Effect of Chitosan of Different Origins on the Contents of Phenolic Antioxidants in Fragaria Ananassa Duch. Leaves

Plants are subjected to an enormous number of biotic and abiotic environmental stresses during their life cycle. The responses to different stresses are very complex and include changes at the transcriptome, cellular, and physiological levels. The recognition of inductors and signaling molecules is one of the ways of inducting the plant's own defense mechanisms. The response reactions of Fragaria ananassa Duch. plants treated with chitosan of different origins and molecular weight were studied in our experiment. The plants exhibited highly reactive physiological responses. Chitosan with low molecular weight (ChI) caused intensification of phenylpropanoid synthesis, tannins formation and changed daily dynamics of secondary metabolism. Within twelve hours after treatment with ChI preparation, total phenolic and antioxidant amounts in leaves increased by 1.9 and 3.2 times respectively. Unlike ChI, the solution of high molecular weight chitosan (ChII) induced in leaves a sharp decrease of free and loosely-bound with cell walls phenolic compounds. We observed differences of plant primary response reactions to chitosan treatment. They depend on the origin of chitosan, its molecular weight and degree of deacetylation.