Silicon Supplied via Root or Leaf Relieves Potassium Deficiency Effects in Common Bean

Potassium (K) deficiency affects physiological performance and decreasing vegetative growth in common bean plants. However, silicon (Si) supplied via nutrient solution or foliar application may relieve nutritional stress. Thus, two experiments were carried out: initially, a test was performed to determine the best source and concentration of leaf-applied Si. Subsequently, the chosen Si source was applied via nutrient solution or via leaf to verify if it is efficient in alleviating the effects caused by K deficiency. To that end, a completely randomized 2 x 3 factorial design was used, with two levels of K: deficient (0.2 mmol L− 1 of K) and sufficient (6 mmol L− 1 of K); and Si: via nutrient solution (2 mmol L− 1 of Si) or foliar spray (5.4 mmol L− 1 of Si) and control (0 mmol L− 1 of Si). In the first experiment, foliar spraying with sodium silicate and stabilized potassium at a concentration of 5.4 mmol L− 1 was better in favoring the physiology of bean plants. In the second experiment, K deficiency without the addition of Si compromised the plant's growth. Si applied through nutrient solution or foliar spray relieved K deficiency stress, increasing chlorophylls and carotenoids content, photosynthetic activity, water use efficiency and vegetative growth.