Is Potassium (K+) Key to Enhancing Plant Growth?

More intensive farming practices to meet growing food demands are leaving much of the soils depleted of nutrients. Much is known about Nitrogen and Phosphorus status in soils and its effect on plants however information is lacking on Potassium’s role in defending plants against abiotic stress. Potassium, an essential plant nutrient plays an important role in a number of physiological and biochemical processes that link to resistance to abiotic stresses. The focus of the study was to investigate the relationship between the supra and suboptimal potassium status of cucumber (Cucumis sativus L.) and its effect on the growth and development. Cucumber seedlings were treated with six different mM concentrations of potassium (1, 2, 4, 6, 8, and 12) for 70 days. The leaf chlorophyll content, number of fruits, fresh and dry weights increased with an increase in K supply from 1 to 6 mM and, highest was in treatment supplied with 6 mM potassium.  Treatments above 6 mM responded negatively to increase in potassium supply. The substrate pH ranged from 6.05 to 6.12. The substrate pH increased linearly with an increase in K supplied from 0.8 to 3.4 dS.cm^-1 and it could be contributing factor for decline in growth at 8 and 12 mM potassium concentration.