Response of Growth and Chemical Constituents of Kalanchoe Blossfeldiana Transplants Grown Under Shade Net House to Growing Media and L-Tryptophan

Abstract

Aiming: To evaluate the effect of various growing media types and foliar application rates of tryptophan (Trp) on the growth parameters and chemical constituents of Kalanchoe blossfeldiana, Materials and Methods: a pot experiment was conducted under a shade net house at the roof of the Horticulture Department, Faculty of Agriculture, Zagazig University, from September 28, 2023, to February 25, 2024 (2023/2024 winter season). The experimental treatments comprised six media mixtures formulated at equal volume ratios (sand: clay, vermiculite: clay, sand: peat moss, vermiculite: peat moss, sand: vermiculite: clay, and sand: vermiculite: peat moss), four tryptophan concentrations (0.0, 100, 150, and 200 ppm), and their combinations. Results: Cultivating Kalanchoe transplants in a sand: clay medium, followed by a sand: vermiculite: clay mixture, resulted in statistically significant increases in plant height, plant and root dry weights, total nitrogen (N), and phosphorus (P) content compared to other evaluated media. Conversely, transplants grown in vermiculite: clay produced a significantly higher leaf count per plant, whereas the highest concentrations of total carbohydrates and potassium (K) were recorded in the sand: clay medium. Foliar spraying with 200 ppm Trp significantly enhanced overall vegetative growth and chemical constituent accumulation compared to lower application rates. Recommendation: Overall, combining a sand: clay growing medium with a 200 ppm tryptophan foliar spray is recommended as the most effective agronomic practice to optimize the growth and flowering performance of Kalanchoe blossfeldiana.