Growth and volatile compounds of the medicinal plant Melissa officinalis L. as affected by salicylic acid and salinity

Salinity is an important environmental factor limiting plant growth and development. Salicylic acid is a phenolic compound and plant growth regulator that mitigates the adverse effects of salinity stress. This study was conducted to evaluate the effects of salicylic acid on the growth and physiological responses of the Melissa officinalis L. grown under salt stress. First, sodium chloride at 0, 25 and 75 mM concentrations were added as irrigation to the soil of 40 days plants and then, different concentrations of salicylic acid (0, 150 and 300 ppm) were sprayed on the plants twice during the growth period. After 45 days, the interaction of salicylic acid and salinity on growth, photosynthetic pigments, osmotic adjustments and volatile compounds were studied. The results of the analysis of variance showed that fresh and dry weights, chlorophyll and carotenoids contents of seedlings decreased significantly under salt stress while proline contents increased significantly. Application of salicylic acid decreased effects of stress and at 300 ppm concentration, with 75 mM of NaCl increased proline as a tolerance index. Citronella with 52.17 percent of the total volatile compounds had the highest concentration in the aerial parts of the plant. As salinity and salicylic acid levels increased some of the volatile compounds such as Geranial, Neral, karahanaenone, and Geraniol were decreased, whereas Caryophyllene and Cis-pinocarrol increased slightly. Therefore, salicylic acid helps plants to tolerate salt stress with elevated proline and change content and type of volatile compounds

کلیدواژه ها:

Gas chromatography-mass spectrometry ، Citronella