Organic residue in the substrate and the availability of light influence the production of high-quality seedlings for ex situ cultivation of native forest species. This study aimed to evaluate the effect of doses of chicken manure incorporated in the soil and shading levels on the morphophysiological responses and quality of Alibertia edulis (Rich.) A. Rich seedlings. Five doses of chicken manure (CM) were tested, 0.00, 2.08, 4.16, 6.24, and 8.32 g CM kg-1 soil, under two shade conditions, 0% (full sun) and 50% shading. At 215 days after transplanting, the maximum height obtained for A. edulis was 47.35 cm with 5.64 g CM kg-1 soil under 50% shade. Shaded seedlings had a higher number of leaves. The maximum leaf and root areas were 796.64 and 118.83 cm2 with 5.32 and 4.21 g CM kg-1 soil, respectively, both under 50% shade. Seedlings in 0% shade had lower physiological indices. Shading levels did not affect stomatal limitation, but CM contributed to physiological efficiency. Shoot biomass was higher under 50% shade with higher CM doses. The highest quality indexes occurred with 3.98 and 6.28 g kg-1 CM under 0 and 50% shade, respectively. A. edulis seedlings responded positively to the addition of CM to the soil and presented plasticity under contrasting light conditions. A. edulis seedlings produced under 50% shading with the addition of 6.24 g CM kg-1 soil presented high morphophysiological and seedling quality indicators. The addition of 4.32 g CM kg-1 soil contributed to high seedling quality under full sun conditions.

Flooding is a stressful condition that causes damage to the photosynthetic apparatus, negatively affecting the growth of seedlings of fruit species, including Hymenaea courbaril L. Studies on physiological management, such as exogenous application of phytohormones, to alleviate abiotic stress have increased. The objective of this study was to evaluate the effect of foliar application of salicylic acid (SA) on H. courbaril seedlings subjected to flooding. The seedlings received foliar application of four concentrations of SA (0, 100, 200, and 400 mg L-1) and were subjected to two water regimes: a) control - non-flooded and irrigated daily and b) flooded - seedlings were placed in a plastic pool, keeping the water depth at ± 5.0 cm above the substrate level. After 35 days, we evaluated the gas exchange, initial growth, quality, and potential ecological resilience of the seedlings. All flooded seedlings survived, but had reduced photosynthesis, carboxylation of Rubisco efficiency, and water-use and stomatal conductance when they received 100-300 mg L-1 SA. The seedlings that received between 100 and 300 mg L-1 SA had greater growth, quality, and phenotypic plasticity. Foliar application of SA did not mitigated the effect of flooding on gas exchange but contributed to the growth of H. courbaril seedlings.

1. INTRODUCTION AND OBJECTIVES

Campomanesia adamantium (guavira), é frutífera nativa do Cerrado, encontrada em grande maioria no estado silvestre e apresenta limitações na propagação relacionada à recalcitrância das sementes. Considerando a ausência de manejo e tratos culturais, o estabelecimento da cultura in vitro a partir de material vegetativo está sujeito a altos índices de contaminação fúngica e bacteriana. Visando a propagação, objetivou-se avaliar a capacidade de multiplicação in vitro de guavira, utilizando segmentos caulinares retirados de plântulas da germinação in vitro. Foram desenvolvidos três experimentos, sendo avaliados o efeito de 5,0 µM de TDZ (thiadizurom), 1,0 µM de ANA (ácido naftaleno acético) e a combinação dos mesmos, bem como, o efeito isolado de BAP (6-benzilaminopurina) e 2iP (2-isopentenil adenina), nas concentrações de 0; 2,5; 5,0; 7,5 e 10 mg L-1. Os resultados obtidos demonstraram que o uso de 5,0 µM de TDZ aumentou o comprimento das brotações, número de gemas e taxa de multiplicação, enquanto a combinação de TDZ e ANA exerceu um efeito negativo sobre o crescimento das brotações, número de folhas e taxa de multiplicação. O cultivo dos explantes em meio contendo BAP aumentou o número de brotações, ao aumento da concentração do regulador, entretanto, reduziu o comprimento das brotações.

Microalgae have emerged as a promising renewable resource due to their biomass production and cell composition. This study aimed to evaluate a commercial nutrient source for Desmodesmus abundans L2B Bold cultivation, analyzing its metabolome, photosynthetic pigments, and biomass potential as a biostimulant for soybean crops. Samples underwent metabolomics analysis via GC/MS after derivatization. Microalgal biomass produced in a commercial fertilizer medium (CF) was applied as a biostimulant at three concentrations in soybean crops at 30, 50, and 70 days post-sowing. Pigments and dry biomass levels were similar in BG11 and CF media, but CF reduced production costs by 31.8%. Distinct metabolite profiles were observed, with major classes being organic acids (19%), amines (14%), sugars (12%), fatty acids (11%), and esters (10%). Foliar application of 20% (v/v) D. abundans L2B Bold increased stem diameter (5.88 mm), leaf fresh and dry mass, and stem mass. Additionally, there were increases in nitrogen (26%) and protein (38.1%) in seeds, alongside higher pod (10.9) and seed numbers (25.2) and seed mass (3.43 g) per plant⁻¹. These findings demonstrate the feasibility of using CF as a culture medium and the potential of D. abundans L2B Bold as a biostimulant for soybean production.