Nitrogen, Phosphorus and Potassium Deficiency in <I>Freesia </I> spp.

Abstract

Effects of nitrogen, phosphorus and potassium deficiency on growth, development and deficiency symptoms were studied in Freesia spp. Plants were grown on the mixed media of sand, sawdust and burnt rice husk and supplied with five treatments of nutrient solutions, i.e. T1) the solution consisted of macro elements and micro elements, T2) nitrogen-deficient solution, T3) phosphorus-deficient solution, T4) potassium-deficient solution and T5) water only. Visible symptoms occurred in nitrogen deficiency treatment. Leaves were small, yellowish green and gradually turned yellow. The stalk length and corm diameter of N-deficiency treatment decreased to 31.00 and 1.18 cm, respectively. Nitrogen, phosphorus and potassium concentrations in corm of N-deficiency treatment were lower than those of control treatment. In phosphorus deficiency treatment, the mature leaves were small, curly and dark green. Emergence of inflorescence was delayed. The stalk length and corm diameter were 30.00 and 2.35 cm, respectively. N and P concentrations in corm of P-deficiency treatment were lower than those of control treatment. In potassium deficiency treatment, leaves were yellow and gradually turned brown from margin to center, then became die-back tip, and marginal scorch. The stalk length and corm diameter were 34.50 and 2.12 cm, respectively. K-deficiency clearly decreased the three nutrient contents in corm.