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Silicon fertigation maintains optimum growth and ion homeostasis of maize (Zea mays L.) under combined stresses of cadmium and fungus (Fusarium spp.)

Muhammad Tariq Javed: Department of Botany, Government College University

<div>Cadmium (Cd) and fungal pathogens in soil-plant systems interfere with plant growth and nutrient acquisition. Plant resistance to abiotic and biotic stresses is a complex phenomenon and involves rebalancing of nutrient homeostasis. Therefore, the current work was aimed at investigating the effect of silicon (Si) on maize growth under Cd and <em>Fusarium</em> spp. application. A pot experiment was conducted to estimate the combined effect of CdCl<sub>2</sub> stress (0, 5 and 10 mg kg<sup>-1</sup>) and <em>Fusarium</em> spp. on growth and physio-biochemistry of maize with and without 1 mM potassium silicate (K<sub>2</sub>SiO<sub>3</sub>). The cytosolic concentrations of cadmium, [Cd<sup>2+</sup>]<sub>cyt</sub>, and chloride, [Cl<sup>-</sup>]<sub>cyt</sub> were monitored from leaf protoplasts by using Leadmium Green (AM) and anion-specific MQAE dye. <em>Fusarium</em> spp. inoculation along with Cd stress significantly reduced the plant biomass and the quantity of photosynthetic pigments due to enhanced H<sub>2</sub>O<sub>2</sub>, MDA, proline levels and impaired nutrient homeostasis. Subsequently, the maize grown with Si prompted a significant increase in plant biomasses together with decreased reactive oxygen species and enhanced activity of antioxidant enzymes under the combined stresses. In parallel, the Si application conferred the plants to accumulate the nutrients (P, K, Ca, Mg, Fe and Mn) when compared with plants without Si under combined stresses. It can be concluded that Si inhibited the uptake and acropetal Cd translocation in maize which in turn improved the growth under Cd and <em>Fusarium</em> spp. stress. Silicon application also maintained the lower level of cytoplasmic Cd and Cl in maize leaf protoplasts. The outcomes are important to grow maize plants (likely by preventing the stock rot) in areas affected with <em>Fusarium</em> spp. and Cd contamination.</div>