Impact of L-phenylalanine ammonia-lyase inhibition on winter triticale (× Triticosecale Wittmack) at early developmental stages

A b s t r a c t. Climate change, particularly increasingly frequent autumn droughts, poses a significant threat to winter triticale by limiting seedling emergence and early development.Various strategies are being investigated to enhance winter triticale at the early stages of development.Therefore, this study aimed to investigate the impact of L-phenylalanine ammonia-lyase (PAL) inhibition on seed germination and very early seedling development, with a particular focus on carbon allocation towards carbohydrate biosynthesis and its subsequent utilization in growth processes.4-Hydroxybenzoic acid hydrazide (HBH) was used as a PAL inhibitor.Osmotic potential, phenolic and carbohydrate content, photosynthetic pigments, antioxidant potential, blue fluorescence intensity, chlorophyll fluorescence, stomatal conductance, and coleoptile length were analyzed.The PAL inhibitor reduced the accumulation of phenolic compounds in the coleoptiles, accompanied by an increase in soluble sugar content and osmotic potential.The decrease in phenolic levels was supported by decrease in blue fluorescence emission.HBH lowered the antioxidant potential of coleoptiles and roots, while elevating the antioxidant potential of germinating seeds.The inhibitor suppressed coleoptile elongation and negatively affected the chlorophyll content, stomatal conductance, and the photosynthetic apparatus activity of the emerging first true leaf.Our results showed that PAL inhibition alters carbon allocation and negatively affects early seedling development.K e y w o r d s