The biochemical response of Coffea arabica var.Borbon to chitosan and chitosan oligosaccharides(COS)was evaluated in one-year-old plants under greenhouse conditions.COS solutions were synthesized through chemical and ...The biochemical response of Coffea arabica var.Borbon to chitosan and chitosan oligosaccharides(COS)was evaluated in one-year-old plants under greenhouse conditions.COS solutions were synthesized through chemical and physical hydrolysis using acetic acid,hydrogen peroxide,and microwave irradiation.The obtained COS had an average molecular weight(Mw)of 3549.90±0.33 Daltons(Da),a deacetylation degree(DD)of 76.64±1.12%,and a polymerization degree(PD)of 18.91±0.0018.Solutions of chitosan and COS were applied to C.arabica var.Borbon at concentrations of 0.25,0.5,and 1 wt%.The experimental design was conducted using a completely randomized design with four replications.The biochemical responses assessed included soluble protein content,phenylalanine ammonia-lyase(PAL),chitinase,β-1,3-glucanase,peroxidase,catalase,and chlorophyll fluorescence.The application of COS demonstrated significant differences(α=0.05)in protein concentration,with the activity ofβ-1,3-glucanase,chitinase,and catalase being 1.5,7.5,and 3.9 times higher,respectively,while showing similar behavior to chitosan in PAL activity,both up to 4.4 times higher than the distilled water control and lower than chitosan in peroxidase activity.Treatments with chitosan yielded a higher photochemical efficiency of Photosystem II(PSII).The application of COS suggests a viable foliar alternative to active plant defense mechanisms without the risk of phytotoxicity.展开更多
文摘The biochemical response of Coffea arabica var.Borbon to chitosan and chitosan oligosaccharides(COS)was evaluated in one-year-old plants under greenhouse conditions.COS solutions were synthesized through chemical and physical hydrolysis using acetic acid,hydrogen peroxide,and microwave irradiation.The obtained COS had an average molecular weight(Mw)of 3549.90±0.33 Daltons(Da),a deacetylation degree(DD)of 76.64±1.12%,and a polymerization degree(PD)of 18.91±0.0018.Solutions of chitosan and COS were applied to C.arabica var.Borbon at concentrations of 0.25,0.5,and 1 wt%.The experimental design was conducted using a completely randomized design with four replications.The biochemical responses assessed included soluble protein content,phenylalanine ammonia-lyase(PAL),chitinase,β-1,3-glucanase,peroxidase,catalase,and chlorophyll fluorescence.The application of COS demonstrated significant differences(α=0.05)in protein concentration,with the activity ofβ-1,3-glucanase,chitinase,and catalase being 1.5,7.5,and 3.9 times higher,respectively,while showing similar behavior to chitosan in PAL activity,both up to 4.4 times higher than the distilled water control and lower than chitosan in peroxidase activity.Treatments with chitosan yielded a higher photochemical efficiency of Photosystem II(PSII).The application of COS suggests a viable foliar alternative to active plant defense mechanisms without the risk of phytotoxicity.
