Raquel Alves de Freitas

Teste de envelhecimento acelerado em sementes de lentilha

The objective of this research was to examine the efficacy of the accelerated aging test for vigor evaluation of lentil seeds. Four seed lots of the Silvina cultivar were utilized. The initial quality of each seed lot was evaluated by seed moisture content germination at first count, speed of protrusion of primary root, and field seedling emergence. The accelerated aging test was conducted at 41oC for periods of 24, 48 and 72 hours, by the traditional and NaCl saturated solution. The experiment was conducted in a completely randomized design. The saturated salt accelerated aging was efficient for vigor evaluation of lentil seeds, and the period of 48 hours at 41oC was considered as the most adequate procedure to assess seed vigor levels.

Metodologia para o teste de envelhecimento acelerado em sementes de ervilha

Pea production in Brazil uses seeds produced in the country. The objective of this study was to examine the efficiency of the accelerated aging test for vigor evaluation of pea seeds. Five seed lots of cultivar Axe (wrinkled seeds) and five seed lots of cultivar Mikado (smooth seeds) were used. The initial quality of each seed lot was evaluated by germination test, first counting, and seedling emergence in the field. Seed moisture content was also assessed. The accelerated aging test was set at 41oC for periods of 24; 48; and 72 hours, with and without saturated NaCl solution. The experiment was carried out in a completely randomized design. The accelerated aging test was efficient for vigor evaluation of pea seeds, and the period of 48 hours at 41oC, using saturated NaCl solution was the most adequate procedure to indicate vigor levels of pea seeds. However, the seed germination after this period was very low when compared to 24 hour-period (80%) for both cultivars, even in higher vigor seed lots (35% for Axe and 38% for Mikado). In the saturated NaCl solution, the period of 48 hours at 41oC was the most adequate for separate seeds through vigor levels. In these conditions, seed lots of highest vigor showed germination of 68% and 79% for Axe and Mikado, respectively. Results of the germination test, first counting, and seedling emergence were not effective in discriminating physiological seed quality when used individually. Nevertheless, when results from these tests were used all together, it was possible to identify the best seed lots.

Análise de imagens no estudo morfológico e fisiológico de sementes de abóbora

ABSTRACT Image analysis to associate morphological and physiological characteristics in pumpkin seeds Obtain pumpkin seeds with high physiological quality is critical for the domestic seed production in terms of competitiveness with imported seeds. One technique that has recently been used to elucidate the various aspects of seed performance is the analysis of images, including those obtained through X-ray. This technique involves X-ray images of seeds to evaluate the internal morphology and to establish the relationship with the seed performance. Thus, the objective of this study was to determine whether the X-ray technique may help to detect internal abnormalities and to assess the quality of pumpkin seeds. ‘Brasileirinha’ pumpkin fruits were harvested at different maturation stages (30, 40, 50 and 60 days after anthesis). In each stage, seeds were extracted either immediately after harvesting or after 15 days of fruit storage. In the X-ray test, seeds were subjected to an intensity of 25 kV for 40 seconds and then a germination test was carried out at alternate temperatures (20-30°C). The first count was held after four days and the last reading after eight days, computing the percentages of normal and abnormal seedlings and dead seeds. After obtaining the results of the germination test, a comparison of results was done with the images of the internal morphology of each seed, obtained by means of X-ray. The use of X-ray technique is effective in detecting malformed and empty pumpkin seeds and these negatively affect germination.

Utilização de agentes polinizadores na produção de sementes de cenoura e pimenta doce em cultivo protegido

Pollination is a fundamental process for the perpetuation of various plant species, and the development of fruits and seeds is directly related to the pollination of flowers. Thus, the aim of this study was to assess the influence of pollinators on seed production and quality of carrot and sweet pepper under greenhouse conditions. In the carrot study, plants were grown in cages, and the following treatments were used: pollination with Arapua (Trigona spinipes) bees, Jatai (Tetragonisca angustula) bees, Tibuna (Nannotrigona (Scaptotrigona) bipunctata) bees, flies (Musca domestica), hand pollination, and free pollination (outside the greenhouse). In the sweet pepper study, the following treatments were used: pollination with Arapua (Trigona spinipes) bees, Jatai (Tetragonisca angustula) bees, Marmelada (Frieseomellita varia) bees, hand pollination and free (self fertilization). The use of Jatai and Tibuna bees showed a great potential for carrot seed production in greenhouse conditions. For the production of sweet pepper seeds the use of pollinators is not necessary, but the presence of these agents increases the fruit weight. The physiological seed quality of both species was not influenced by different types of pollination.

Maturação e qualidade de sementes de repolho de verão sob condições tropicais.

The effect of maturation stages under tropical conditions, of summer cabbage cv. Uniao fruits (seedpods), was studied on the seed physiological quality. On September, 2005 (200 days after transplanting), seedpods were harvested from racemes in the maturation (color) stages of intensive green, green, purple and beige, resulting in seeds with the predominant colors of green, brown, intensive brown and black, respectively. Part of the harvested racemes was threshed immediately after harvesting and part was stored at laboratory conditions for a week before being threshed. The experiment was conducted in a completely randomized design arranged in a factorial scheme 4 x 2 (seedpod maturation stages and threshing timing). Seeds were submitted to the tests of moisture content, mass of 100 seeds, germination, first counting, seedling emergence in greenhouse conditions and accelerated aging. Physiological seed quality varied among seedpod stages. The results indicated that the racemes with green seedpods may be harvested if the seeds remain for a week into seedpods before threshing.

QUALIDADE FISIOLÓGICA DE SEMENTES DE BERINJELA SUBMETIDAS A DIFERENTES MÉTODOS DE EXTRAÇÃO E SECAGEM

During seed extraction in fleshy fruits, some procedures are necessary to ensure seed quality and minimize deterioration and microorganism activity; also seeds extracted under moist conditions need special care when drying. The objective of this study was to evaluate the physiological quality of eggplant seeds submitted to different extraction and drying methods. In the first study, whole eggplant fruits were mechanically crushed and then fermented for 0, 24 and 48 hours, with and without applying hydrochloric acid during seed extraction. In the second study, seeds were extracted in a pepper peeler and then immediately washed in water and submitted to the following drying methods: Sun/24 h; Sun/48 h; 32 °C/24 h; 32 °C/48 h; 38 °C/24 h; 38 °C/48 h; Sun/24 h + 32 °C/24 h; Sun/24 h + 38 °C/24 h e 32 °C/24 h + 38 °C/24 h. The treatment efficiency of both experiments was evaluated from the following tests: seed weight, germination, first count, accelerated aging and seedling emergence. The results suggest that fermentation and applying hydrochloric acid to pulp/seed reduce the physiological seed quality. All drying methods reduced the seed moisture content permitting adequate storage and maintenance of seed physiological quality.