Effect of two compost teas as inducers of tolerance to lead and aluminum on the initial growth of maize and sorghum

Abstract

Compost teas have been reported to be inducers of tolerance to biotic and abiotic stresses in plants, but few studies have investigated heavy metal stress. We hypothesize that compost teas can mitigate the harmful effects of heavy metals in maize and sorghum. The objective of this work was to verify the effects of two compost teas, plant compost tea (PCT) and cattle manure compost tea (CMCT), as inducers of tolerance to lead (Pb) and aluminum (Al) in maize and sorghum. We produced and chemically analyzed the two compost teas and applied them to maize and sorghum exposed to Pb or Al to evaluate their effects on germination, initial growth, root morphology/architecture, antioxidant enzyme activity, and lipid peroxidation. In addition to stimulating and improving initial growth and root morphology/architecture, the two composts mitigated or nullified Pb and Al damage to several of the analyzed parameters, demonstrating biostimulant action. The effects observed are related to the chemical and microbiological composition of the compost teas, in addition to the increase in the enzymatic antioxidant metabolism of maize and sorghum.