Co-aplicação de extrato de alga marinha e silício: efeito na esporulação, colonização micorrízica e crescimento inicial de Mimosa caesalpiniaefolia

Abstract

Seaweed extracts (EAM) and silicon (Si) are known to improve physiological processes and plant growth under adverse conditions. However, little is understood about how the combination of these two factors influences the sporulation of arbuscular mycorrhizal fungi (AMF), mycorrhizal colonization (MC), and plant species growth. In this context, the objective was to evaluate the effect of co-application of EAM and Si on the abundance of AMF spores in the soil (AESP), mycorrhizal colonization, and initial growth of Mimosa caesalpiniaefolia. A greenhouse experiment was conducted using Mimosa caesalpiniaefolia grown in soil subjected to either the application or non-application of EAM, along with three levels of Si (0 mg kg⁻¹, 150 mg kg⁻¹, and 300 mg kg⁻¹ of Si) over a period of 70 days. The following parameters were evaluated: shoot height (SH), stem diameter (SD), number of leaves (NL), root length (RL), shoot dry mass (SDM) and root dry mass (RDM), AMF spore abundance in the soil (AESP), mycorrhizal colonization (MC), soil pH, soil electrical conductivity, Si content in the shoot, root, and soil; phosphorus (P), sodium (Na), and potassium (K) content in the shoot and soil. Mimosa caesalpiniaefolia plants exhibited greater SH, SD, NL, and SDM when Si and EAM were applied, while RDM and RL were lower at higher Si application levels. MC was highest with the application of 150 mg kg⁻¹ of Si in the presence of EAM, whereas AESP decreased with increasing Si levels in the presence of EAM. Si content in the shoot was highest with the application of 300 mg kg⁻¹ of Si combined with EAM, while in the root, the highest Si values were influenced only by the application of 300 mg kg⁻¹ of Si. Na content in the shoot was higher at 300 mg kg⁻¹ of Si without EAM, whereas K content was highest at 150 mg kg⁻¹ of Si in the presence of EAM. P content in the shoot was not influenced by the treatments. In the soil, pH, EC, and Na values were higher at 300 mg kg⁻¹ of Si, while K and P levels in the soil solution were lower at this same level of Si without EAM. Our results suggest that the co-application of EAM and Si promotes the initial growth of Mimosa caesalpiniaefolia and may modulate mycorrhizal symbiosis. However, proper management is essential to maximize its benefits for both the plant and the soil.