Maria Clarete Cardoso Ribeiro

Armazenamento de sementes de Catanduva (Piptadenia moniliformis Benth.) em diferentes ambientes e embalagens

This study aimed to evaluate the viability of catanduva seeds stored for 210 days under controlled and uncontrolled environmental conditions (laboratory), in plastic, paper and glass packaging. The experimental design was completely randomized in a sub-subdivided plot, where the main plot were the storage conditions (laboratory and cold room) and sub-plots consisted of the packaging (plastic and paper bags and glass bottles) and sub-sub-plots of the storage times (0, 30, 60, 90, 120, 150, 180 and 210 days). The tests were conducted in the laboratory and greenhouse. Evaluations were made every 30 days of the percentage of germination and the rate of germination velocity in the laboratory and of seedling emergence in the greenhouse. The seed viability of catanduva decreased as a function of storage time during the 210 days. Catanduva seeds (Piptadenia moniliformis Benth.) can be packed for 210 days either in glass bottles or plastic bags without losing their physiological potential. The controlled environment (18-20 oC, ±60% RH) is the most suitable.

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.

Influência de partes vegetais de Tamarindus indica L. como efeito alelopático na germinação da alface

O presente trabalho teve como objetivo avaliar a existencia de substâncias capazes de interferir na germinacao de outras especies, e seu efeito sobre as sementes e plântulas de alface ( Lactuca sativa ). O experimento foi conduzido no laboratorio de analises de sementes do departamento de ciencias vegetais da Universidade Federal Rural do Semi-Arido, Mossoro – RN. O delineamento experimental utilizado foi inteiramente casualizado, em esquema fatorial 4 x 3 + 1, sendo o primeiro fator quatro concentracoes de extrato aquoso de tamarindo (0, 10, 25 e 50%) proveniente de tres partes distintas do vegetal (folha, cascas dos frutos maduro e casca do caule), com quatro repeticoes de 50 sementes. Os parâmetros avaliados foram a porcentagem de emergencia (E), primeira contagem de emergencia (PCE) e indice de velocidade de emergencia (IVE). Os resultados indicaram forte atividade alelopatica presente em todas as regioes estudadas do tamarindo sobre as variaveis analisadas no alface. Apenas a casca do fruto maduro na concentracao de 10% nao influenciou na emergencia, primeira contagem e indice de velocidade de emergencia, com valores na ordem de: 18%, 10% e 0,6, respectivamente .

Gibberellic acid enhances the emergence of Zizyphus joazeiro seeds.

Zizyphus joazeiro (Rhamnaceae) is a native species of the Brazilian semiarid region. It has a very low germination rate, thus complicating the scion production for reforestation projects and commercial use. Several species from Rhamnaceae have been reported to increase germination when treated with gibberellic acid (GA3). The purpose of this work was to study the effect of gibberellic acid on the rate and speed of emergence in this species. Three GA3 solutions (1, 2, and 3 mM), along with a control of distilled water, were evaluated using seeds previously treated with sulfuric acid. The GA3 treatments enhanced the emergence of seeds. Sixty-two days after sowing the GA3 treatment-induced seeds, percentage emergence increased almost five times in comparison with nontreated seeds. However, there was no statistical difference among the three concentrations of GA3. Thus, Zizyphus joazeiro seed treatment with GA3 is simple and adequate for scion production.

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.

Desponte e embebição em sementes de noni (Morinda citrifolia L.)

The study aimed to test the germination of seeds of noni under different soaking times, with and without the seed emerges. For this, an experiment was installed in a greenhouse in a completely randomized design with 10 treatments and 4 replicates of 25 seeds, being composed of: 1. Witness 2. Seeds with the blunt side opposite the embryo 3. Intact seeds with 12 hours of soaking, 4. Intact seeds with 24 hours of soaking, 5. Intact seeds with 36 hours of soaking, 6. Intact seeds with 48 hours of soaking; 7. Seeds with cutting with 12 hours of soaking; 8. Seeds with cutting with 24 hours of soaking; 9. Seeds with cutting with 36 hours of soaking and 10. Seeds with cutting with 48 hours of soaking. The characteristics evaluated were: percentage of emergence, speed of emergence index, seedling height, root length and weight of the dry mass of seedlings 46 days after the experiment. There were significant differences between the different times of soaking and treatment 10 (cutting with 48 hours of soaking) who obtained the best results for the percentage of emergency and emergency speed index and dry weight. The height of the seedling, one treatment (control) was the highest, while in treatment 2 (blunt) registered the largest root length. Although the witness did not differ, the best treatment was the use of blunt + 48 hours of soaking.