Induction of defensive enzymes in sunflower plants treated with agrochemicals against Macrophomina phaseolina

Abstract

This study was carried out for the estimation of polyphenols (TP) and induction of oxidative enzymes polyphenol oxidase (PPO) and peroxidase (POD) in sunflower plants through seed immersion in agrochemicals of salicylic acid (SA) and water soluble chitosan (CH) in addition to a conidial suspension of Trichoderma harzianum and then analysis of plant content of carbohydrates and protein. The highest level of PPO 253.3 U ꞏ min –1 was detected in 50 ppm SA for 6 h. Next was T. harzianum when catalyzed PPO with 193.67 U ꞏ min –1. Peroxidase was substantially catalyzed in accordance with the increment of inducers. Sunflower roots induced TP with up to 4.88 mg ꞏ g –1 in plants treated with SA at 50 ppm for 6 h and then declined with an increasing SA dose. The total carbohydrate content in leaves of 320 mg ꞏ 100 g –1 was found in treatments of CH at 50 ppm for 6 h. In roots, a carbohydrate content of 500 mg ꞏ 100 g –1 was observed using CH 75 ppm for 6 h. Trichoderma harzianum remarkably increased proteins in leaves and roots by up to 25% compared to 16.9% in the control. These results suggest that inducing the plants’ own defense mechanism by applying salicylic acid and chitosan and bio-control of T. harzianum may offer alternative methods for controlling charcoal rot of sunflower due to the creation of defensive enzymes and could support plant vigor by enhancement of its protein and carbohydrate content.

Keywords

• charcoal rot
• chitosan
• oxidative enzymes
• salicylic acid
• trichoderma harzianum