©2023 International Society of Arboriculture 160 Alves et al: Influence of Protected Environments and Reflector Material on Oiti Seedlings of 35% shading; (A3) agricultural screenhouse with a black screen of 30% shading; and (A4) agricultural screenhouse with a black screen of 18% shading. All environments had dimensions of 8 m wide × 18 m long. The A1 environment had a zenith opening, side and front closures at 90°, a black screen with 30% shading, and a ceiling height of 3.5 m. The screened environments A2, A3, and A4 had a ceiling height of 4.0 m, and the side and front screens closed at 45°. Inside the protected environments, production sys- tems were tested with (RM) and without reflective material (WRM) on the cultivation benches using aluminized thermo-reflective screen (Aluminet®). The seeds were collected from the fruits of parent plants on the university campus in Cassilândia-MS. Sowing took place on 2019 December 10 in polyeth- ylene bags (15 × 25 cm) with a capacity of 1.8 L using Carolina Soil® substrate (Carolina Biological Supply Company, Burlington, North Carolina, USA). Two seeds per bag were sown. Emergence was verified 14 days after sowing (DAS). After emergence stabiliza- tion, thinning was performed, leaving one seedling per container. Irrigation was performed daily accord- ing to the needs of the crop without soaking the sub- strate using a suspended micro-sprinkler system with Netafim SpinNet™ emitters (Netafim, Fresno, Cali- fornia, USA). At 40, 55, and 70 DAS, the stem diameter (SD, mm) was measured with a digital caliper (SD1 = stem diameter at 40 DAS; SD2 = stem diameter at 55 DAS; SD3 = stem diameter at 70 DAS); the seedling height (SH, cm) was assessed with a millimeter ruler, mea- suring the distance from the soil surface to the apex of the apical meristem of the stem (SH1 = seedling height at 40 DAS; SH2 = seedling height at 55 DAS; SH3 = seedling height at 70 DAS); and the number of leaves (NL) was counted (NL1 = number of leaves at 40 DAS; NL2 = number of leaves at 55 DAS; NL3 = number of leaves at 70 DAS). Also, the relationship between seedling height and stem diameter (H:D1 = ratio between seedling height and stem diameter at 40 DAS; H:D2 = ratio between seedling height and stem diameter at 55 DAS; H:D3 = ratio between seedling height and stem diameter at 70 DAS) and absolute growth rates between the collection intervals of seed- ling height data (AGR, cm day−1) were determined (Equations 1, 2, 3). (Equation 1) For many forest species, the influence of levels of shading or types of protected environments on the formation of seedlings has already been researched; however, in the literature, there are few studies on how plant environment affects the formation of oiti seedlings (Licania tomentosa) and other species of the same family (Chrysobalanaceae). Some forest species have been assessed on cultiva- tion benches containing reflective material and obtained promising results regarding the use of supplementary radiation provided by the reflection of photosyntheti- cally active radiation (PAR). For jambolana (Syzygium cumini), reflective material on the cultivation bench inside a 30% shading screen promoted the best seed- lings (Salles et al. 2017). There was a positive effect on the quality of paricá (Schizolobium amazonicum) seedlings with a reflective material (aluminum foil) on cultivation benches inside an agricultural green- house with a 42%/50% shading screen under film (Mortate et al. 2019). The use of mirrors as reflective material on benches in cultivation provided better seedlings of baru (Dipteryx alata Vog.)(Costa et al. 2020a); however, the use of aluminized screen (Alu- minet®) did not increase their quality (da Costa et al. 2020). Seedlings of rubber tree rootstock (Hevea brasiliensis), clone GT1, showed a robust root sys- tem and better-quality seedlings on benches with Aluminet® reflective material (Costa et al. 2021). The present study aims to evaluate the formation of oiti seedlings in different protected environments with or without reflective material on a cultivation bench. MATERIALS AND METHODS The experiments were conducted from December 2019 to March 2020 at the State University of Mato Grosso do Sul (UEMS) in Cassilândia-MS, Brazil, at 19°07ʹ21ʺS, 51°43ʹ15ʺW and an altitude of 516 m (Cassilandia-A742 automatic station). The climate of the region is Aw-type, rainy in summer and dry in winter. Oiti seedlings were developed under protected environments with and without reflective material on the cultivation bench. The protected environments used, with a galvanized steel structure, were: (A1) agricultural greenhouse covered with low-density polyethylene (plastic screen) film (LDPE) with a screen of 42%/50% shading under the film; (A2) agricultural screenhouse with an aluminized screen ..... . ......... ................
July 2023
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