Fig. 1

Phenylalanine ammonia-lyase (PAL), Peroxidase (POX) and β-1,3glucanase activities in orange leaves from untreated (control) and treated plants with humic substances (HS) and HS + plant growth-promoting bacteria. A: cv Baia with two years old and B: cv Seleta with one year old. Leaflets were harvested 48 h after treatments and then monthly for six months