Amaranthus cruentus L. is a forage species, with grains that exhibit excellent nutritional characteristics, being the 'BRS Alegria' the first cultivar recommended for cultivation in Brazil. This study aimed at evaluating the effect of salt stress on the growth and concentrations of organic and inorganic solutes in Amaranthus cruentus L. ('BRS Alegria' cultivar). Height, stem diameter, number of leaves, leaf, stem and root dry mass, leaf area, relative water content and membrane integrity percentage, as well as soluble carbohydrate, free amino acid, soluble protein, free proline, Na+, Cl- and K+ contents, were evaluated in different plant organs. Salinity significantly reduced the biomass yield and leaf area from the treatment with 25 mM of NaCl, indicating that the 'BRS Alegria' cultivar is sensitive to salt stress. Soluble carbohydrates in the leaves decreased by 59 %, while the other organic solutes showed no substantial increases. These results, coupled with the reduction in the relative water content and membrane integrity, suggest a low ability of this cultivar to adjust osmotically under salt stress. The K+/Na+ ratio abruptly decreased in 25 mM of NaCl, suggesting an ionic imbalance, which may partially explain the salt-induced growth reduction.

Effect of interactions between ammonium and nitrate on the growth physiology of groundnutPeanut is a crop of great importance for the Northeast region, as it is usually grown by small farmers, who on average, do not exceed 10 ha of cultivated area and aim to increase its profitability and diversify the production. This study aimed to evaluate the effect of the relationship between nitrogen forms (ammonium and nitrate) in the initial growth of peanuts. Complete nutrient solution was used with a single concentration of 210 mg N L -1 provided in five proportions of NH 4 + :NO 3 -: 100:0, 75:25, 50:50, 25:75 and 0:100. The experimental units were arranged in completely randomized design, with four replications. The variables evaluated were: shoot length, root length, leaf number, stem diameter, fresh and dry shoot and fresh weight and dry root. The 100:0, 75:25 and 50:50 ratio resulted in decreasing peanut phytomass by ammonium toxicity. However, the 0:100 ratio, nitrate caused a smaller decreased compared to reductions in the highest ammonium concentrations. In the 25:75 and 0:100 ratio, plants grow normally with higher phytomass. The supply of nitrogen in the NH 4 + form only is not a good option for the nutrition of peanuts in early growth stages.

The aim of this study was to evaluate the effect of salt stress on the contents of inorganic and organic solutes, pigments and essential oil in two basil genotypes cultivated in hydroponic system. The experiment was carried out in a greenhouse. Treatments were distributed in randomized blocks, in a 2 × 2 factorial arrangement, corresponding to two contrasting genotypes (‘Toscano folha de alface’ (TFA) and ‘Gennaro de menta’ (GM)) and two salt levels (0 - control and 80 mM NaCl), with six replicates. The Na+, Cl- and K+ accumulation in the leaves, stem and roots did not differ between genotypes. Salt stress increased free amino acids accumulation in the leaves of the TFA genotype. The proline content increased in the roots of both genotypes. However, in GM genotype, the proline content (3.12 mmol g-1 dry mass (DM)) was around 2-fold greater when compared to TFA genotype (1.48 mmol g-1 DM). The salt stress increased the photosynthetic pigments content only in the GM genotype. Inorganic solutes and photosynthetic pigments content are not good indicators of salt-tolerance in the studied genotypes. Under salt stress, there was increase in oil content in GM genotype, while the TFA genotype showed a decrease compared to control treatment. In spite of showing lower oil content, the TFA genotype showed higher yield and productivity of essential oil compared to GM under salt stress conditions.

No abstract

No abstract