Effect of substrate on ornamental bromeliads seedling production

Experiments were conducted with the species Aechmea distichantha and Vriesea hieroglyphica aiming to improve the management of native bromeliad production. Seedlings of V. hieroglyphica and A. distichantha were planted on substrates sphagnum, forest litter, phenolic foam flakes and carbonized rice husk (BRH), Pinus bark (PB) and Eucalyptus bark (EB) with vermiculite in proportions of 1:1, 1:2 or 1:3). The experimental design was a randomized block consisting of 4 replications with 12 plants per plot, totaling the 12 treatments. Evaluations were performed after 270 for Vriesea hieroglyphica and 125 days for Aechmea distichantha of experimentation and the variables diameter and height of seedlings, number of leaves and dry matter mass of shoot system were evaluated. Our results showed that V. hieroglyphica and A. distichantha seedlings respond different in relation to substrate composition. Vermiculite is not recommended for V. hieroglyphica and A. distichantha seedlings cultivation. Sphagnum and forest litter are the best substrate media for V. hieroglyphica and A. distichantha seedlings growth after the germination process. Key-words: Aechmea, Vriesea, Bromeliaceae, Sphagnum, Forest Litter Bromeliads are one of the most significant components of Atlantic Forest, with a preeminent contribution to its physiognomy and covering a wide number of species with ornamental potential. Bromeliads exhibit exotic forms with great diversity of colors and forms of leaves and flowers; as a result, a great landscape and floricultural potential (Ferreira et al., 2007). There are 1,342 species of bromeliads (1,177 endemic) comprised in 46 genera in Brazil (REFLORA, 2019). The floricultural industry requests an increase of new natural/exotic products in several sectors of domestic and international markets (Negrelle et al., 2012). The increase of commercial production of bromeliads could bring benefits to producers, mainly by an increase of profits to small producers, and to the environment by reducing the predatory extractivism of endangered plant species (Santos et al., 2005). Epiphytic plants require substrates with low density and, high permeability and aeration; thus, the presence of high fraction of the organic matter in the substrate should improve this characteristic and the addiction of mineral soil should be used for plants cultivated in containers, increasing the substrate porosity (Kämpf, 1992). Bromeliads use different substrates for fixation such as soil, rocks and other plants (epiphytes) (Cogliatti-Carvalho et al., 2001). The different habitats and especially the nature of the substrate influence the presence of the bromeliads, which can vary widely in leaf size and color, and flower morphology (Benzing, 2000). Bromeliads, due to the adaptations to their natural environment, have special needs when it comes to substrate (Bromeliads.info, 2019). The substrate for bromeliad commercial production should be well drained, aerated, non-compacted and slightly acidic, to allow Effect of substrate on ornamental bromeliads seedling production 317 the development of root system (Paula and Silva, 2004). In order to contribute and improve the technology for bromeliads cultivation, experiment was conducted to analyze the growth and development of the ornamental bromeliads Aechmea distichantha and Vriesea hieroglyphica seedlings cultivated on several substrates. Seeds of Vriesea hieroglyphica were collected at the Alto da Serra Biological Reserve of Paranapiacaba, Santo André, São Paulo State, Brazil, and seeds of Aechmea distichantha at the Botanical Garden of São Paulo, São Paulo, São Paulo State, Brazil. The seeds were sown in plastic boxes containing soil as substrate at a 50% shading greenhouse. The Vriesea hieroglyphica seedlings (262 days after sowing, 2.1 cm height, 2.2 cm diameter and 7.5 leaves, n=10) and Aechmea distichantha seedlings (99 days after sowing, 1.85 cm height, 3.5 cm diameter and 4.7 leaves, n=10) were planted in 128 cells polystyrene trays with sphagnum, forest litter, phenolic flake foam and mixtures of burnt rice hulls (BRH), Pinus bark (PB) or Eucalyptus bark (EB) with vermiculite in ratios of 1:1, 1:2 and 1:3 as substrates. The experiments were conducted in a greenhouse covered with translucent plastic with 50% shading. The evaluations were carried out after 270 of cultivation for Vriesea hieroglyphica and 125 days for Aechmea distichantha. The variables diameter and height of the seedlings, number of leaves and shoot system of dry matter were analyzed. The experimental design consisted of 12 treatments on a randomized block design with 4 replications and 12 seedlings per plot. Data were analyzed by variance analysis (ANOVA) and means compared by Tukey’s test (p ≤ 0.05), using the Sisvar 5.3 Statistical Software. Table 1. Diameter, height, number of leaves and dry matter of shoot system of Vriesea hieroglyphica seedlings. Treatment Diameter (cm) Height (cm) Number of leaves Dry matter of shoot system (g) Sphagnum 7.64 a 4.21 a 21.33 a 0.64 a Forest litter 7.63 a 4.06 ab 22.19 a 0.63 a Phenolic flake 5.22 b 3.32 ab 15.79 a 0.21 b BRH + vermiculite (1:1) 6.01 b 3.39 ab 16.16 a 0.29 b BRH + vermiculite (1:2) 5.72 b 3.50 ab 15.80 a 0.25 b BRH + vermiculite (1:3) 6.13 b 3.48 ab 17.38 a 0.30 b PB + vermiculite (1:1) 5.71 b 3.59 ab 14.93 a 0.21 b PB + vermiculite (1:2) 5.57 b 3.32 b 14.62 a 0.20 b PB + vermiculite (1:3) 5.70 b 3.27 b 15.06 a 020 b EB + vermiculite (1:1) 5.09 b 3.28 ab 13.66 a 0.18 b EB + vermiculite (1:2) 5.15 b 3.22 ab 13.37 a 0.19 b EB + vermiculite (1:3) 5.20 b 3.28 ab 14.71 a 0.19 b F DMS (5%) CV (%) 10.47* 1.34 9.21 2.35* 0.72 18.64 1.48 8.56 22.00 42.94* 0.13 17.63 Means accompanied by the same letter do not differ between leaves at the 5% probability level by the Tukey test. NS – Not Significant at the 5% probability level.