The effect of carrageenan, saffron extract containing silver nanoparticles and Trichoderma harzanium on some morphophysiological and phytochemical traits of lemon balm condition (Melissa officinalis)

The use of biological stimulants in order to produce environmentally friendly biological products in conjunction with modern agriculture can increase the qualitative and quantitative growth of plants and reduce the effects of environmental stresses on them. In order to investigate the effect of Trichoderma harzanium, carrageenan and saffron extract containing silver nanoparticles on the morphophysiological and phytochemical properties of Melissa officinalis, this experiment was performed in 2020 as a randomized complete block with three replications in Fereydunkenar. This study includes ten treatments that include: Carrageenan 100 ppm, carrageenan 300 ppm, carrageenan 600 ppm, saffron extract containing silver nanoparticles 125 ppm, saffron extract containing silver nanoparticles 250 ppm, saffron extract containing silver nanoparticles 250 ppm, saffron extract containing silver nanoparticles 500 ppm, Trichoderma harzanium 100 ppm, Trichoderma harzanium 200 ppm, Trichoderma harzanium 400 ppm and distilled water (control) were applied on stages 4, 8 and 12 leaves. Morphological and phytochemical characteristics were assessed at the beginning of flowering. The results showed that the highest (6.3 cm) length and maximum (4.3 cm) leaf width were obtained from the treatment of saffron extract containing silver nanoparticles with a concentration of 125 ppm, which is 61% higher than the control treatment. Also, the highest dry weight (59 g) was related to carrageenan treatment at a concentration of 600 ppm, which was 4.9 times higher than the control treatment. Moreover, the highest (78.1%) antioxidant activity and the highest (80.4 mg/g fresh weight) anthocyanin levels were related to Trichoderma harzanium treatment at 400 ppm.