Narjara Walessa Nogueira

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.

Temperaturas e substratos na germinação de sementes de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto)

O pereiro-vermelho e uma especie florestal pertencente a familia Rubiaceae, considerada endemica do bioma Caatinga. O presente trabalho teve como objetivo definir o tipo de substrato e a temperatura mais adequados para a germinacao de sementes de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto). Dessa forma, realizou-se experimento em delineamento inteiramente ao acaso e arranjo fatorial 5 x 4, constituidos pelas combinacoes de cinco substratos (entre areia, sobre areia, rolo de papel, sobre papel e sobre vermiculita) e quatro temperaturas (constantes de 25; 30; 35 °C e alternada de 20-30 °C), com quatro repeticoes de 25 sementes cada. Foram analisadas as seguintes variaveis: porcentagem de germinacao, porcentagem de plântulas anormais, indice de velocidade de germinacao, comprimento e massa seca das plântulas. As temperaturas de 25 e 30 °C e os substratos rolo de papel ou areia sao condicoes ideias para a germinacao das sementes de pereiro-vermelho.

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.

The use of saline aquaculture effluent for production of Enterolobium contortisiliquum seedlings

The use of aquaculture effluent for irrigation of field crops has been suggested as the most appropriate biological method for treatment of this effluent. However, using it for irrigation of tree species in seedling nurseries might be a better alternative to avoid soil salinization and groundwater contamination in agricultural fields. This paper aimed at assessing the production of Enterolobium contortisiliquum seedlings under irrigation with saline aquaculture effluent. The experiment was carried out in a randomized complete block design with four replicates and four seedlings per experimental unit. Each replicate was daily irrigated with five solutions containing different concentrations of saline aquaculture effluent diluted with freshwater (0, 25, 50, 75 and 100% effluent). Despite increasing substrate salinity, the dilution of saline aquaculture effluent in the irrigation water promoted greater shoot growth and higher total dry weight in E. contortisiliquum. Moreover, seedlings treated with low concentrations of this effluent increased their leaf area expansion and chlorophyll content. Therefore, the use of solutions containing 25 and 50% effluent allowed the production of high-quality seedlings. These results suggest that saline aquaculture effluent can be reused to irrigate tree species, enabling a successful integration of aquaculture and agriculture and reducing environmental impacts of improper effluent disposal.

Teste de tetrazólio para avaliação da qualidade fisiológica de sementes de Vigna unguiculata (L.) Walp.

RESUMO - O objetivo do trabalho foi desenvolver procedimentos apropriados para a conducao do teste de tetrazolio com o intuito de verificar a viabilidade de sementes de feijao-caupi. Foram avaliadas duas temperaturas, 35 e 40 °C; tres concentracoes de tetrazolio, 0,05; 0,075 e 0,1%; por tres tempos, 90; 150 e 210 minutos. Paralelamente, foram conduzidos testes de germinacao e emergencia de plântulas, condutividade eletrica e envelhecimento acelerado, estabelecendo-se criterios para avaliacao da viabilidade e vigor. As sementes foram tipificadas em dois grupos, viaveis e inviaveis, as quais apresentaram adequada relacao com a emergencia. A avaliacao da viabilidade e vigor das sementes de feijao-caupi, por meio do teste de tetrazolio, e eficiente com o emprego do pre-condicionamento de imersao direta em agua por 16 horas, a 25 °C, e utilizacao da solucao de tetrazolio na concentracao de 0,05%, por 210 minutos, na temperatura de 40 °C. Palavras-chave: Feijao-caupi. Germinacao. Vigor.

In vitro Germination of Anthurium affine Schott at Half-MS Strength

The Anthurium affine Schott is an aroid of ornamental and medicinal potential; however, its means of propagation are poorly known. The objective of this study was to evaluate in vitro germination of A. affine Schott in two MS (Murashige and Skoog) medium concentrations (100% and 50%) and under two light intensities (light and dark). The experiment was conducted using a 2 × 2 factorial in a completely randomized arrangement. The four treatments were: T1: 100% MS + dark; T2: 50% MS + dark; T3: 50% MS + light; and T4: 100% MS + light. Each treatment consisted of 30 test tubes (replicates). Seven days after setting up of the experiment, plastic cover was removed from the test tubes, and soon thereafter germination was assessed. Twenty-three days later, the number of leaves, plant height, number of roots, and size of the biggest root were recorded. There were no significant differences among the treatments for number of leaves. Mean plant height, the number of roots, and the size of the biggest root were affected by treatments, however, with Treatments 2 and 3 (50% MS) giving bigger values than Treatments 1 and 4 (100% MS). We concluded that the light treatmentdid not affect seed germination of A. affine and that the half-strength MS medium recorded a better plant development, with taller plants and larger and more roots.