Phenolic compounds in embryos of triticale caryopses at different stages of development and maturation in normal environment and after dehydration treatment

Abstract

High performance liquid chromatography analysis revealed the presence of five phenolic acids in embryos of triticale caryopses (vanillic, caffeic, p-coumaric, ferulic and sinapic). Free phenolic acids reached the highest level at the early stages of development when germination was the lowest and decreased considerably in embryos at the final stage of grain maturation when germination was the highest. Revealing inverse correlation between the contents of free phenolic acids in developing embryos and intensity of precocious germination may indicate a role of phenolic acids in preventing pre-harvest sprouting in cereals. Total content of phenolic acids in embryos (i.e. free, and liberated from soluble esters and glycosides) increased gradually to 43DAF and decreased at full ripeness, whereas the content of total phenolics fluctuated slightly in embryos during development and ripening of caryopses. Enforced dehydration of unripe triticale caryopses stimulated germination both in embryos and whole grains. During the enforced dehydration treatment, a decrease in total content of both phenolic acids and phenolic compounds in embryos of triticale caryopses at different stages of development and maturation was observed. It should be stressed, that a number of naturally occurring phenolics are known to inhibit the germination of cereal grains. A possible role for phenolics in preventing pre-harvest sprouting and acclimation to dehydration in cereals is discussed.