Effects of chemical production methods on the physicochemical and functional properties of chitosan [electronic resource].

Includes references.

Pathogenic isolates of Fusarium oxysporum were isolated from roots of cowpea plants naturally infected by root-rot disease. Soaking cowpea seeds (Cv. Giza 331) in different concentrations of salicylic acid (SA) for one hour increased percentage of seed germination, reduced diseased germinated seed and significantly reduced Fusarium oxysporum colonization on cowpea germinated seed. These effects were increased by increasing concentrations of salicylic acid up to 20 mM/ ml. In vitro salicylic acid was observed as fungicidal effect on the linear growth of three isolates of F. oxysporum on plate culture after amended by different salicylic acid concentrations i.e., 0,1,2,4,5,10 and 20 μM/ml. Fungicidal effect on fungal linear growth was increased by increasing concentrations of (SA). Twenty μM/ml of salicylic acid was completely suppressed linear growth of fungal isolates. In liquid culture of Dox's medium , the activities of cell wall degrading enzymes i.e., pectineases, protease and cellulases were increased at concentrations 1 and 2μM/ml salicylic acid but reduced by increasing concentration(5 and 10 μM/ml) of salicylic acid . Soaking of cowpea seed for 10 hrs of several concentrations of salicylic acid (SA) i.e., 0,1,2,5,10, and 20mM. significantly reduced root-rot incidence of cowpea plants, disease severity and significantly reduce root-rot incidence . Key words: Salicylic acid, cowpea, root-rot, F. oxysporum, lytic enzymes.

Summary in Arabic.

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