Physiological quality and enzymatic activity of crambe seeds after the accelerated aging test

O crambe é uma cultura promissora para produção de biodiesel, principalmente pelo alto conteúdo de óleo de suas sementes. No entanto, não há metodologias estabelecidas para avaliar a qualidade fisiológica das sementes desta espécie e lotes não podem ser comparados, especialmente por testes de vigor, como o de envelhecimento acelerado. O objetivo da presente pesquisa foi avaliar o efeito da alta temperatura e do período de exposição durante o teste de envelhecimento acelerado na qualidade fisiológica e atividade enzimática de sementes de crambe. Dois lotes de sementes de crambe, cultivar Brilhante, foram analisados por meio dos testes de teor de água, massa de 1.000 sementes, germinação, primeira contagem, condutividade elétrica, atividade enzimática (peroxidase e superóxido dismutase) e comprimento de plântulas. As avaliações foram conduzidas antes e após o envelhecimento acelerado, que foram testadas diferentes temperaturas (38, 40 e 42ºC) e períodos de exposição (24, 48 e 72h). O delineamento experimental foi o inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey (p < 0.05). O teste de Dunnet (p < 0.05) foi utilizado para comparar os valores da testemunha (antes do envelhecimento acelerado) com cada valor médio individualmente. O teste de correlação linear simples também foi aplicado. Conclui-se que a interação temperatura x período de exposição afeta a qualidade fisiológica das sementes e a atividade enzimática e que as melhores condições durante o teste de envelhecimento acelerado são dependentes do genótipo.

PHYSIOLOGICAL QUALITY OF OSMOPRIMED EGGPLANT SEEDS

Eggplant seeds germination can be slow and uneven, justifying the use of pre-germinative treatments to improve the performance of seed lots. One option of treatment is the controlled hydration of seeds by priming. In this way, this study aimed to evaluate the performance of eggplant seeds cv. Embu submitted to different methodologies of priming. The seeds used in the experiment were stored in cold chamber (15 degrees C and 55% RH) in paper bags. The research was carried out at Central Laboratory of Seeds/UFLA. The seeds were submitted to the priming in aerated solutions varying the following factors: temperature (15 degrees C and 25 degrees C), time (24, 48 and 72 hours) and solution (water, PEG, KNO3 and PEG+KNO3). Seeds were washed in running water and dried at 30 degrees C, until the return to the initial moisture content, around 10%. The variables analyzed were percentage of germination, percentage of emergence, speed index of emergence and electrical conductivity. The treatments were arranged in a completely randomized design, according to a factorial arrangement 2x3x4+1 (control - seeds without priming). The results showed that priming improves the vigour of eggplant seeds with no effect on viability; the priming in water or KNO3 is efficient to improve the seed vigour and priming in water or KNO3 may use temperature of 15 degrees C or 25 degrees C for 24, 48 or 72 hours.

Physiological quality of osmoprimed eggplant seeds

Eggplant seeds germination can be slow and uneven, justifying the use of pre-germinative treatments to improve the performance of seed lots. One option of treatment is the controlled hydration of seeds by priming. In this way, this study aimed to evaluate the performance of eggplant seeds cv. Embu submitted to different methodologies of priming. The seeds used in the experiment were stored in cold chamber (15º C and 55% RH) in paper bags. The research was carried out at Central Laboratory of Seeds/UFLA. The seeds were submitted to the priming in aerated solutions varying the following factors: temperature (15º C and 25º C), time (24, 48 and 72 hours) and solution (water, PEG, KNO3 and PEG+KNO3). Seeds were washed in running water and dried at 30º C, until the return to the initial moisture content, around 10%. The variables analyzed were percentage of germination, percentage of emergence, speed index of emergence and electrical conductivity. The treatments were arranged in a completely randomized design, according to a factorial arrangement 2x3x4+1 (control - seeds without priming). The results showed that priming improves the vigour of eggplant seeds with no effect on viability; the priming in water or KNO3 is efficient to improve the seed vigour and priming in water or KNO3 may use temperature of 15º C or 25º C for 24, 48 or 72 hours.

Lignification of the plant and seed quality of RR soybeans sprayed with herbicide glyphosate

Differences in levels of lignin in the plant between conventional and transgenic cultivars RR has been reported by several authors, however, there are few studies evaluating the influence of spraying of glyphosate on the lignin in the plant and RR soybean seeds. The aim of this study was to evaluate the physiological quality of RR transgenic soybean seeds and the lignin contents of plants sprayed with the herbicide glyphosate. The assays were conducted both in greenhouse and field in the municipality of Lavras, MG, in the agricultural year 2007/08. The experiment was arranged in a splitplot design with four replicates, considering the treatments hand weeding and herbicide glyphosate as plots, and five RR soybean cultivars (BRS 245 RR, BRS 247 RR, Valiosa RR, Silvânia RR and Baliza RR) as splitplots. In the greenhouse, the cultivars tested were BRS 245 RR and Valiosa RR in a randomized block design with four replicates. The sprayings were carried out at stages V3, V7 and early R5 (3L/ha). The 1000 seed weight, mechanical injury, germination and germination velocity index, emergence velocity index, accelerated aging, electrical conductivity and water soaking seed test, lignin content in the seed coat, in the stem and legumes were determined. The spraying of glyphosate herbicide, in greenhouse and field, did not alter the physiological quality of seeds and the lignin contents in the plant.

Grain yield and seed quality of soybean selected for high protein content

The objective of this work was to evaluate the effects of selection for high protein on seed physiological quality and grain yield of soybean. Four populations of BC1F4 and four of F4, each from a cross between a commercial variety and a line bearing high protein seeds, were used. The high protein content selection has a tendency to affect negatively the seed physiological quality. Estimates of correlation coefficients between protein content and grain yield were mostly negative but varied among populations. It is possible to obtain lines with high protein content, keeping the grain yield and the seed physiological quality of their respective recurrent progenitors.

Several regulations in gravity table in quality of tobacco seeds

The use of gravity table can result in improved quality of seeds of several species, demonstrating the superiority of the quality attributes of seeds collected in the top positions in relation to the lower positions of the discharge zone of the gravity table. The availability of information on tobacco seeds, particularly on the action of gravity table, has not been addressed in the literature. The present study was to evaluate the influence of different regulations in the gravity table on the quality of tobacco seeds. The terminal edge of the machine of 50 cm width was divided into four parts plus the outlet for stones. The treatments were in the following fractions: original seed (obtained in the feed hopper), heavy seed (at the top), middle high, intermediate, and light seed (lower part), and the stones outlet of the gravity table. Each combination of regulation was in an independent adjustment with a total of seven adjusts. The gravity table, in the adjustments with high oscillation, was efficient in improving the physiological quality of seed lots of tobacco, by removing the fraction of light seeds discharged at the bottom of the terminal edge.

Adzuki beans (Vigna angularis) seed quality under several drying conditions

This study analyzed the drying process and the seed quality of adzuki beans (Vigna angularis). Grains of adzuki beans, with moisture content of 1.14 (decimal dry basis) at harvest and dried until the moisture content of 0.11 (decimal dry basis.) were used. Drying was done in an experimental drier maintened at controlled temperatures of 30, 40, 50, 60, and 70 ºC and relative humidity of 52.0, 28.0, 19.1, 13.1, and 6.8%, respectively. Physiological and technological seed quality was evaluated using the germination test, Index of Germination Velocity (IGV), electrical conductivity, and water absorption, respectively. Under the conditions tested in the present study, it can be concluded that drying time for adzuki beans decreases with the higher air temperatures of 60 and 70 ºC, and it affected the physiological and technological seed quality. Thus, to avoid compromising adzuki seeds quality, it is recommended to promote its drying up to 50 ºC.

Physiological and enzymatic alterations in papaya seed during storage

This study was done to evaluate the physiological and enzymatic alterations in papaya (Carica papaya L.) seeds during storage period. Seeds were extracted from mature fruits of Formosa group papaya hybrid Tainung 01. The sarcotesta was removed by rubbing the seeds on a wire screen under running water and then dried to the moisture content (MC) of 5, 8 or 11% The seeds were packed in multilayer paper bags, polyethylene bags, aluminum foil pouch and metallic canisters and stored for 15 months under laboratory conditions. Seeds were evaluated, at three month interval, for MC, germination, and the activity of acid phosphotase (AP) and malate dehyrogenase (MDH) was evaluated with the use of amide gel (12%) electrophoresis. The fresh seeds had post-harvest dormancy, which was broken after six month storage. Independent of the package type, the seeds could be stored for 12 months with 8 or 11% MC under ambient conditions. There was no association between seed deterioration and alterations in AP and MDH activity.

Osmotic priming methodologies in relation to the physiological performance of rangpur lime seeds (Citrus limonia Osbeck)

Several mechanisms have been used to promote rapid germination of citrus seeds and uniform seedling emergence. We evaluated the effects of osmotic priming on the physiological performance of Rangpur lime seeds (Citrus limonia Osbeck). Seeds were treated with 30 g of Captan and 10 g of Tecto 600 in 20-litre batches and stored, without drying, at 10 ºC and 50% relative humidity for periods of 3, 6 and 9 months. After each period, seeds were primed at 25 ºC, in the light, by immersion in Poliethylenoglicol (PEG 6000), potassium nitrate (KNO3) and 70% PEG 6000 plus 30% KNO3, all at an osmotic potential of -1.1MPa, for priming periods of 3, 6, 9 and 12 days. Percentage germination, tray emergence and the emergence rate index (ERI) were evaluated. Priming in PEG 6000 solution, independent of priming period, or in KNO3 or PEG 6000 plus KNO3 for up to 9 days, were efficient at improving the physiological performance of seeds stored for up to 3 months. Osmotic priming appears to be a promising technique for improving the physiological quality of Rangpur lemon seeds.

Test of exudates color hues for evaluating the physiological potential of coffee (Coffea arabica L.) seeds

Coffee seeds have slow and irregular germination, losing fast their viability during storage, and the standard germination test of these seeds requires at least 30 days. Besides, the results may not reflect the actual physiological quality of these seeds. The objective of this work was to develop a fast and practical test for evaluating the viability of coffee seeds, which is based on the interpretation of different color hues of exudates from seeds. Coffee seeds of the cultivar Catuai 44 from six lots were submitted to germination, accelerated aging, and electrical conductivity tests. In the exudates color hue test, coffee seeds without the parchment and the silvery pellicle (four replications of 10 seeds each) were distributed on top of paper towels moistened and then maintained into a germinator, at 25 ºC for 24, 48, 72, 96, and 120 h. Three classes of color hues were established: colorless, light color hue, and dark color hue, assigning the values of 0, 1, and 3, for each class, respectively. The proposed exudates color hue test can be recommended for the fast assessment of viability for coffee seeds. The most promising results were obtained for seeds with 12% moisture content, after imbibition periods of 72, 96, and 120 h; and with 30% moisture content, after imbibition periods of 72 and 120 h.

RR soybean seed quality after application of glyphosate in different stages of crop development

In consequence of several studies and speculations concerning the issue of RR transgenic soybean after the application of glyphosate, additional scientific investigations became necessary to clarify the actual viability of the product use when applied in different developmental stages of the soybean crop. Therefore, this study was aimed to evaluate the physiological quality as well as seed health quality of RR soybean subjected to application of the herbicide glyphosate in different phonological stages of the transgenic soybean, cultivar CD 219RR. For this, an experiment with a complete block experimental design with treatments randomly distributed within the block, with four replications, was carried out. The assessed treatments were foliar sprayings of glyphosate in three increasing dosages [0 (control); 1,440 g ha-1; and 2,880 g ha-1] of acid equivalent, applied in two crop developmental stages: vegetative (V6) and reproductive (R2). The variables assessed were: germination; first count of germination; fresh and dry mass of seedlings, lengths of seedling and root; vigor and viability by the tetrazolium test; and seed health quality. Glyphosate application may adversely affect physiological quality of RR soybean seeds, when applied in dosages varying from 1,440 to 2,880 g acid equivalent per hectare at the stages V6 and R2.

Physiological maturity of eggplant seeds

Determination of seed physiological maturity and ideal moment for harvesting fruits to extract their seeds are important aspects to produce seeds with high quality. To identify the best period for harvesting eggplant fruits, associated with ideal resting period of the fruit for extracting seeds, an eggplant production field was installed in municipality of Ijaci, in the State of Minas Gerais, Southwestern Brazil. The fruits were harvested at periods of 49, 56, 63, 70, and 77 days after pollination (DAP). The seeds of fruits harvested in each period were manually extracted immediately after harvest or after a post-harvest resting period of seven days, under a shed. The physiological quality of seeds was assessed by tests of: germination percentage; germination and emergence speed indexes; and electrical conductivity; which were carried out in the Central Seed Laboratory, Federal University of Lavras. Electrophoretic analyses of isoenzymes: catalase (CAT); esterase (EST); superoxide dismutase (SOD); and peroxidase (PO), were also therein performed. Results of germination and vigor of seeds have showed that the best period for harvesting the fruit is around 70 DAP; and that seeds should be extracted immediately after harvest. Electrophoretic analysis of enzymes has showed immaturity for eggplant seeds, harvested after 49 DAP.

Relationships between physical, morphological, and physiological characteristics of seeds developed at different positions of the ear of two maize (Zea mays L.) hybrids

Maize seeds developed at different portions of the ear of two hybrids (one, a large seeded, and the other a small seeded hybrid) were compared as to physical positions, morphological, and physiological characteristics viewing to gain information to be used during seed conditioning. The number of positions in the ear were 10, starting at the proximal and ending at the distal end. For the sake of simplification, the data were combined to refer to seeds of the proximal, the central and the distal sectors of an ear. Measurements made of the seeds as to shape (length, width, and thickness) and as to size (1,000 seeds weight) indicated that the round seeds growing at the distal sector are significantly smaller (mainly when thickness is considered) and lighter than those growing at the proximal sector. on the other hand, determinations of the physiological quality indicated that the round-proximal and the central seeds are equivalent and both significantly superior to the round-distal ones, Considering these significant differences as to size, shape, and physiological quality, a proposition of suppressing part of the round-distal from the totallity of the round seeds during the operations of seed conditioning is made.

Phosphorus rates on yield and quality of lettuce seeds

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Yield and quality of carrot seeds, cv. Brasilia, as a result of plant population, gibberellic acid and stage of maturity

'Brasilia' is a cultivar of carrot with characteristics suiting cultivation under hot conditions but with problems in seed production, arising from the conflicting requirements of root and seed production. One solution is to select cultivars requiring vernalisation and then to use GA(3) to induce flowering where the climate prevents this. There is, however, little information on plant population, seed maturity and harvesting time on which to base such a procedure. Accordingly this research was carried out to study the physiological quality and production of the seeds in plant populations from 25,000 to 800,000 plants/ha, in the seed-to-seed method of cv. Brasilia in Anapolis, GO, Brazil. In each population, two harvest methods (from first and second orders of umbels, or selected harvest, and remaining orders, or total harvest) and two stages of maturity (brownish, or mature seeds, and yellowish, or immature ones) were also evaluated. Two trials were carried out, with and without gibberellic acid. Seed was evaluated for physical characters, germination, vigour, 1000-seed weight, water content, dry matter and productivity. Seed was produced in both experiments (with or without GA3 spraying). Mature seed showed germination at least 30% greater than immature, and seed from the selected harvest showed germination 16% greater than from the total harvest. In increasing plant population to 200,000 plants/ha, seed quality was not affected, but productivity increased.