تاثیر اسید هیومیک و باکتری‌های محرک رشد روی مقاومت القایی کلزا نسبت به شته مومی کلم

In order to study the effect of spraying plant growth promoting rhizobacteria and humic acid on some secondary metabolites (total phenolic and flavonoids) on canola (cv. Jerry), an experiment was done in the research greenhouse, faculty of Agriculture, Shahid Bahonar University, Kerman, Iran and in a completely randomized design with ten replications. The treatments were used on canola plants: distilled water for control, humic acid, PGPR )Pseudomonas fluorescens strain NBTR168 + Azotobacter chroococcum strain NBTAzt2 + Azospirillum brasilense strain NBTAzoof), humic acid + PGPR and distilled water (as a control). The level of total phenolic and flavonoids in leaves of canola plants treated was measured based on Ronald & Lamia (1999) and krizek et al., 1998; respectively. Data were analyzed using the one-way analysis. Then, multiple comparisons were made using Tukey test (SPSS, 2015). Based on the results, the amount of total phenolic and flavonoids varied significantly among different fertilizer treatments (F= 10.12; df= 3, 36; P< 0.001 and F= 5.64; df= 3, 16; P= 0.008, respectively). The level of total phenolic in leaves of canola was significantly higher on treatments of PGPR and PGPR+humic acid (80.22 and 85.21 mg/g fresh weight, respectively) rather than humic acid and control (57.64 and 45.42, respectively). Also, the flavonoids in treatments of PGPR and PGPR+humic acid (0.48 and 0.58 mg/g dry weight, respectively) were significantly more than control (0.29). The amount of flavonoids in humic acid treatment did not differ significantly from the other tested treatments. The results of this study represented that total phenolic compounds and flavonoids were higher in PGPR treatments. In summary, we concluded that canola plants treated by PGPR were the least suitable host for the B. brassicae. Therefore, PGPR could induce resistance in canola against the cabbage aphid. The research could provide valuable information for integrated management of B. brassicae in the canola fields.