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The aim of this study was to evaluate and explicate the changes in the nitrogen compounds and enzyme activities in Sorghum bicolor plants (cv. Br-700) submitted to water deficit during vegetative, reproductive and maturation stages. The experimental design used was entirely randomized in factorial scheme, with two conditions (control and stress) combined with three stages (vegetative, reproductive and maturation). The nitrate level was increased at 180.6, 72.9 and 78.9% during the vegetative, reproductive and maturation stages, respectively. The total soluble amino acids and glycinebetaine increased only during vegetative and reproductive stages, if compared with control plants. However, besides protein levels during all stages, significant reductions were reported in nitrate reductase and glutamine synthetase activities; free ammonium presented decreases at 37.3 and 77.6% in vegetative and reproductive stages, respectively, when compared with control plants.

This study investigated whether gas exchange and the present content of antioxidant compounds can contribute to the survival of Euterpe oleracea plants in environments of frequent waterlogging. A factorial randomised, experimental design included two distinct water conditions (waterlogging and control) and five evaluation times (0, 6, 12, 18, and 24 d). Gasexchange parameters, leaf temperature, electrolyte leakage, and contents of antioxidant compounds were measured. Waterlogging did not promote significant alterations in net photosynthetic rate and transpiration, and stomatal conductance was reduced only after 18 d. Malondialdehyde and glutathione contents did not significantly change during waterlogging. Additionally, electrolyte leakage was significant only after 18 d of waterlogging. Thus, this study revealed that maintenance in gas exchange and antioxidant compounds might contribute to the survival of E. oleracea plants in environments exposed to waterlogging.

Euterpe oleracea (Mart.), an Amazonian palm, is of economic importance due to the production of energy drinks. Plants exposed to waterlogging are prone to damage at the cellular level and cause irreversible metabolic dysfunctions leading to cell death. This study was aimed to study cell damages and to investigate enzyme activities related to antioxidant system in this specie. The experimental design was in factorial randomized with two water conditions (waterlogging and control) and five evaluation times (0, 6, 12, 18, and 24 days). The parameters measured were electrolyte leakage (EL), contents of hydrogen peroxide (H 2 O 2 ), malondialdehyde (MDA) and glutathione (GSH), and enzymatic activities of catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX) in leaf and root tissues. Waterlogging did not promote significant modifications in EL, MDA and H 2 O 2 in both the tissues evaluated, and a minor alteration in GSH was observed only in the roots. Significant increases in the activity of CAT, APX and POX were observed in leaf and roots, at early stages. It can thus be concluded that CAT, APX and POX were efficient in controlling EL and MDA in leaf and root of E. oleracea plants under waterlogging.

O controle químico não tem apresentado eficiência em determinadas regiões brasileiras, devido ao hábito de lagartas Spodoptera eridania permanecer na região inferior das folhas, dificultando que a molécula química atinja o alvo. Diante disso, o objetivo do trabalho foi verificar a eficiência do produto biológico a base de Bacillus thuringiensis no controle da lagarta Spodoptera eridania. O trabalho foi realizado na fazenda Água Boa localizada no município de Paragominas-PA. O delineamento experimental utilizado foi inteiramente casualizado, com 4 tratamentos e 4 repetições, os tratamentos foram: 1 - Testemunha; 2 -  Xentari + Klorpan  (biológico); 3 - Dimax + Klorpan; 4 - Prêmio + Brutos. Os parâmetros avaliados foram nível de largatas e controle, desfolha, fitotoxicidade, peso de mil grãos, umidade, custo x benefício e produtividade. Os dados foram submetidos à análise de variância (ANOVA) e comparados pelo teste de Tukey, a 5% de probabilidade. O Inseticida biológico à base Bacillus thuringiensis, Xentari + Klorpan proporcionou um maior controle de lagartas Spodoptera eridania, melhor produtividade e rendimentoda soja, no município de Paragominas. Destaca-se que esse inseticida biológico proporcionou benefícios tanto para o produtor, no que se refere à produtividade e lucro, como para o meio ambiente.