Tillage system and P fertilizer placement can aff ect plant root growth and therefore water and nutrient uptake. Th e objective of this study was to evaluate the eff ect of P fertilizer placement and tillage system on soybean [Glycine max (L.)] root growth and grain yield under induced drought stress. A fi eld study was performed at two locations in southern Brazil, during the 2014/2015 season. Phosphorus fertilizer placement and tillage combinations were evaluated using triple superphosphate at 31 kg P ha-1. Treatments included: (i) strip-tillage with deep band (ST-DB); (ii) strip-tillage with band-applied 5 by 5 cm (ST-B); (iii) no-till with broadcast (NT-BR); (iv) no-till with band-applied 5 by 5 cm (NT-B); and (v) no-till with surfaceband (NT-SB). Root length density (RLD) and root diameter were evaluated at 0-to 25-cm depth in 5-cm intervals. Yield was evaluated under rainfed as well as under induced drought conditions. Th e ST-DB treatment showed increased total RLD among treatments, with about 58% greater RLD than the NT-BR treatment, and 46% greater RLD than the NT-B treatment at the 15-to 25-cm soil depth. Furthermore, the soybean yield penalty with the ST-DB treatment was lower than any other treatment with a yield reduction of about 9 and 0.3% at respective locations under induced drought stress. Results from our study showed that the ST-DB treatment contributed to enhance soybean root growth at deeper soil layers and improved overall resilience to induced drought.

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This work aims at evaluate ethanol effect of acetaldehyde application in post-storage quality of 'Royal Gala' apples maintenance, and to compare them with consolidated storage techniques. Thus two experiments were performed during the years of 2008 and 2009. In the fi rst experiment (2008), the application of ethanol, acetaldehyde or 1-MCP and ethylene scrubbing were tested. Fruits were stored in controlled atmosphere (CA) with 1.0kPa O 2 and 2.0kPa CO 2 at 0.5°C. In the second experiment (2009), the treatments tested were ethanol application combined or not with low relative humidity (LRH) and LRH alone. In this experiment, apples were stored in CA with 1.2kPa O 2 + 2.5kPa CO 2 at 0.5°C. After eight months of storage, 0.5 mL ethanol kg -1 apples month -1 or 0.25 mL acetaldehyde kg -1 apples month -1 increased mealiness, fl esh browning, and decays incidence and reduced fl esh fi rmness. In contrast, 0.3 mL ethanol kg -1 apples month -1, tested on second experiment, prevented fruit softening and decreased ACC oxidase activity and ethylene production. Although lower relative humidity was not effi cient in maintaining poststorage quality, it enhanced the positive effect of ethanol application at 0.3 mL kg -1 apples month -1 .

Potato cultivation is widespread around the world, being exposed to several abiotic stresses, including soils with high aluminum (Al) availability. Silicon (Si) is recognized for alleviating the stress caused by Al in various plant species. Thus, the aim of this study was to investigate the potential of Si to mitigate the oxidative stress caused by Al in potato genotypes, exhibiting differential sensitivity toward this element. Plants of the Al-sensitive genotype (SMIJ319-7)and Al-tolerant genotype (SMIF212-3) were grown for two weeks in a hydroponic system with the nutrient solution containing combinations of Al (0 and 1.85 mM) and Si (0, 0.5 and 1.0 mM). At the end of the experiment, photosynthetic parameters, pigment content, root and shoot growth, superoxide dismutase and guaiacol peroxidase activity and lipid peroxidation were evaluated. In both potato genotypes Al BASIC AREAS -Article inhibited root and shoot growth and decreased all photosynthetic parameters and superoxide dismutase activity. Silicon was able to partially alleviate the damage caused by Al in parameters of root growth in the Al-tolerant genotype while increasing the activity of antioxidant enzymes and mitigating the Al-induced damage to membrane lipids in roots and shoot in both genotypes. The Al-tolerant genotype showed greater water use efficiency and transpiration rate in control conditions as compared to the Al-sensitive genotype. These data indicate that Si application can improve the defense ability of the tested potato genotypes against Al toxicity and that the Al-tolerant genotype is more responsive to Si.

O objetivo deste trabalho foi avaliar a perda da eficiência do controle do etileno com o uso de 1-MCP e da sua absorção ao longo do período de oito meses de armazenamento em atmosfera controlada (AC) de maçãs da cultivar 'Royal Gala' colhidas em estádio de maturação avançado. Os frutos foram colhidos com firmeza da polpa de 89,5N; índice de iodo-amido de 6,7; acidez de 5,06meq 100mL-1; teor de sólidos solúveis de 11,8°Brix; produção de etileno de 0,721µL C2H4 kg-1 h-1; e respiração de 6,61mL CO2 kg-1 h-1. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro tratamentos e seis repetições. Os frutos foram armazenados na temperatura de 0,5°C (±0,1), sendo avaliadas as seguintes condições: [1] AC com 1,2kPa O2 + 2,5kPa CO2; [2] AC com aplicação de 1µL L-1 de 1-MCP; [3] AC com aplicação de 1µL L-1 de 1-MCP e de 10µL L-1 de etileno (AE); e [4] AC com baixa concentração de etileno (<0,1µL L-1) (BE). O 1-MCP não apresentou eficiência na conservacão da firmeza da polpa em maçãs colhidas em estádio de maturação avançado, mas manteve eficiência na redução da atividade da enzima ACC oxidase, produção de etileno e atividade respiratória dos frutos.

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RESUMO Este trabalho teve como objetivo avaliar o efeito de diferentes números de aplicações de cloreto de cálcio (CaCl

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