Effect of nano –chelated potassium solution on some physiological and morphological characteristics of wheat under drought stress

Since potassium plays an important role in the vital activities of the plant and is one of the inhibitors of the destructive effects of drought stress. In order to investigate the effect of potassium nano-chelated on some physiological and morphological characteristics of wheat in drought stress conditions, a factorial experiment in the form of a completely randomized basic design with three replications was performed in potted culture in the greenhouse of Mohaghegh Ardabili University. The factors include the first factor of drought stress at three levels of osmotic potential (0, -4 and -8 Bar), the second factor of wheat cultivars (Rasad and Gascogn) and the third factor including nano-chelated potassium (non-application of nano-chelated potassium, 35 and 65 mg /litr). Foliar application of nano-chelated potassium and drought stress with polyethylene glycol 6000 was applied simultaneously to plants in three to five leaves stage for five days and then samples were taken from control and treated samples. Foliar application of nano-chelated potassium increased the amount of photosynthetic pigments, leaf chlorophyll index, quantum yield, height of aerial and terrestrial organs, dry and wet weight of stems and roots. Drought stress reduced maximum fluorescence, quantum yield, chlorophyll a, chlorophyll b and total chlorophyll and the average stem length, internode length, leaf length, root length and also reduced wet and dry stem weight. Among the studied cultivars, the highest amount of measured physiological and morphological traits under drought condition was related to Gascogn cultivar. In other words, this cultivar showed a better response to drought stress under foliar application of potassium nano-chelated, which indicates greater tolerance of this cultivar to drought stress. In general, the application of nano-chelated potassium at a concentration of 35 mg / l moderated the damaging effects of drought stress and increased plant defense mechanisms, especially improving the plant's photosynthetic system.