Plant Process and Function

en The role of potassium foliar spray in improving the effects of drought stress in ‎Stevia rebaudiana: Quantitative and qualitative yield, high-consumption ‎elements, and some physiological traits The role of potassium foliar spray in improving the effects of drought stress in ‎Stevia rebaudiana: Quantitative and qualitative yield, high-consumption ‎elements, and some physiological traits تنش خشكي Droughts Stress پژوهشي Research <div style="text-align: left;">Drought stress (DS) is a significant constraint on agricultural productivity. Managing nutritional elements, such as potassium (K), can reduce the effects of drought stress. To investigate the impact of DS and K foliar spraying on the yield and some leaf compounds of Stevia rebaudiana B., a field experiment was performed as a factorial form in a randomized complete block design with three replications in 2017-2018. The first factor consists of three levels of DS: Irrigation after the evaporation of 40 mm, 70 mm, and 100 mm from a Class A evaporation pan. The second factor includes three levels of foliar potassium (K) spray, applied at concentrations of 0%, 1%, and 1.5%, using potassium sulfate as the source. After preparing the land, seedlings were planted by hand at intervals of 50 cm by 75 cm in planting rows, resulting in a density of 2.5 plants per square meter on March 6. The results showed that both the zero-stress treatment and the foliar spray of 1.5% potassium (K) resulted in the highest yields of dry matter (1280.72 kg/ha) and leaf yield (846.47 kg/ha). This was not significantly different from the zero-stress treatment with a foliar spray of 1% potassium (1279.88 kg/ha). Additionally, the highest percentage of stevioside was observed under severe stress conditions, where the application of potassium foliar spray did not influence the stevioside percentage. Considering the positive effects of potassium foliar spray on both dry matter yield and leaf yield, as well as its ability to reduce potential damage caused by drought, it is recommended to use potassium foliar spray to achieve high yields in stevia plants under drought conditions.</div> Drought stress (DS) is a significant constraint on agricultural productivity. Managing nutritional elements, such as potassium (K), can reduce the effects of drought stress. To investigate the impact of DS and K foliar spraying on the yield and some leaf compounds of Stevia rebaudiana B., a field experiment was performed as a factorial form in a randomized complete block design with three replications in 2017-2018. The first factor consists of three levels of DS: Irrigation after the evaporation of 40 mm, 70 mm, and 100 mm from a Class A evaporation pan. The second factor includes three levels of foliar potassium (K) spray, applied at concentrations of 0%, 1%, and 1.5%, using potassium sulfate as the source. After preparing the land, seedlings were planted by hand at intervals of 50 cm by 75 cm in planting rows, resulting in a density of 2.5 plants per square meter on March 6. The results showed that both the zero-stress treatment and the foliar spray of 1.5% potassium (K) resulted in the highest yields of dry matter (1280.72 kg/ha) and leaf yield (846.47 kg/ha). This was not significantly different from the zero-stress treatment with a foliar spray of 1% potassium (1279.88 kg/ha). Additionally, the highest percentage of stevioside was observed under severe stress conditions, where the application of potassium foliar spray did not influence the stevioside percentage. Considering the positive effects of potassium foliar spray on both dry matter yield and leaf yield, as well as its ability to reduce potential damage caused by drought, it is recommended to use potassium foliar spray to achieve high yields in stevia plants under drought conditions. Foliar nutrition, Leaf yield, Macro elements, Proline, Stevioside Foliar nutrition, Leaf yield, Macro elements, Proline, Stevioside 25 34 http://jispp.iut.ac.ir/browse.php?a_code=A-10-1409-2&slc_lang=en&sid=1 Razieh Tofangsazpour Razieh Tofangsazpour r.tofangsazpuor@gmail.com No Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural ‎Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural ‎Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Abdolmahdi Bakhshandeh Abdolmahdi Bakhshandeh Abakhshandeh66@yahoo.com No Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural ‎Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural ‎Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Alireza Abdali Mashhadi Alireza Abdali Mashhadi alireza.abdali1384@gmail.com No Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural ‎Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Mohammadreza Moraditelavat Mohammadreza Moraditelavat moraditalavat@ramin.ac.ir No Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Amin Lotfi Jalal-Abadi Amin Lotfi Jalal-Abadi aminlotfi@asnrukh.ac.ir Yes Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran Professor, Department of Plant Production Engineering and Genetics, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran