Abstract

Barley (Hordeum vulgare) is one of the main cereals grown for animal feeding and for human consumption. However, presence of aluminium (Al) toxic on soils is an important growth-limiting factor for plants decreasing yield, quality and development of barley. Although silicon (Si) exerts various functions to plants, it has not considered as an essential element for growth. It has been demostrated that Si attenuates Al toxicity, as well as it promotes the production of phenolic compounds with antioxidant or structural funtion such as lignin. The aim of this research was to evaluated the effect of silicon on phenols with antioxidant or structiral function in barley plantas under aluminium stress. A hydroponic experiment was conducted by using barley cv. Sebastian (Al-Tolerant) and cv. Scarlett (Al-sensitive), applying Al treatments (o and 0.2 mM Al) combined with Si treatments (0 and 2 mM) for 21 days. At harvest, Al concentration, total phenols, lipid peroxidation and DPPH in roots and shoots were determined. Aluminium concentration was increased for the two cultivars when 0.2 mM Al were applied and decreased when Al was supplied in combination with Si. The highest concentration of soluble phenols and radical scavenging activity was founf when Si was added in both cultivars. Whereas, lipid peroxidation of two studied cultivars decreased in roots by Si supply compared with the control and Al treated plants. Finally, Laser Scanning confocal Microscopy showed that lignin accumulation showed high intensity when Si and Al were applied separately or in combination.