The first visual symptom of potassium deficiency was the marginal chlorosis on
lower leaves (Fig. 1, without K). The absence of nitrogen, phosphorus and potassium in
the nutrient solution caused chlorosis on basal leaves because these elements are mobile
and translocated to new leaves (Alcántar et al., 2007). Nitrogen is responsible for
stimulating plant vigor to participate in new tissue growth; phosphorus helps to proper
root growth and to establish young plants, and potassium is important for sugar formation
(Bravo et al., 2007).