The effect of Trichoderma harzianum on the antioxidative traits of Ocimum basilicum L. under different irrigation regimes

Taking advantage of the symbiotic relationship between plants and Trichoderma fungi is one of the ways to reduce water stress in plants. The present study was conducted in order to investigate the effect of Trichoderma fungus on the antioxidant properties of the basil medicinal plant (Ocimum basilicum L.) under water stress conditions.

This experiment was carried out in the greenhouse of the Department of Horticulture Sciences of Ahar Faculty of Agriculture and Natural Resources and laboratory studies in the basic and general laboratories of Ahar Faculty of Agriculture and Natural Resources (University of Tabriz) in 2019 in a factorial manner based on a randomized complete block design with three repetitions. The treatments included different levels of water deficit stress, including severe stress (25% of field capacity), moderate stress (50% of field capacity), mild stress (75% of field capacity), and no stress (100% of field capacity). Each pot contained a commercial mushroom species Trichoderma harzianum Na-lac with concentrations of 109 and 106 spores per milliliter as the inoculum.

The results showed that the amount of malondialdehyde, catalase and peroxidase, antioxidant activity and total flavonoid increased with the application of dehydration stress. The concentration of 106 spores per milliliter had a better impact on improving the mentioned indicators. Based on this, Trichoderma fungus proves effective when improving the antioxidant status of plants under drought stress and can prevent the effects of oxidative stress in plants by reducing the oxygen free radicals produced.

The results indicated that the use of Trichoderma mushroom in comparison with the control (without inoculation with the mushroom) can be a suitable tool to improve the physiological traits and antioxidant activities in the conditions drought stress.