Corn (Zea mays L.) is highly adaptable, but it has difficulties in expressing its productive potential in soils with high aluminum content, since this element is directly related to high acidity in the soil. The objective of this study was to evaluate the nitrogen compounds, proteins and amino acids of two corn cultivars subjected to increasing doses of aluminum. The experiment was carried out in a greenhouse using one of the corn plants from varieties BRS 106 and BRS 4157. The experimental design was entirely randomized, in a factorial design of 5x2, and the factors were composed of five doses of Al 3+ (0; 50; 100; 150 and 200 mmol L-1), with five repetitions. The variables analyzed were the concentration of nitrate, the activity of the nitrate reductase, concentration of ammonium, amino acids and proteins. There was a decrease in nitrate, activity of the Reductase enzyme of the Nitrate and protein in the highest dose of aluminum (200 mmol L-1) for both cultivars. There was an increase in ammonium and amino acids in the leaves of cultivars BRS 106 and BRS 4157. Cultivars BRS 106 and BRS 4157 were affected by the increasing doses of aluminum, but cultivar BRS 106 showed to be more tolerant.

species, colonizer of marginal lands and road margins, which often initiates secondary succession in open areas by the intense germination of their seeds in the soil. Studies on fastgrowing Amazon forest species are very scarce, when it refers to the influence of abiotic factors on an ecophysiology of the species. The experiment was conducted in a greenhouse belong to laboratory of Estudos da Biodiversidade de Plantas Superiores of the Federal Rural University of Amazonia. The experiment was completely randomized in split plot scheme, two times: five and ten days of water suspension, and two water conditions: control and water deficit, with four replications with one plant /pot. The water deficiency condition for ten days negatively affected the growth and indicators of gas exchange (A, gs and E). Adding to the fact that the experiment occurred in a year of extreme climatic anomaly (El Niño), the plants did not resist and perished in the internal conditions of greenhouse. The water deficiency condition altered the growth parameters and the environmental relations of the Tachigali vulgaris species, thus evidencing its low physiological plasticity to this abiotic condition.

We aimed to evaluate the changes in biochemical metabolism generated by salt stress and to investigate the effect of brassinosteroids in mitigating of this stress on two cultivars of Vigna unguiculata L. We used a completely randomized experimental design in a 2 x 3 x 3 factorial scheme, using two cultivars of cowpea (BRS Guariba and BR3 Tracuateua - moderately tolerant and sensitive to salinity, respectively), three concentrations of brassinosteroids (0, 0.2 and 0.4 μM Br) and three concentrations of NaCl (0 , 50 and 100 mM NaCl), with four replicates. The following evaluations were carried out: relative water content, electrolyte leakage, nitrate levels, nitrate reductase activity, free ammonium, total soluble amino acids, soluble proteins, glycine betaine and proline. The results showed that salinity at 100 mM affected the nitrate reductase enzyme activity, the relative water content, total soluble amino acids and soluble proteins for cultivars BR3 Tracuateua, and BRS Guariba, but the 24-epibrassinolid attenuated the effects of salinity for these variables. The concentration of 0.2 μM of Br increased 55% and 20% in proline and glycine betaine contents, respectively, in both of cultivars. The plants under stress saline and 0.2 mM of 24-epibrassinolid, presented 42% and 58% reductions in electrolyte leakage of BR3 Tracuateua and BRS Guariba cultivars, respectively. The concentrations of ammonium were slightly varied. Therefore, the application of 0.2 μM of 24-epibrassinolid caused a greater acclimatization of the cultivars, being the BR3 Tracuateua (sensitive to salt) cultivar more expressive in most treatments.

Espécimes de Pectis elongata Kunth apresentam variações de aromas quando maceradas, alguns acessos apresentam aroma de cominho(PCH), enquanto outros apresentam aroma de capim-santo(PCS). O objetivo deste trabalho foi avaliar as variações morfoanatômicas dentre esses espécimes e caracterizá-los nesses aspectos. A partir de material fértil com mesmo nível de desenvolvimento, foram feitos registros morfológicos com desenhos à Nankin, seguindo as técnicas usuais na composição de pranchas para fins taxonômicos. As fotomicrografias em microscopia fotônica foram obtidas a partir de lâminas histológicas dos órgãos vegetativos caule e folha, confeccionadas a mão livre, seguindo as técnicas usuais da anatomia vegetal. Os espécimes PCH apresentaram estrutura caulinar com seis lados bem destacados, entrenós mais alongados e com poucas ramificações; folhas mais desenvolvidas e com menor quantidade de emergências na margem; nó com menor quantidade de estípulas quando comparados com amostra de PCS, cujo caule apresentam entrenós mais curtos, amplamente ramificado; folhas menores com até quatro emergências na base foliar e nó com quatro estípulas. As folhas são anfiestomáticas, com estômatos anisocíticos em ambos espécimes, mesofilo dorsiventral e presença de bainha Kranz contornando os feixes vasculares e cavidades secretoras são mais destacadas nos espécimes PCS. A caracterização em nível morfológico e anatômico ratificam outras publicações no gênero Pectis. As variações morfoanatômicas são perceptíveis, entretanto não são suficientemente diagnósticas para afirmarmos tratar-se de espécies diferentes, mas há forte indício de constituírem diferentes quimiotipos.

The propagation of S. amazonicum by seeds can result in uneven seedlings that are subject to poor quality, which is detrimental to uniformity and productivity. The absence of an efficient method of vegetative propagation of the species may be a limitation for genetic improvement, and consequently the increase in productivity of plantation. This study aimed to evaluate the effect of indole-3-butyric acid (IBA) in the rooting of cuttings of paricá -Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby. The cuttings obtained from the stems of the seedlings then were treated with IBA in the hydro-alcoholic solutions at 1000, 2000, 3000 and 4000 ppm; commercial product with 2000 ppm IBA powder; commercial product composed of IBA and nutrients; and treatment control (0 ppm). The cuttings were planted in plastic trays with vermiculite and coconut fiber (1:1 v/v) and placed in a box lined with plastic to control moisture. The experimental design was completely randomized with five replications and 10 cuttings per plot. After 60 days, the percentage of rooted cuttings, living and dead, and number and length of roots were analyzed. The analysis of variance at 5% of probability indicated statistical differences for all variables. The best results were observed when we used IBA at 2000 and 3000 ppm, diluted in hydro-alcoholic solutions. These treatments showed statistically equal and produced the highest percentage of rooting, average number and length of roots and lowest percentage of dead cuttings. The polynomial regression analysis indicated that higher rooting rates can be obtained in 2550 ppm of IBA diluted in hydro-alcoholic solutions.Keywords: auxin, adventitious roots, fabaceae, vegetative propagation. Abbreviations: IBA_indole-3-butyric acid; PPM_ part per million; RC_Percentage of rooted cuttings; NMR_Average root number per stem; LLR_Length of the largest root; LC_Percentage of live cuttings; DC_Percentage of dead cuttings.

Oil palm is a very responsive culture in relation to climate change that intensifies or lowers its productivity. Thus, the objective of this study is to evaluate the activity of antioxidant enzymes in two genotypes of E. guineensis, both under water deficiency. The experiment conducted in a greenhouse at UFRA used genotypes 2528 and 2501 of E. guineensis submitted to water deficiency from the 10 th day. The biochemical analysis was evaluated at the 5% level of significance by the Tukey test. The antioxidant variables analyzed were superoxide dismutase, catalase activity, ascorbate peroxidase activity, Malondialdeído (MDA), Glutathione and ascorbic acid content. In view of the obtained results, it was observed increases of the antioxidant enzymes when the genotypes were submitted to the water deficiency, presented significance for the results. Therefore, the study suggests that oil palm had a good use and adaptation when submitted to water deficit and that genotype 2528 was more responsive to maintain its vital biochemical activities.

Cowpea (Vigna unguiculata (L.) Walp.) is a legume widely cultivated by small, medium and large producers in several Brazilian regions. However, one of the concerns for the production of cowpea in Brazil in recent years is the low rainfall activity in these regions, which generates the accumulation of salts on the surface. The objective of this work was to evaluate the effects of salt stress on growth parameters and enzyme activity in cowpea plants at different concentrations of brassinosteroids. Experiment was developed in a greenhouse using a completely randomized experimental design in a 3 x 3 factorial scheme. The treatments consisted of three levels of brassinosteroids (0, 3 and 6 µM EBL) and three levels of salt stress (0, 50 and 100 mM NaCl). Growth factors (height, diameter and number of leaves) decreased in the saline condition. With the presence of brassinosteroid the height did not increase, but the number of leaves did, mainly in the saline dosage of 100 mM NaCl. In the variable membrane integrity, brassinosteroid was efficient in both salinity dosages, the same not happening with the relative water content, where the saline condition did not affect the amount of water in the vegetable, with the application of brassino it remained high, decreasing only at dosage 100 mM NaCl. The nitrate reductase enzyme was greatly affected in the root system even with the application of increasing doses of brassino. Therefore, brassinosteroids as a promoter of saline tolerance in cowpea seedlings was positive. The concentration of 3µM of EBL provided the most satisfactory effect in tolerating the deleterious effects of the saline condition. The same cannot be concluded for the concentration of 6µM of EBL that did not promote tolerance to some variables.

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