Using halloysite nanotubes as carrier for proline to alleviate salt stress effects in sweet basil (Ocimum basilicum L.)

Through recent years, using halloysite (Hal) as a carrier for many materials has achieved great consideration. Consequently, For that reason, we aimed at using Hal as a carrier for proline (Pro) (Pro-Hal) to improve the efficiency of Pro at alleviating salinity effects.. For this purpose, Hal (50 mg L-1), Pro (50 mg L-1) and Pro-Hal (25 and 50 mg L-1) were applied on sweet basil (Ocimum basilicum L.) plants under salt stress (50 and 100 mM) conditions and agronomic, physiological and biochemical properties particularly essential oil components were investigated. The present findings of the study revealed that Pro-Hal particularly at 25 mg L-1 is the best concentration of the treatments favoring for plant performance. The treatment enhanced agronomic traits, photosynthetic pigments (chl a, b and carotenoid), chlorophyll fluorescence parameters, Pro content, antioxidant enzymes activities (APX,SOD and GP) and methyl chavicol, as the major component of sweet basil essential oil and decreased electrolyte leakage (EL), MDA and H2O2 contents under salinity. The obtained results revealed improved efficiency of Pro in Pro-Hal NPs form through improved performance of sweet basil under salinity. To conclude, Hal could be efficaciously used as a carrier for biostimulants like Pro to aid basil plants in coping with salt stress.