Impact d’une disponibilité contrastée en silicium sur le développement de plants de maïs (Zea mays L.) cultivés en système hydroponique

Description of the subject. Silicon is a beneficial chemical element, considered as “quasi-essential” for plant growth and production. Seven of the top ten most important crops in the world are silicon-accumulating Poaceae species, maize being one of them. However, the beneficial role of Si for plants is still under debate. Objectives. In this study, we evaluate the impact of three silicon concentrations in a nutrient solution on the development of maize plants. Method. We cultivated maize plants in a hydroponic system allowing to provide three contrasted silicon fertilization: (1) a silicon-deficient medium (0.05 mM); (2) a medium silicon supply, comparable to what can be found in an agricultural soil (0.6 mM); and (3) a highly enriched silicon medium (2.0 mM), named Si-, Si+ and Si++, respectively. Results. We found the silicon contents in aerial parts of plants to be strongly impacted by the concentration available in the growing medium: 0.247 g Si·kg-1 DW (Si-), 5.707 g Si·kg-1 DW (Si+) and 8.731 g Si·kg-1 DW (Si++). However, neither plant size nor phenology were impacted by silicon supplies. Both fresh leaf weight (+15.5%) and dry leaf weight (+13.5%) increased under Si++ (compared to Si-). Finally, neither root fresh weight nor root dry weight was impacted by Si fertilization. Conclusions. We conclude that increase in the concentration of Si in nutrient solution leads to increase in fresh and dry weight of the maize leaves.