Investigation the effect of chitosan foliar application on yield and qualitativetraits of Lemon balm (Melissa officinalis L.)

Biological stimulants can play an important role in increasing the essential oil of medicinalplants, through positive effects on growth and effective substances. In this research, the effectof chitosan foliar application as a biological stimulus on the quantitative and qualitative traitsof Lemon balm (Melissa officinalis L.) was investigated. This research was carried out in 2017in the greenhouse of Islamic Azad University, Karaj branch, in three replications. Theexperimental treatments included: chitosan at 4 levels, zero (control), 0.5, 1, 1.5 and 2 gramsper liter. The results show that the effects of chitosan on morphological traits including thelength of the main stem, the number of secondary stems, the diameter of the main stem, thelength of the main root, the dry weight of the stem and root, as well as chlorophyll a andchlorophyll b were significant. The maximum mentioned traits were obtained in the treatmentof 1.5 grams per liter of chitosan. The maximum percentage of essential oil was obtained in thetreatment of 2 g/l and the maximum percentage of geraniol and geranial were obtained inconcentration of 1 g/L