Silicon does not alleviate the adverse effects of drought stress in soybean plants

Abstract

Beneficial effects of silicon (Si) in the plants growth under conditions of drought stress have been associated with to uptake and accumulation ability of element by different species. However, the effects of Si on soybean under water stress are still incipient and inconclusive. This study investigated the effect of Si application as a way to confer greater soybean tolerance to drought stress. The experiment was carried out in 20-L pots under greenhouse conditions. Treatments were arranged in a randomized block design in a 2 × 4 factorial: two water regimes (no stress or water stress) and four Si rates (0, 50, 100 and 200 mg kg -1 ). Soybean plants were grown until beginning flowering (R1) growth stage with soil moisture content near at the field capacity, and then it started the differentiation of treatments under drought by the suspension of water supply. Changes in relative water content (RWC) in leaf, electrolyte leakage from cells, peroxidase activity, plant nutrition and growth were measured after 7 days of drought stress and 3 days recovery. The RWC in soybean leaves decreased with Si rates in the soil. Silicon supply in soil with average content of this element, reduced dry matter production of soybean under well-irrigated conditions and caused no effect on dry matter under drought stress. The nitrogen uptake by soybean plants is reduced with the Si application under drought stress. The results indicated that the Si application stimulated the defense mechanisms of soybean plants, but was not sufficient to mitigate the negative effects of drought stress on the RWC and dry matter production. Key words: Glycine max. Water deficit. Electrolyte leakage from cells. Peroxidase activity. ResumoOs efeitos benéficos do silício (Si) no crescimento das plantas sob condições de déficit hídrico têm sido associados com a capacidade de absorção e acumulação deste elemento pelas diferentes espécies de plantas. No entanto, os efeitos de Si na cultura da soja em condições de déficit hídrico ainda são incipientes e inconclusivos. Este estudo investigou o efeito da aplicação de Si, como forma de conferir maior tolerância da soja ao estresse hídrico. O experimento foi conduzido em vasos de 20 L em condições de casa de vegetação. Os tratamentos foram dispostos em um delineamento em blocos casualizados, em esquema fatorial 2 × 4: dois regimes hídricos (sem ou com estresse hídrico) e quatro doses de Si (0, 50, 100 e 200 mg kg -1 ). As plantas de soja foram cultivadas até o início do florescimento (R1) com a teor

Silicate fertilization potentiates the nodule formation and symbiotic nitrogen fixation in soybean1

“…Indeed, the Si absorbed by root cells as monosilicic acid (H 4 SiO 4 ) is deposited into leaf epidermal cells (Ma & Yamaji 2006). The significant increase in the leaf Si concentration, with the application of silicate, also has been reported in other leguminous plants, such as cowpea (Nelwamondo & Dakora 1999) and soybean (Ruppenthal et al 2016).…”

“…Freitas et al (2015) reported that application rates of 50-120 mg kg -1 of Si did not result in a significant effect on the N concentration in rice leaves. Similarly, the soybean leaf N concentration was not significantly affected by application rates of 50-200 mg kg -1 of Si (Ruppenthal et al 2016).…”

“…Calcium and magnesium silicate can be used as a corrective of soil acidity (Castro & Crusciol 2015, Sarto et al 2015 and as a Si source (Ruppenthal et al 2016). The application of Si shows beneficial effects on the growth and yield of several crops, especially those considered as Si-accumulating plants, such as rice, sugarcane, maize, sorghum and wheat (Hattori et al 2005, Kaya et al 2006, Zanão-Júnior et al 2010, Sarto et al 2015, Camargo et al 2017.…”

Salicylic acid induced changes on antioxidant capacity, pigments and grain yield of soybean genotypes in water deficit condition

“…Imposing plants to water deficit results in the accumulation of osmolytes, stress tolerance proteins and changes in antioxidant enzyme activity (Tripathi et al 2015). In soybean plant, water deficit stress reduces photosynthetic pigments, stomatal conductance, biomass, growth and finally the grain yield and its components (Hossain et al 2014;Tripathi et al 2015;Ruppenthal et al 2016). Investigation of the morpho-anatomical and physiological basis of changes in drought stress condition can be helped to select varieties with higher productivity (Martinez et al 2007).…”

Drought Resistance of 10 Ground Cover Seedling Species during Roof Greening

“…U·g -1 ·min -1 , thus it have no significant difference with the other species. In addition, the higher peroxidase enzyme activity was obtained under drought stress and can be attributed to the plant defense mechanisms against free radical formation resulting from water defcit (Ruppenthal et al, 2016). In the case of T1, Dianthus barbatus, Iris germanica…”