LAUSR

Abstract The climatic conditions of the humid tropical areas of México allow the year-round production of cut flowers and potted plants of anthurium. However, the scarce basic and applied research on tropical ornamental species limits the development of technology to increase productivity and quality. In this article, we are reporting the information as to the effect of the proportions of potassium (K+), calcium (Ca+2), magnesium (Mg+2) in the nutrient solution on anthurium growth using mixture analysis and response surface methodology. The sum of all the three cations was 20 meq L−1 and each one is expressed as a fraction of this total concentration. Response surface analysis detected that spathe and leaf areas decreased in plants fed with solutions of high proportions of Mg+2. Total shoot and root fresh weight, as well as total dry weight and root volume, also demonstrated the deleterious effects of high Mg+2. In general, the best growth occurred in two areas of the explored space; a) an area of high Ca+2, with optimum proportions ranging from 0.24–0.44 for K+, 0.54–0.68 for Ca+2, and 0.01–0.08 for Mg+2, and b) another area of high K+, on which the optimum proportions ranged 0.54–0.65 for K+, 0.25–0.29 for Ca+2, and 0.10–0.21 for Mg+2. Shoot and root K+, Ca+2, and Mg+2 concentration was significantly affected by the cation balances in the external solution, however, there was not a clear tendency as to the effect of each cation in the mixture; nonetheless, the internal K+: Ca+2: Mg+2 balances were affected by the balances in the nutrient solution, as in the shoot they were located in a very specific area of the explored space, indicating that anthurium plants accumulated more Mg+2 compared to what it is in the external solution, whereas Ca+2 was lower than that of the external solution. Plants accumulated K+ at high rates regardless of the external balance. In conclusion, the optimum nutrient solutions for anthurium may contain very wide ratios of K+ as long Ca+2 and Mg+2 are maintained at low proportion in the nutrient solution.