Silicon Reduces Zinc Absorption and Trigger Oxidative Tolerance Processes Without Impacting Growth in Young Plants of Hemp (Cannabis Sativa L.)

Abstract Hemp (Cannabis sativa L.) is a promising crop for non-food agricultural production on soils contaminated by moderate doses of heavy metals, while silicon, as a beneficial element, is frequently reported to improve stressed plants behavior. Using a hydroponic system, plants of Cannabis sativa (cv. Santhica 27) were exposed for one week to 100 µM Zn in the presence or absence of 2 mM Si. Zinc accumulated in all plants organs but was mainly sequestered in the roots. Additional Si reduced Zn absorption but had no impact on Zn translocation. Zn accumulation had a negative impact on biomass and chlorophyll content but additional Si did not mitigate these symptoms. Exogenous Si reduced the Zn-induced membrane lipid peroxidation (assessed by malondialdehyde quantification) and increased the total antioxidant activities estimated by the FRAP index. In the absence of Si, leaf phytochelatin and total glutathione were the highest in Zn-treated plants and Si significantly decreased their concentrations. Additional approaches using omics strategies and histological localization of element will provide interesting information regarding the interaction of Zn and Si in hemp.