NUTRITION OF LACY TREE PHILODENDRON (Philodendron bipinnatifidum Schott et Endl.). PART II. NUTRIENT CONTENTS IN LEAVES

The main aim of the study conducted in the years 2007–2008 was to evaluate the effect of increasing levels of N, P, K and Mg nutrition on contents of nutrients in leaves of lacy tree philodendron (Philodendron bipinnatifidum Schott et Endl.). Analyses were conducted for five levels of macroelement content in the substrate, while maintaining a constant quantitative ratio of N : P : K : Mg = 1.0 : 0.75 : 1.25 : 0.75. Levels of nutrients in the substrate were as follows (in mg·dm-3): L-1: N 100, P 75, K 125, Mg 75; L-2: N 150, P 112, K 187 Mg 112; L-3: N 200, P 150, K 250, Mg 150; L-4: N 250, P 187, K 312, Mg 187 and L-5: N 300, P 225, K 375, Mg 225, at the constant content of microelements (in mg·dm-3): Fe 75.0, Mn 25.0, Zn 20.0, Cu 10.0, B 1.5 and Mo 2.0. The third fully developed leaf, counting from the youngest leaf on a plant, was adopted as the index part for the evaluation of the nutrient status of plants. A significant effect of the substrate fertilization level was found on the contents of N, P, K, Fe, Mn, Zn and Cu in leaves. The date of sample collection in the vegetation period was also found to have an effect on the contents of N, P and K in leaves. It was shown that the age of plants had a significant effect on Ca content in leaves of lacy tree philodendron. Optimal yield of fresh and dry mass of aboveground parts of plants, as well as the number and length of leaves, width of leaf blades, length of petioles and leaf colour intensity was on the level of L-4, in which in the index part (the 3rd leaf) of lacy tree philodendron was: (% in d.m.): N 2.99–3.55, P 0.33–0.58, K 2.99–4.72, Ca 1.44–2.08, Mg 0.33–0.39; (mg·kg-1 d.m.): Fe 50.2–59.3, Mn 60.1–68.2, Zn 49.4–57.4, Cu 28.5–32.4.