Association of silicon supply and arbuscular mycorrhizal fungi inoculation in sweet corn subjected to different water reposition levels.

Abstract

Drought affects plant key processes, being a main constraint for food security worldwide. Arbuscular mycorrhizal fungi (AMF) and Silicon (Si) are well-known strategies to mitigate drought stress in plants. However, lacks of information regarding it is association in sweet corn plants. We hypothesized that Si and AMF association could be a potential way to mitigate drought stress in sweet corn. A greenhouse experiment was conducted under a triple factorial (5x2x2) scheme, including five water reposition levels (40, 60, 80, 100 and 120% of reposition), two AMF inoculation levels (presence/+AMF, and absence/-AMF) and two Silicon (Si) supply levels (presence/+Si and absence/-Si). We evaluated plant growth, yield, photosynthesis parameters (SPAD, and Fv/Fm), Si content in leaves and mycorrhizal colonization. Water restriction led to reduction in sweet corn performance. In severe drought stress conditions (40% of reposition), AMF inoculation improved growth (shoot and root) and Si supply improved SPAD. Overall, AMF and Si, isolate or in association, increased SPAD and efficiency of PSII. In non-Si-supplied plants, AMF increased Si content in leaves, but no AMF-mediated uptake of Si was found in Si-supplied plants. In severe drought conditions, AMF and Si may be potential ways to mitigate the defective effects of drought. However, in front of the complexity of AMF-plant-Si-environment interactions, further research needs to be conducted in order to investigate better these effects.