Role of silicon fertilization in the resilience of chestnut plant to abiotic and biotic stresses and fruit productivity and quality

Climate change is a current issue that influences world agricultural production. In this context, extreme temperatures and low rainfall during the summer hamper the development and growth of the chestnut tree, thereby increasing its susceptibility to disease and pests, affecting the production of chestnut. In the future, plants will be exposed to various abiotic and biotic stresses affecting their defense response. Several studies refer to the importance of applying silicon in agriculture as an efficient solution in promoting the tolerance of many crops to abiotic and biotic stresses, highlighting its great agronomic value. Silicon application enhances plant growth and productivity, increases drought and temperature resilience provides greater cell wall thickness and also aids in the defense against pathogens attacks. For these reasons, the impact of silicon application on chestnut plants under water stress was evaluated; inoculation with Phytophthora cinnamomi and under infection by Cryphonectria parasitica. In these studies, the plants were treated with potassium silicate silicon SiK® at concentrations 0, 5, 7.5 and 10 mM. Throughout the work, ecophysiological, biochemical and anatomical parameters were evaluated. The studies have shown that silicon fertilization promoted greater tolerance of plants to the biotic stresses studied (ink disease and chestnut blight) through a faster and more efficient host defense response induced by increased synthesis of phenolic compounds with antifungal properties and in increasing enzyme activity. The biochemical defense provided by silicon was accompanied by the action of phytoliths, which act as a mechanical barrier that makes it difficult for hyphae to enter the tissues, reducing/preventing the development of pathologies. On the other hand, studies under abiotic stresses showed that the application of silicon promoted chestnut resilience to heat and drought. Silicon promoted the reduction of water loss by evapotranspiration, also reduced lipid peroxidation and H2O2 production, reducing oxidative damage through increased antioxidant activity. Finally, that is found that application of silicon provides a reduction in the number of aborted fruits, increases the number of healthy nuts and also reduces fruit water loss after harvest, thus allowing the fruits to be preserved for a longer period of time, increasing its commercial value. In conclusion, silicon application can be a powerful tool in chestnut culture because it induces physical and biochemical changes that help plants increase their resilience to drought, high temperature, as well as inoculation of P. cinnamomi and C. parasitica. For these reasons, it is important that Si is applied to agriculture more extensively because, in addition to increasing plant resistance, it does not pollute the environment and has no adverse effects on human health.