and energy cane crops. This condition induces an imbalance of the carbon (C): nitrogen (N): phosphorus (P) stoichiometric homeostasis, impairing accumulated nutrients from being converted into biomass. Silicon (Si) supplementation can mitigate the damage caused by water deficit in plants by improving the C:N:P balance, increasing C, N, and P use efficiencies and the biomass conversion, and reducing climate change effects on crops. This study assesses the beneficial effects of Si applied through fertigation associated with foliar spraying on the alleviation of damage caused by severe water deficit in sugarcane and energy cane for intermediate and long periods. In addition, the effects in maintenance of nutritional homeostasis we assessed and C, N, and P use efficiencies on sugarcane and energy cane under those conditions were increased. Four experiments were conducted during the first growth cycle of each species. The effect of fertigation associated with Si foliar spraying was evaluated by applying Si only during the seedling formation phase in sugarcane and energy cane grown under severe water deficit for 60 days after transplanting (intermediate period). Then, the effect of Si applied during seedling formation and supplemented after transplanting was evaluated in sugarcane and energy cane grown under severe water deficit for 160 days after transplanting (long period). The Si supply decreased C contents, modified the C:N:P ratio, and increased C, N, and P use efficiencies in plants of both species under water deficit at the intermediate and long periods after transplanting. The effects of applying Si through fertigation associated with foliar spraying during seedling formation mitigated the damage caused by severe water deficit in the intermediate period, which was mainly observed in sugarcane. When supplemented with Si after transplanting, the mitigating effects occurred in both species under severe long period water deficit. Therefore, the Si supply through fertigation associated with foliar spraying is a viable alternative to provide Si to the plant. It also comes with beneficial effects that partially reverse the damage to nutritional homeostasis and increase nutritional efficiency in plants under severe water deficit.

Cotton fiber quality affected by water availability and silicon application / Qualidade da fibra de algodão afetada pela disponibilidade de água e aplicação de silício

The quality of cotton fiber is a fundamental criterion for determining the commercial value of the product, being influenced by the conditions of cultivation. The study aimed to evaluate irrigated and non-irrigated cultivation systems and the management of silicon fertilization on cotton fiber characteristics. The experiment was carried out in the field in Selvíria-MS, in the 2017/2018 agricultural crop. It was adopted a randomized block design, in a 2x6 factorial scheme, with two cultivationconditions (irrigated and rainfed) and six doses of Si (0, 50, 100, 150, 200 and 400 g ha-1), with four replications. Seeds of the genotype TMG 11 WS were used. Irrigation was carried out with sprinklers spaced at 6x6 m. The application of Si via leaf was carried out at 50 and 70 days after emergence. From thecotton fiber, the characteristics of length, micronaire, strength, uniformity, elongation, reflectance, yellowing, degree of leaves, impurity and impurity particles were analyzed. The data submitted to analysis of variance by the F test, the means compared for the cultivation condition, and regression analysis for the amount of Si. The cotton fiber in irrigated cultivation showed improvement in the characteristics resistance, reflectance and yellowing.The application of Si via leaf reduced the leaf grade in the cotton fibers.

A qualidade da fibra doalgodão é critério fundamental para determinação do valor comercial do produto, sendo influenciado pelas condições de cultivo. O estudo teve como objetivo avaliarsistemas de cultivo irrigado e não irrigado e o manejo da adubação de silício sobre características da fibra do algodão. O experimento foi desenvolvido a campo no município de Selvíria-MS, na safra 2017/2018. Foi adotado delineamento em blocos ao acaso, em esquema fatorial 2x6, sendo duas condições de cultivo (irrigado e sequeiro) e seis doses de Si (0, 50, 100, 150, 200 e 400 g ha-1), com quatro repetições. Foi utilizado sementes do genótipo TMG 11 WS. A irrigação foi realizada com aspersores espaçados em 6x6 m. A aplicação de Si via foliar foi realizado aos 50 e 70 dias após a emergência. A partir da fibra do algodão, foram analisadas as características de comprimento, micronaire, resistência, uniformidade, alongamento, reflectância, amarelecimento, graus de folhas, impureza e partículas de impureza.Os dados submetidos a análise de variância pelo teste F, as médias comparadas para a condição de cultivo, e análise de regressão para quantidade de Si. A fibra de algodão em cultivo irrigado apresentou melhoria nas características de resistência, reflectância e amarelamento. A aplicação de Si via foliar reduziu o grau de folhas nas fibras de algodão.

Cotton fiber quality affected by water availability and silicon application / Qualidade da fibra de algodão afetada pela disponibilidade de água e aplicação de silício

The quality of cotton fiber is a fundamental criterion for determining the commercial value of the product, being influenced by the conditions of cultivation. The study aimed to evaluate irrigated and non-irrigated cultivation systems and the management of silicon fertilization on cotton fiber characteristics. The experiment was carried out in the field in Selvíria-MS, in the 2017/2018 agricultural crop. It was adopted a randomized block design, in a 2x6 factorial scheme, with two cultivationconditions (irrigated and rainfed) and six doses of Si (0, 50, 100, 150, 200 and 400 g ha-1), with four replications. Seeds of the genotype TMG 11 WS were used. Irrigation was carried out with sprinklers spaced at 6x6 m. The application of Si via leaf was carried out at 50 and 70 days after emergence. From thecotton fiber, the characteristics of length, micronaire, strength, uniformity, elongation, reflectance, yellowing, degree of leaves, impurity and impurity particles were analyzed. The data submitted to analysis of variance by the F test, the means compared for the cultivation condition, and regression analysis for the amount of Si. The cotton fiber in irrigated cultivation showed improvement in the characteristics resistance, reflectance and yellowing.The application of Si via leaf reduced the leaf grade in the cotton fibers.(AU)

A qualidade da fibra doalgodão é critério fundamental para determinação do valor comercial do produto, sendo influenciado pelas condições de cultivo. O estudo teve como objetivo avaliarsistemas de cultivo irrigado e não irrigado e o manejo da adubação de silício sobre características da fibra do algodão. O experimento foi desenvolvido a campo no município de Selvíria-MS, na safra 2017/2018. Foi adotado delineamento em blocos ao acaso, em esquema fatorial 2x6, sendo duas condições de cultivo (irrigado e sequeiro) e seis doses de Si (0, 50, 100, 150, 200 e 400 g ha-1), com quatro repetições. Foi utilizado sementes do genótipo TMG 11 WS. A irrigação foi realizada com aspersores espaçados em 6x6 m. A aplicação de Si via foliar foi realizado aos 50 e 70 dias após a emergência. A partir da fibra do algodão, foram analisadas as características de comprimento, micronaire, resistência, uniformidade, alongamento, reflectância, amarelecimento, graus de folhas, impureza e partículas de impureza.Os dados submetidos a análise de variância pelo teste F, as médias comparadas para a condição de cultivo, e análise de regressão para quantidade de Si. A fibra de algodão em cultivo irrigado apresentou melhoria nas características de resistência, reflectância e amarelamento. A aplicação de Si via foliar reduziu o grau de folhas nas fibras de algodão.(AU)

Silicon increases the production and quality of cherry tomato under different electrical conductivity levels / Silício aumenta a produção e qualidade de frutos de tomate cereja fertirrigado sob diferentes níveis de condutividade elétrica

The addition of high nutrient concentrations to irrigation water increases its electrical conductivity by contributing to its salinity, resulting in crop yield losses. However, in cases where stress conditions are not observed, silicon can act as a biostimulant and promote vegetative growth, fruit quality, and fruit production. From this perspective, this study aimed to evaluate the effect of fertigation with different electrical conductivity levels associated with potassium silicate on the production parameters of cherry tomatoes grown in a protected environment. The study was conducted in Bom Jesus - PI, and arranged in a randomized block design with four replications and a 6 x 2 factorial corresponding to six electrical conductivity levels (1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 dS m-1) in the absence and presence of silicon (2 mmol L-1). The variables analyzed were the number of fruits per plant, fresh and dry fruit biomass, dry biomass of stem, leaves, bunches, root, shoot, and whole plant; and chemical quality of fruits (pH, total soluble solids, titratable acidity, and the ratio of total soluble solids to titratable acidity. Silicon supplementation increased the root and shoot dry masses and improved fruits quality, thus increasing cherry tomato production (Sweet Heaven hybrid) regardless of the electrical conductivity levels.(AU)

A adição de elevadas concentrações de nutrientes à água de irrigação promove o aumento da condutividade elétrica, deixando a solução sob condições salinas, o que acarreta perdas de produtividade das culturas. No entanto, mesmo nos casos em que as condições de estresse não são evidentes, o silício pode apresentar função benéfica como elemento bioestimulante, promovendo aumento no crescimento vegetativo, na produção e na qualidade de frutos. Neste sentido, este estudo teve como objetivo avaliar o efeito de diferentes níveis de condutividade elétrica da fertirrigação, associados ao uso de silicato de potássio nos parâmetros produtivos do mini-tomate cultivado em ambiente protegido. O estudo foi realizado em Bom Jesus - PI, em delineamento de blocos casualizados, com 4 repetições, em esquema fatorial 6 x 2, correspondendo a seis níveis de condutividade elétrica (1,0; 2,0; 3,0; 4,0; 5,0 e 6,0 dS m-1), na ausência e presença de silício (2 mmol L-1). As variáveis analisadas foram: número de frutos por planta, massa da matéria fresca e seca dos frutos, massa da matéria seca do caule, folhas, cachos, raiz, parte aérea e planta inteira; e qualidade química dos frutos (pH, sólidos solúveis totais, acidez titulável e relação entre sólidos solúveis totais/acidez titulável. A suplementação de silício aumenta a massa seca da raiz e da parte aérea e melhora a qualidade dos frutos, resultando no aumento da produção de tomate cereja (híbrido Sweet Heaven), independentemente do nível de condutividade elétrica estudado.(AU)

Development of cauliflower seedlings due to the increase of silicon in substrate / Desenvolvimento de mudas de couve-flor em função do incremento de silício no substrato

The production of seedlings is an important step in the establishment of the crop, with repercussions on yield, whose application of Si can improve phytosanitary and performance characteristics. The objective of the study was to analyze the increase of silicon in substrate on the development of seedlings of Brassica oleracea var. botrytis. The experiment carried out in randomized blocks, with five amounts of silicon (0, 25, 50, 75 and 100 g kg-1of substrate) and four replications. Silicon oxide (98% SiO2) used, mixed with the substrate with subsequent filling of the polyethylene trays (128 cells) and seeding. The trays kept in a greenhouse. At 30 days after sowing, the height of seedlings, number of leaves, fresh weight of leaves and stem, dry weight of leaves, stem and root evaluated. The data subjected to analysis of variance by the F test and regression analysis. Of the variables analyzed, only the dry root mass did not show a significant difference. Quadratic models can represent the variation in components. Seedling height increased with the increase of silicon up to the dose of 75 g kg-1. Other variables showed increases up to a dose of 50 g kg-1. The increase of silicon in the substrate was efficient in the development of seedlings of Brassica oleraceavar. botrytisin an amount of up to 50 g kg-1of substrate.

A produção de mudas é etapa importante do estabelecimento da cultura, com reflexos no rendimento, cuja aplicação de Si pode melhorar características fitossanitárias e de desempenho. O objetivo do estudo foi analisar o incremento de silício em substrato sobre o desenvolvimento de mudas de Brassica oleracea var. Botrytis . O experimento foi desenvolvido em blocos casualizados, com cinco quantidades de silício (0, 25, 50, 75 e 100 g kg-1de substrato) e 4 repetições. Foi utilizado óxido de silício (98%SiO2), sendo misturado ao substrato com posterior preenchimento das bandejas de polietileno (128 células) e semeadura. As bandejas foram mantidas em casa de vegetação. Aos 30 dias após a semeadura foi avaliado a altura das mudas, número de folhas, massa fresca das folhas e caule, massa seca das folhas, caule e raiz. Os dados foram submetidos a análise de variância pelo teste F e análise de regressão. Das variáveis analisadas, apenas a massa seca de raízes não apresentou diferença significativa. Modelos quadráticos podem representar a variação dos componentes. A altura de mudas foi crescente com o incremento de silício até a dose de 75 g kg-1. Demais variáveis apresentaram acréscimos até dose de 50 g kg-1. O incremento de silício no substrato foi eficiente no desenvolvimento de mudas de Brassica oleraceavar. botrytisem quantidade até 50 g kg-1de substrato.

Development of cauliflower seedlings due to the increase of silicon in substrate / Desenvolvimento de mudas de couve-flor em função do incremento de silício no substrato

The production of seedlings is an important step in the establishment of the crop, with repercussions on yield, whose application of Si can improve phytosanitary and performance characteristics. The objective of the study was to analyze the increase of silicon in substrate on the development of seedlings of Brassica oleracea var. botrytis. The experiment carried out in randomized blocks, with five amounts of silicon (0, 25, 50, 75 and 100 g kg-1of substrate) and four replications. Silicon oxide (98% SiO2) used, mixed with the substrate with subsequent filling of the polyethylene trays (128 cells) and seeding. The trays kept in a greenhouse. At 30 days after sowing, the height of seedlings, number of leaves, fresh weight of leaves and stem, dry weight of leaves, stem and root evaluated. The data subjected to analysis of variance by the F test and regression analysis. Of the variables analyzed, only the dry root mass did not show a significant difference. Quadratic models can represent the variation in components. Seedling height increased with the increase of silicon up to the dose of 75 g kg-1. Other variables showed increases up to a dose of 50 g kg-1. The increase of silicon in the substrate was efficient in the development of seedlings of Brassica oleraceavar. botrytisin an amount of up to 50 g kg-1of substrate.(AU)

A produção de mudas é etapa importante do estabelecimento da cultura, com reflexos no rendimento, cuja aplicação de Si pode melhorar características fitossanitárias e de desempenho. O objetivo do estudo foi analisar o incremento de silício em substrato sobre o desenvolvimento de mudas de Brassica oleracea var. Botrytis . O experimento foi desenvolvido em blocos casualizados, com cinco quantidades de silício (0, 25, 50, 75 e 100 g kg-1de substrato) e 4 repetições. Foi utilizado óxido de silício (98%SiO2), sendo misturado ao substrato com posterior preenchimento das bandejas de polietileno (128 células) e semeadura. As bandejas foram mantidas em casa de vegetação. Aos 30 dias após a semeadura foi avaliado a altura das mudas, número de folhas, massa fresca das folhas e caule, massa seca das folhas, caule e raiz. Os dados foram submetidos a análise de variância pelo teste F e análise de regressão. Das variáveis analisadas, apenas a massa seca de raízes não apresentou diferença significativa. Modelos quadráticos podem representar a variação dos componentes. A altura de mudas foi crescente com o incremento de silício até a dose de 75 g kg-1. Demais variáveis apresentaram acréscimos até dose de 50 g kg-1. O incremento de silício no substrato foi eficiente no desenvolvimento de mudas de Brassica oleraceavar. botrytisem quantidade até 50 g kg-1de substrato.(AU)

Cotton fiber quality affected by water availability and silicon application / Qualidade da fibra de algodão afetada pela disponibilidade de água e aplicação de silício

The quality of cotton fiber is a fundamental criterion for determining the commercial value of the product, being influenced by the conditions of cultivation. The study aimed to evaluate irrigated and non-irrigated cultivation systems and the management of silicon fertilization on cotton fiber characteristics. The experiment was carried out in the field in Selvíria-MS, in the 2017/2018 agricultural crop. It was adopted a randomized block design, in a 2x6 factorial scheme, with two cultivationconditions (irrigated and rainfed) and six doses of Si (0, 50, 100, 150, 200 and 400 g ha-1), with four replications. Seeds of the genotype TMG 11 WS were used. Irrigation was carried out with sprinklers spaced at 6x6 m. The application of Si via leaf was carried out at 50 and 70 days after emergence. From thecotton fiber, the characteristics of length, micronaire, strength, uniformity, elongation, reflectance, yellowing, degree of leaves, impurity and impurity particles were analyzed. The data submitted to analysis of variance by the F test, the means compared for the cultivation condition, and regression analysis for the amount of Si. The cotton fiber in irrigated cultivation showed improvement in the characteristics resistance, reflectance and yellowing.The application of Si via leaf reduced the leaf grade in the cotton fibers.(AU)

A qualidade da fibra doalgodão é critério fundamental para determinação do valor comercial do produto, sendo influenciado pelas condições de cultivo. O estudo teve como objetivo avaliarsistemas de cultivo irrigado e não irrigado e o manejo da adubação de silício sobre características da fibra do algodão. O experimento foi desenvolvido a campo no município de Selvíria-MS, na safra 2017/2018. Foi adotado delineamento em blocos ao acaso, em esquema fatorial 2x6, sendo duas condições de cultivo (irrigado e sequeiro) e seis doses de Si (0, 50, 100, 150, 200 e 400 g ha-1), com quatro repetições. Foi utilizado sementes do genótipo TMG 11 WS. A irrigação foi realizada com aspersores espaçados em 6x6 m. A aplicação de Si via foliar foi realizado aos 50 e 70 dias após a emergência. A partir da fibra do algodão, foram analisadas as características de comprimento, micronaire, resistência, uniformidade, alongamento, reflectância, amarelecimento, graus de folhas, impureza e partículas de impureza.Os dados submetidos a análise de variância pelo teste F, as médias comparadas para a condição de cultivo, e análise de regressão para quantidade de Si. A fibra de algodão em cultivo irrigado apresentou melhoria nas características de resistência, reflectância e amarelamento. A aplicação de Si via foliar reduziu o grau de folhas nas fibras de algodão.(AU)

Hormesis in plants under Cd exposure: From toxic to beneficial element?

Tolerance level to cadmium (Cd) toxicity is generally associated with reductions of the internal Cd accumulation in living organisms. In plants, Cd exposure frequently triggers negative effects on their growth and productivity. However, an increased number of studies has reported the improved performance of some plant species (or their accessions/genotypes/varieties/cultivars/clones) to Cd exposure, despite Cd accumulation in their roots and shoots. These results indicate that plants have developed protective strategies to neutralize the side-effects from Cd toxicity or, more controversially, mechanisms that employ Cd as beneficial element. Here, we gathered information about Cd-induced hormetic effects on plants, and explored the potential mechanisms that allow them to have a better performance under Cd exposure. The promotion of plant development depends on both direct and indirect Cd-induced alterations in the metabolism of plants and their surround environment. In addition, the mechanisms behind the positive Cd-induced transgenerational effects were also discussed in the present paper.

Silicon reduces aluminum content in tissues and ameliorates its toxic effects on potato plant growth / Silício reduz o conteúdo de alumínio em tecidos e ameniza seus efeitos tóxicos sobre o crescimento de plantas de batata

ABSTRACT: Aluminum (Al) is highly toxic to plants, causing stress and inhibiting growth and silicon (Si) is considered beneficial for plants. This chemical element has a high affinity with Al. The aim of this study was to investigate the potential of Si to mitigate the toxic effects of Al on potato ( Solanum tuberosum L.) plants and assess whether this behavior is different among genotypes with differing degrees of sensitivity to Al. Potato plants of the genotypes SMIJ319-7 (Al-sensitive) and SMIF212-3 (Al-tolerant) were grown for fourteen days in nutrient solution (without P and pH 4.5±0.1) under exposure to combinations of Al (0 and 1.85mM) and Si (0, 0.5 and 1.0mM). After this period, shoot and roots of the two genotypes were collected to determine Al content in tissues and assess morphological parameters of root and shoot growth. Roots of both genotypes accumulated more Al than shoots and the Al-tolerant genotype accumulated more Al than the sensitive one, both in roots and in shoot. Furthermore, the presence of 0.5 and 1.0mM Si together with Al reduced the Al content in shoot in both genotypes and in roots of the Al-tolerant genotype, respectively. Si ameliorated the toxic effects of Al with regard to number of root branches and leaf number in both potato genotypes. Si has the potential to mitigate the toxic effects of Al in potato plants regardless of Al sensitivity.

RESUMO: O alumínio (Al) é altamente tóxico para as plantas, causando estresse e inibindo o crescimento e o silício (Si) é considerado benéfico para as plantas. Este elemento químico tem uma alta afinidade com o Al. O objetivo deste estudo foi investigar o potencial do Si em amenizar os efeitos tóxicos do Al sobre plantas de batata ( Solanum tuberosum L.) e avaliar se esse comportamento é diferente entre os genótipos com diferente sensibilidade ao Al. Plantas de batata dos genótipos SMIJ319-7 (sensível ao Al) e SMIF212-3 (tolerante ao Al) foram cultivadas por 14 dias em solução nutritiva (sem P e pH 4,5±0,1), sob exposição a combinações de Al (0 e 1,85mM) e Si (0; 0,5 e 1,0mM). Após esse período, parte aérea e raízes dos dois genótipos foram coletadas para determinar o conteúdo de Al nos tecidos e avaliar parâmetros morfológicos das raízes e parte aérea. Raízes de ambos os genótipos acumularam mais Al do que a parte aérea, e o genótipo tolerante ao Al acumulou mais Al do que o sensível, tanto nas raízes quanto na parte aérea. Além disso, a presença de 0,5 e 1,0mM de Si juntamente com Al reduziu o conteúdo de Al na parte aérea em ambos os genótipos e nas raízes do genótipo tolerante ao Al, respectivamente. O Si amenizou os efeitos tóxicos do Al para número de ramificações de raízes e de folhas em ambos os genótipos de batata. Si tem o potencial para amenizar os efeitos tóxicos do Al em plantas de batata, independente da sensibilidade ao Al.

Silicon reduces aluminum content in tissues and ameliorates its toxic effects on potato plant growth / Silício reduz o conteúdo de alumínio em tecidos e ameniza seus efeitos tóxicos sobre o crescimento de plantas de batata

Aluminum (Al) is highly toxic to plants, causing stress and inhibiting growth and silicon (Si) is considered beneficial for plants. This chemical element has a high affinity with Al. The aim of this study was to investigate the potential of Si to mitigate the toxic effects of Al on potato ( Solanum tuberosum L.) plants and assess whether this behavior is different among genotypes with differing degrees of sensitivity to Al. Potato plants of the genotypes SMIJ319-7 (Al-sensitive) and SMIF212-3 (Al-tolerant) were grown for fourteen days in nutrient solution (without P and pH 4.5±0.1) under exposure to combinations of Al (0 and 1.85mM) and Si (0, 0.5 and 1.0mM). After this period, shoot and roots of the two genotypes were collected to determine Al content in tissues and assess morphological parameters of root and shoot growth. Roots of both genotypes accumulated more Al than shoots and the Al-tolerant genotype accumulated more Al than the sensitive one, both in roots and in shoot. Furthermore, the presence of 0.5 and 1.0mM Si together with Al reduced the Al content in shoot in both genotypes and in roots of the Al-tolerant genotype, respectively. Si ameliorated the toxic effects of Al with regard to number of root branches and leaf number in both potato genotypes. Si has the potential to mitigate the toxic effects of Al in potato plants regardless of Al sensitivity.(AU)

O alumínio (Al) é altamente tóxico para as plantas, causando estresse e inibindo o crescimento e o silício (Si) é considerado benéfico para as plantas. Este elemento químico tem uma alta afinidade com o Al. O objetivo deste estudo foi investigar o potencial do Si em amenizar os efeitos tóxicos do Al sobre plantas de batata ( Solanum tuberosum L.) e avaliar se esse comportamento é diferente entre os genótipos com diferente sensibilidade ao Al. Plantas de batata dos genótipos SMIJ319-7 (sensível ao Al) e SMIF212-3 (tolerante ao Al) foram cultivadas por 14 dias em solução nutritiva (sem P e pH 4,5±0,1), sob exposição a combinações de Al (0 e 1,85mM) e Si (0; 0,5 e 1,0mM). Após esse período, parte aérea e raízes dos dois genótipos foram coletadas para determinar o conteúdo de Al nos tecidos e avaliar parâmetros morfológicos das raízes e parte aérea. Raízes de ambos os genótipos acumularam mais Al do que a parte aérea, e o genótipo tolerante ao Al acumulou mais Al do que o sensível, tanto nas raízes quanto na parte aérea. Além disso, a presença de 0,5 e 1,0mM de Si juntamente com Al reduziu o conteúdo de Al na parte aérea em ambos os genótipos e nas raízes do genótipo tolerante ao Al, respectivamente. O Si amenizou os efeitos tóxicos do Al para número de ramificações de raízes e de folhas em ambos os genótipos de batata. Si tem o potencial para amenizar os efeitos tóxicos do Al em plantas de batata, independente da sensibilidade ao Al.(AU)