EFFECTS OF NANO-POTASSIUM AND POTASSIUM SULFATE FERTILIZERS AND SALICYLIC ACID ON THE MORPHO-PHYSIOLOGICAL TRAITS OF MARIGOLD, CALENDULA OFFICINALIS L., UNDER DROUGHT STRESS

Abstract

Effects of nano-potassium and potassium sulfate fertilizers and salicylic acid on some morpho-physiological traits of marigold under drought stress were investigated in a factorial experiment based on a randomized complete block design with three replications in the research greenhouse of Gorgan Islamic Azad University in 2019. Experimental treatments were irrigation at two levels, application of potassium fertilizer at two levels of potassium (K)-nano chelate and potassium sulfate (PS), and salicylic acid (SA) at three levels of zero, 1, and 2 mM. Measured traits were plant height, shoot and root fresh and dry weights, number of leaves, peroxidase activity, and the contents of proline and glycine betaine (GB). Drought stress resulted in decreased plant height, shoot and root fresh and dry weights, and the number of leaves, but it increased peroxidase activity and the contents of proline and GB. Application of K-nano chelate increased shoot fresh weight, shoot and root dry weights, peroxidase activity, and the contents of proline and GB. Morphological traits decreased significantly by the drought stress, but the application of K-nano chelate and PS fertilizers and SA improved growth and physiological indices under stress conditions.