ABSTRACT 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.

RESUMO O uso de resíduo orgânico no substrato e a disponibilidade de luz influenciam na obtenção de mudas de elevada qualidade para o cultivo ex situ de espécies florestais nativas. Objetivou-se com este estudo avaliar o efeito de doses de cama de frango incorporadas ao solo e níveis de sombreamento sobre as respostas morfofisiológicas e qualidade de mudas de Alibertia edulis (Rich.) A. Rich. Foram estudadas cinco doses de cama de frango (CF): 0,00; 2,08; 4,16; 6,24 e 8,32 g kg-1 sob duas condições de sombreamento: 0% (pleno sol) e 50% de sombreamento. Aos 215 dias após o transplantio, a máxima altura da A. edulis foi 47,35 cm com 5,64 g CF kg-1 solo sob 50% de sombreamento. Mudas sombreadas tiveram maior número de folhas. A máxima área foliar e radicular foi de 796,64 e 118,83 cm2 com 5,32 g e 4,21 g CF kg-1 solo, respectivamente, ambos sob 50% de sombra. Mudas sob 0% de sombra tiveram menores índices fisiológicos. Os níveis de sombreamento não afetaram a limitação estomática, mas a CF contribuiu na eficiência fisiológica. As biomassas da parte aérea foram maiores sob 50% de sombra com maiores doses de CF. Os maiores índices de qualidade ocorreram com 3,98 e 6,28 g CF kg-1 solo sob 0 e 50% de sombra, respectivamente. Mudas de A. edulis responderam positivamente à adição de CF ao solo e apresentaram plasticidade às condições contrastantes de luz. Mudas de A. edulis produzidas em 50% de sombra com adição de 6,24 g CF kg-1 solo apresentaram maiores indicadores morfofisiológicos e qualidade de mudas. A adição de 4,32 g CF kg-1 solo contribuiu na qualidade de mudas sob pleno sol.

ABSTRACT 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.

RESUMO O alagamento é um fator estressante e promove danos ao aparato fotossintético, afetando negativamente o crescimento de mudas de espécies frutíferas, dentre elas a jatobazeiro Estudos sobre o manejo fisiológico, tal como aplicação exógena de fitohormônio, para aliviar o estresse abiótico tem aumentado. Assim, objetivou-se com esse estudo avaliar o efeito da aplicação foliar de concentrações de ácido salicílico (AS) em mudas de H. courbaril submetidas ao alagamento. As mudas receberam aplicação via foliar de quatro concentrações de AS: 0, 100, 200 e 400 mg L-1, e submetidas a dois regimes hídricos: a) controle: - não alagadas e irrigadas diariamente e b) alagamento - acondicionamento das mudas em piscina com lâmina d’água (5.0 cm) acima do nível do substrato. Decorridos 35 dias avaliamos as trocas gasosas, crescimento inicial, qualidade e o potencial de resiliência ecológica das mudas. Observou-se que todas as mudas alagadas sobreviveram, mas tiveram redução da fotossíntese, eficiência instantânea de carboxilação da Rubisco e de uso da água e condutância estomática e quando receberam aplicação entre 100-300 mg L-1 de AS. As mudas que receberam aplicação das concentrações entre 100 e 300 mg L-1 de AS tiveram maiores características de crescimento, qualidade e plasticidade fenotípica. A aplicação foliar de ácido salicílico não mitigou o efeito do alagamento sobre as trocas gasosas, mas contribuiu no crescimento das mudas de H. courbaril.

RESUMO O manejo fisiológico e nutricional é uma prática importante para obtenção de mudas de alta qualidade e o uso de extrato de algas tem se tornado uma alternativa aos fertilizantes e bioestimulantes, mas informações para Alibertia edulis, uma espécie frutífera e nativa do Cerrado, são escassas. Objetivou-se com este trabalho avaliar o efeito de doses do extrato de alga Ascophyllum nodosum L. (ANE), associadas ou não ao nitrogênio mineral no crescimento, índices de eficiência do nutriente nitrogênio e na qualidade de mudas de A. edulis. As mudas receberam aplicação de cinco doses de ANE (0, 5, 10, 15 e 20 mL L-1 de água) via foliar, sem e com adição de N mineral (50 mg kg-1 de ureia ao solo). O delineamento utilizado foi o de blocos casualizados, e os tratamentos foram arranjados em esquema fatorial 5 × 2. Os dados de altura, diâmetro do coleto, número de folhas e o índice de clorofila ao longo do tempo foram analisados em parcelas subdivididas no tempo. A aplicação foliar do extrato de A. nodosum nas doses de 15 e 20 mL L-1, contribuiu para maiores características de crescimento e qualidade de mudas, independente do uso de nitrogênio mineral. Mudas com N mineral e com 13,98 mL L-1 de ANE tiveram maior área foliar. A maior eficiência e absorção de N e uso de nutrientes ocorreu nas mudas que receberam o extrato de alga A. nodosum.

ABSTRACT Physiological and nutritional management is an important practice for obtaining high quality seedlings. The use of seaweed extract has emerged as an alternative to fertilizers and biostimulants, although information on this with respect to Alibertia edulis, a fruit-bearing species native to the Cerrado region, is scarce. The aim of this study was to evaluate the effects of the Ascophyllum nodosum L. seaweed extract (ANE), both with and without the addition of mineral nitrogen, on the growth, nitrogen nutrient efficiency indices, and quality of A. edulis seedlings. The seedlings received five doses of ANE (0, 5, 10, 15, and 20 mL L-1 of water) via foliar application, with and without the addition of mineral N to the soil (50 mg kg-1 of urea). A randomized block design was used with the treatments arranged in a 5 × 2 factorial scheme. The plant height, stem diameter, chlorophyll index, and number of leaves obtained were analyzed in split-plots over time. Foliar application of 15 and 20 mL L-1 of ANE contributed to greater growth and seedling quality, regardless of the addition of mineral nitrogen. Seedlings treated with mineral N alongside 13.98 mL L-1 of ANE showed the greatest leaf area. The highest N use efficiency, N uptake, and nutrient use occurred in seedlings that received A. nodosum extract.

RESUMO O déficit hídrico afeta negativamente a síntese de pigmentos fotossintéticos, os processos fotoquímicos da fotossíntese e a qualidade das mudas. Supõe-se que a aplicação exógena foliar de ácido salicílico (AS) pode contribuir na regulação fotoquímica e aumenta a tolerância ao estresse. Objetivou-se avaliar o efeito do AS em aliviar o efeito estressante do déficit hídrico sobre as atividades fotoquímicas da fotossíntese e qualidade das mudas de Schinus terebinthifolia Raddi. As mudas foram submetidas a quatro regimes hídricos: 0, 4, 8 e 12 dias de restrição hídrica (DRH), associadas a quatro concentrações de AS: 0, 50, 100 e 200 mg L-1 (via pulverização foliar; 10 mL por planta) durante 48 dias. O crescimento de S. terebinthifolia é afetado negativamente por maiores dias de restrição hídrica e sem tratamento de AS. Entretanto, a aplicação de 200 mg L-1 de SA incrementou os pigmentos fotossintéticos, além da eficiência quântica fotoquímica no fotossistema II e de conversão de energia absorvida nas mudas sob 12 DRH. A qualidade das mudas foi maior aos 7 e 12 DRH com aplicação de 100 e 200 mg L-1 de SA, respectivamente. A aplicação exógena de AS contribuiu positivamente nas concentrações de pigmentos, estabilidade fotoquímica da fotossíntese e qualidade das mudas de S. terebinthifolia submetidas à maiores períodos de restrição hídrica.

ABSTRACT Water deficit adversely affects photosynthetic pigment synthesis, photochemical processes, and seedling quality. Exogenous foliar application of salicylic acid (SA) is hypothesized to contribute to photochemical regulation and increase stress tolerance. This study aimed to evaluate the effect of SA in alleviating the effects of water deficit stress on the photosynthetic photochemical activities and quality of Schinus terebinthifolia Raddi. seedlings. The seedlings were subjected to four regimes of water deficit: 0, 4, 8, and 12 days of water restriction (DWR), associated with the application of four concentrations of SA: 0, 50, 100, and 200 mg L-1 (via foliar spray; 10 mL per plant) during 48 days. Growth of S. terebinthifolia seedlings was adversely affected by longer duration of water restriction in absence of SA treatment. However, application of 200 mg L-1 of SA increased photosynthetic pigment levels, photochemical quantum efficiency in photosystem II, and absorbed energy conversion efficiency in seedlings under 12 DWR. The seedling quality was better at 7 and 12 DWR when associated with application of 100 and 200 mg L-1 SA, respectively. The exogenous application of SA contributed positively to pigment concentration and photochemical stability of photosynthesis, and it improved the quality of S. terebinthifolia seedlings subjected to long water restriction periods.

ABSTRACT Water availability is one of the most important factors for the growth of tree seedlings in forestry-related regions. We hypothesized that under different water regimes, a water-retaining polymer (hydrogel) can positively contribute to chlorophyll- a fluorescence and growth in Campomanesia xanthocarpa (Mart.) O. Berg. Four water retention capacities (WRC) were evaluated: 25%, 50%, 75%, and 100%, depending on the presence or absence of hydrogel at the substrate. The lowest WRCs, particularly those under 25% without hydrogel, reduced chlorophyll index and negatively affected the photochemical activities of photosystem II. However, under low water availability the hydrogel mitigated the damage inflicted on the reaction centers and chlorophyll synthesis. The greatest growth effects occurred at 100% WRC in the presence of the hydrogel. Physiological indices were higher under 100% WRC without hydrogel and 50% with hydrogel. The increase in biomass and Dickson quality were more pronounced in the seedlings produced under 50% WRC and hydrogel, and the addition of these parameters to the substrate contributed to more viable morphophysiological indicators for the production of C. xanthocarpa seedlings.

ABSTRACT The use of water-retaining polymer (hydrogel) can mitigate the damage to the photosynthetic apparatus and increase the robustness of young plants under water deficit conditions. Thus, the aim of this study was to evaluate the effect of water-retaining polymer on the morphophysiological aspects of Schinus terebinthifolia Raddi submitted to water deficit. The studied water regimes were characterized by three plant irrigation management: 1) control: irrigated daily, 2) stress: water deficit (irrigation suspension) and 3) stress + hydrogel: water deficit + water-retaining polymer. The plants were submitted to irrigation suspension until photosynthesis approached zero [1st P0], followed by resumption of irrigation (REI) for 15 days. After REI, until recovery of photosynthetic rate of plants, the maintenance of irrigation of all plants for 90 days, characterizing the final recovery (125th day of experiment). The photosynthetic rate reached values close to zero in plants under stress on the 20th day of water restriction, whereas the plants in conditions with hydrogel did not show a decrease in leaf metabolism. Excluding intercellular CO2 concentration, physiological parameters were lower on 1st P0 in plants under water deficit grown without hydrogel than those in plants grown with hydrogel, but all plants showed physiological plasticity. The use hydrogel contributed to the maintenance of the photosynthetic capacity of S. terebinthifolia under water deficit.

ABSTRACT Information on the physiological responses of native plants from the Brazilian Cerrado regarding the use of chicken manure and luminosities are important for their silvicultural management. Thus, aimed to evaluate the effect of chicken manure and luminous availability on the photosynthetic metabolism of Alibertia edulis (Rich) A. Rich. The experiment was carried out in pots, testing five doses of chicken manure – CM (0.00, 2.08, 4.16, 6.24 and 8.32 g kg-1) incorporated at Dystroferric Red Latosol, and two luminous environmental (full sun and 50% shaded). The higher CO2 assimilation rate, stomatal conductance and carboxylation efficiency of Rubisco occurred in seedlings grown in full sun. The seedlings showed higher photochemical indicators in photosystem II in the shaded and with addition of 8.32 g kg-1 of CM. The intercellular CO2 concentration in leaves was lower with addition of 5.55 g kg-1 of CM. The leaves presented larger stomatal dimensions under shaded. The cultivation of A. edulis in full sun and the addition of about 4.16 g kg-1 of CM favored greater stomatal regulation and CO2 assimilation.