The Effect of Different Concentrations of Salicylic Acid on the Biochemical-Physiological Characteristics and Essential Oil Yield of Basil under Various Moisture Regimes

Drought stress, as a non-living limiting factor, has a highly adverse effect on the growth and productivity of crops. A study was conducted to evaluate the impact of salicylic acid on the characteristics of basil subjected to drought-stress in Karaj, Iran, during the cropping seasons of ۲۰۱۵-۲۰۱۶ and ۲۰۱۶-۲۰۱۷. Irrigation was performed at four levels: I۱ (۱۰۰% water requirement), I۲ (۸۰% water requirement), I۳ (۶۰% water requirement), and I۴ (۴۰% water requirement) in the main plots. At the same time, salicylic acid was applied as a secondary factor at five concentrations: S۱ (no application, spraying with pure water), S۲ (۵۰ µM), S۳ (۱۰۰ µM), S۴ (۱۵۰ µM), and S۵ (۲۰۰ µM) in the sub-plots. The results indicate that the application of salicylic acid has a more significant impact on increasing dry weight under drought-stress conditions. A significant increasing trend in essential oil yield was observed with the increase in salicylic acid concentration from zero to ۲۰۰ µM. Under drought-stress conditions, the total sugar and protein levels increase to enhance the plant’s tolerance to stress. Moreover, relative water content and chlorophyll index increased with the rise in salicylic acid concentration from zero to ۵۰, ۱۰۰, ۱۵۰, and ۲۰۰ micromolar. These findings suggest the positive effects of foliar application of salicylic acid, particularly at higher concentrations (۱۵۰ & ۲۰۰ micromolar), under different moisture regimes, especially drought stress, in basil plants. Hence, applying salicylic acid may be suggested as an effective management strategy for basil production under drought-stress conditions.

کلیدواژه ها:

Dry weight ، essential oil ، Ocimum basilicum L ، Water stress