Effects of spraying salicylic acid and jasmonic acide on the morphological and biochemical characteristics of Chamomile (Matricaria Chamomilla L.) under Bushehr climate conditions

Heat stress causes morphological, physiological and biochemical changes in plants and affects plant growth. Given the mediator role of plant hormones in heat stress, this research was aimed to study the effect of spraying salicylic acid and jasmonic acid on the morphological and biochemical characters of Chamomile (Matricaria chamomilla L. cv: Bona) under natural heat stress conditions. This experiment was carried out as completely randomized blocks design with 3 replications. Four levels of salicylic acid (0, 12.5, 25, 50 mg.l-1) and four levels of jasmonic acid (0, 1, 1.5, 2 mg.l-1) were applied as treatments. The planting date was set in a way that more stages of plant growth and flowering period faced with heat stress. The morphological traits including plant height, capitol diameter, flower fresh weight, flower dry weight, and biochemical traits including essential oil and chamazulen percentage were studied. The analysis of variance showed that interaction effect of hormone salicylic acid and jasmonic acid on the flower fresh weight and chamazulen percentage was significant. In addition, the effect of jasmonic acid on chamazulen percentage was statistically significant. The best chamazulene percentage was observed in 2 mg.l-1 jasmonic acid treatment under heat stress.