افزایش فعالیت آنزیم‌های دفاعی در پاسخ به کاربرد برخی مواد القا کننده‌ مقاومت در گیاهان گوجه‏ فرنگی آلوده به پژمردگی فوزاریومی

Vascular wilt disease caused by Fusarium oxysporum f. sp. lycopersici is a restrictive agent in tomato cultivation in most places of East-Azarbaijan province. In the current research first, thirty days old tomato plants were exposed to disease resistance inducing materials including salicylic acid, methyl salicylate, abscisic acid and oxalic acid two times with 5 days intervals by leaf spray and soil drench methods. Frothy eight hours after second application of inducers, plants inoculated with spore suspension of fungus. This investigation was performed as a factorial experiment in the base of completely randomized design with three replications. For study on activity of Peroxidase (PO) and Poly phenol oxidase (PPO), as the defense enzymes, sampling of plant leaves was done immediately after inoculation and also in third, fourth and seventh days after inoculation (dai). According to the results, methyl salicylate in concentrations of 100 and 200 µM and salicylic acid in concentrations of 0.5 and 1 mM respectively with 88.9, 77.8, 77.8 and 72.2 % decrease in disease severity, showed the highest effect on disease control in glasshouse conditions in leaf spray method. Abscisic acid 100 µM had the least effect (11.1%) among resistance inducers. Through root application of inducers, both methyl salicylate 100 µM and salicylic acid 0.5 mM with 77.8 % reduction and abscisic acid 100 µM with 27.8 % reduction in disease severity, showed the highest and lowest effect on disease control respectively. In both methods of application of inducers, oxalic acid with 38.9 to 61.1% decrease in disease severity had the intermediate effect on Fusarium wilt control. All of the treatments increased the activity of PO in compare with control treatment in both 3 and 7 dai and this increase was clear in leaf spray method than soil drench. Increase in activity of PPO was observed in all treatments at 7 dai in both leaf spray and soil drench methods although most of treatments shoved increase of PPO at 3 dai also in soil drench method. Salicylic acid and abscisic acid in both 3 and 7 dai, increase activity of PO more than other treatments followed by oxalic acid. Oxalic acid and abscisic acid at 3 dai and abscisic acid and methyl salicylate at 7 dai increased activity of PPO more than other treatments. Decrease in disease severity and increase in activity of defense enzymes by application of materials used in current research indicated induction of systemic acquired resistance in tomato plants against Fusarium wilt disease.