The present study evaluated the physiological and biochemical parameters of apple trees under different irrigation water depths in a semiarid region of Brazil. The experiment had a split-plot randomized block design. Irrigation levels (60, 80, 100, and 120% of the reference evapotranspiration - ET0) and two apple cultivars (Julieta and Princesa) were analysed in the experimental plots and the phenological stages (vegetative, flowering and fruiting) were analysed in the experimental subplots. The physiological characteristics evaluated included the chlorophyll index, relative water content, net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, leaf temperature and instant carboxylation efficiency. The biochemical characteristics evaluated included the leaf contents of reducing sugars, total soluble sugars, and non-reducing sugars and proteins. The best biochemical responses were observed in the Princesa cultivar under 80% ET0 during the flowering and vegetative stages and under 120% ET0 during the fruiting stage. The best physiological responses for all phenological stages were observed under irrigation levels of 120% ET0 for both cultivars. The cv. Princesa demonstrated osmotic adjustment under water stress conditions during the phenological stages evaluated.
Passiflora foetida, uma espécie de maracujá silvestre, tem sido pesquisado devido ao seu potencial farmacêutico e sua característica agronômica de resistência ao Fusarium spp., possibilitando a sua utilização como porta-enxerto para espécies de maracujá suscetíveis a morte prematura. Assim, visando a propagação dessa espécie, a micropropagação é uma das formas mais utilizadas, sendo necessário a utilização de acessos de uma planta matriz para, por organogênese, gerar novas plântulas com o mesmo genótipo. Desta forma, este trabalho teve como objetivo estabelecer protocolo para a propagação in vitro de P. foetida pela indução de gemas por organogênese, testando-se duas concentrações de sais minerais do meio MS, sem adição de fitormônios. Para o estabelecimento in vitro foram utilizados gemas apicais e laterais obtidas a partir de plantas matrizes de P. foetida, cultivadas em casa de vegetação. Os experimentos foram realizados em delineamento inteiramente casualizado. Aos 60 dias após a inoculação dos explantes foram avaliados: número de gemas, comprimento da brotação, número de folhas, escore de coloração, escore de desenvolvimento e número de raiz. Para garantir a precisão dos resultados foram realizadas técnicas estatísticas aplicadas à análise de dados e otimização dos resultados. O desenvolvimento das plantas por organogênese apresentou valores estatisticamente similares em ambas as concentrações, podendo concluir que o meio MS com metade das concentrações de nutrientes foi o mais viável para o estabelecimento in vitro dessa espécie.
-The great solar radiation in the Brazilian semiarid region, combined with an adequate irrigation management, favors fruit production and quality of crops that were adapted to this region. The objective of this work was to evaluate the fruit quality of two apple cultivars grown in the Sub-Mid São Francisco River Valley under different irrigation water depths. A complete randomized block experimental design in a split-plot arrangement with five replications was used. The plots consisted of four irrigation water depths (ID) (60, 80, 100 and 120% of the reference evapotranspiration -ETo), the subplots consisted of two apple cultivars (C) (Julieta and Princesa) and the sub-subplots consisted of fruit positions in the tree canopies (FP) (east and west sides). The soluble solids content (SS), titratable acidity (TA), SS/TA ratio, pulp firmness (PF) and fresh weight (FW) of the fruits were evaluated. The factors evaluated showed no triple interaction between the evaluated factors, however, the SS and TA were significantly affected by them; the interaction between ID and C significantly affected the PF; the interaction between ID and FP significantly affected the PF, SS/TA ratio and FW; and the interaction between C and FP significantly affected the SS/TA ratio. The increase in water depth increased the fruit size of both cultivars, without compromising the post-harvest quality. The cultivar Princesa presented the best results regarding SS, TA, PF and FW, however, both cultivars had organoleptic characteristics within the recommended standards for commercialization. The fruits harvested on the west side presented better post-harvest quality.Keywords: Water regimen. Malus domestica Borkh. Post-harvest. QUALIDADE DOS FRUTOS DE MACIEIRAS IRRIGADAS NO SEMIÁRIDO NORDESTINORESUMO -A elevada radiação associada ao manejo adequado da irrigação no semiárido brasileiro favorece o aumento da produção e a qualidade dos frutos de culturas adaptadas a região. O objetivo deste trabalho foi avaliar a qualidade dos frutos de duas variedades de maçãs cultivadas na região do Vale Submédio do Rio São Francisco sobre diferentes lâminas de irrigação. O delineamento experimental foi em blocos ao acaso, com parcelas subsubdivididas, com cinco repetições, sendo as parcelas principais quatro lâminas de irrigação (60; 80; 100; e 120 % da evapotranspiração de referência -ETo), as subparcelas duas cultivares de maçã (Julieta e Princesa) e as subsubparcelas as posições da copa da planta (leste e oeste). Avaliou-se o teor de sólidos solúveis (SS), a acidez titulável (AT), a relação entre SS/AT, a firmeza de polpa (FP) e a massa de matéria fresca do fruto (MMFF). Não se observou interação tripla entre os fatores avaliados, mas houve um efeito significativo das características SS e AT, da interação entre lâminas e cultivares para FP, da interação entre lâminas e posição para FP, razão de SS/AT e MMFF e da interação entre cultivares e posição para relação SS/AT. O aumento da irrigação promoveu aumento do tamanho dos frutos, das duas cultivares, ...
Knowledge of the physiological mechanisms in saline environment may boost sugarcane breeding programmes targeting abiotic stresses. Our hypothesis is that the physiology of Saccharum genotypes responds differently under salt stress. Thus, the objective of the study was to evaluate the physiological performance of Saccharum complex genotypes grown under presence and absence of saline stress. The experimental design used was randomized blocks arranged in a 32 × 2 factorial scheme (32 genotypes × 2 salinity levels). The presence of salinity provided higher mean values for photosynthetic rate in genotypes G4, G18, G22, G25 and G29 compared with the environment without salinity, with mean values (17.26, 21.49, 24.22 and 26.19 µmol CO2m−2s−1), respectively, for internal CO2 concentration in G2, G6, G9, G14, G17, G19, G23 and G29, with mean values (323.45, 399.64, 386.88, 412.14, 366.31, 250.48, 379.10 and 380.75 µmol CO2 mol air−1), respectively, for transpiration in G18, G24, G25 and G29, with mean values (5.05, 3.30, 4.39 and 4.01 mmol H2O m−2s−1), respectively, and for chlorophyll content in G3, G5, G6, G8, G10, G13, G20, G22, G23, G25, G31 and G32, with mean values (34.18, 43.01, 38.08, 32.38, 37.09, 37.18, 32.47, 38.38, 38.04, 36.95 and 33.32 SPAD units) respectively. Genotypes that under salt stress increase their physiological performance demonstrate superiority over others and should be considered in breeding programmes. Photosynthesis and transpiration is the most adequate combination for screening, but the spad index is the most viable tool because of its ease of determination and cost.
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