Caio César Pereira Leal

Produção e qualidade de sementes de feijão-caupi em função de sistemas de plantio e estresse hídrico

The cowpea plays an important role in the Brazilian agricultural production, especially in the North and Northeast Regions, where it is widely cultivated by smallholders. Thus, this study aimed at evaluating the physiological quality of cowpea seeds produced under no-tillage and conventional tillage and different periods without irrigation. A randomized blocks design, in a split-plot scheme, with four replications, was used. The plots consisted of cropping systems (no-tillage and conventional tillage), while the subplots consisted of periods without irrigation (2, 6, 10, 14, 18 and 22 days). In the plots, seeds were collected and subjected to the following evaluations: seeds weight per plant, one thousand seeds weight, test weight, seed length and width, moisture content, germination, accelerated aging, field seedling emergence and emergence speed index. Cowpea seeds from plants subjected to hydric stress resulted in lower physiological quality, but were physically bigger and heavier. The no-tillage system provided seeds with better physiological quality. Cowpea plants subjected to hydric stress after flowering produced fewer seeds.

Efeito da salinidade na emergência e crescimento inicial de plântulas de flamboyant

The objective of this study was to evaluate the effect of different salt concentrations in irrigation water on the emergence and initial development of flamboyant (Delonix regia (Bojer ex Hook.) Raf.) seedlings. The experiment was conducted in the greenhouse of the Department of Plant Sciences, Universidade Federal Rural do Semiarido - UFERSA, Mossoro-RN. The statistical design was completely randomized with five treatments and four replicates, each with 25 seeds. The treatments consisted of salt concentrations (0.5, 1.5, 3.0, 4.5 and 6.0 dS m-1), obtained by adding NaCl to water so that the solutions were calibrated to the pre-established electrical conductivity values. The variables measured were: percentage of seedling emergence, rate of emergence, leaf area, seedling height, number of leaves, root length and shoot dry weight. Salinity negatively affects all variables directly proportional to its increase in the irrigation water, with the greatest seedling development at a dose of 0.5 dS m-1.

CARACTERIZAÇÃO BIOMÉTRICA DE FRUTOS E SEMENTES DE Sapindus saponaria L.

Pertencente à família Sapindácea, Sapindus saponaria L. é conhecida vulgarmente por saboneteira, saboeiro, sabão-de-macaco, sabonete e fruta-de-sabão, é uma árvore encontrada nos EUA, México, Argentina e Brasil, onde ocorre nos estados do Amazonas, Goiás, Mato Grosso e Mato Grosso do Sul, árrvore perenifólia ou semidecídua, heliófita, de pequeno porte (até 8m), utilizada em paisagismo e em modelos de recuperação de áreas degradadas. A madeira é moderadamente pesada, dura, compacta, de baixa durabilidade natural e é empregada na construção civil, para confecção de brinquedos, caixotaria, etc. Além disso, os frutos contêm saponina, e são utilizados na lavagem de tecidos, as sementes são utilizadas em artesanato e como “bolas-de-gude”, as sementes também são utilizadas na medicina popular como calmante, adstringente, diurético, expectorante, tônico, depurativo do sangue e contra tosse (LORENZI et al. 1992). A descrição biométrica de frutos e sementes fornece informações importantes sobre a qualidade dos lotes de sementes, subsídios esses que ajudam na diferenciação de espécies do mesmo gênero e é importante para detectar a variabilidade genética dentro de populações de uma mesma espécie (ANDRADE et al., 2010). Está relacionada a fatores ambientais, principalmente quando estas possuem ampla distribuição geográfica e adaptação a diversos ambientes, e como também é importante ferramenta em programas de melhoramento genético. (SANJINEZ-ARGANDOÑA & CHUBA 2011; GONÇALVES et al. 2013).

Seeds Collected from Different Ziziphus joazeiro Plants Are Differently Affected by Gibberellic Acid

Ziziphus joazeiro is a tree endemic to Caatinga, Northeastern Brazil, with great economic potential. However, its commercial production is still limited due to low and non-uniform germination of seeds. Recently we demonstrated that gibberellic acid (GA3) stimulates the emergence and uniformity of seedlings in this species. In its natural habitat, however, great morphological diversity between Z. joazeiro trees is found, suggesting great genetic variability. Therefore, it was necessary to test if the GA3 effect is a general response. We collected seeds from four plants maintained in a collection. The plants were selected according to contrasting morphological characteristics. After breaking impermeability with 98% sulfuric acid, the seeds were treated with 2 mmol L−1 GA3 or a control with distillated water for 24 h. Effects ranged from great, low, and no effect of GA3 stimulating the percentage and rapidity of emergence between genotypes tested. For reforestation, thus, the GA3 treatment of Z. joazeiro seeds might reduce its genetic variability; but for economic production, it will be an adequate and simple treatment to increase the quantity and uniformity of seedlings.