Heloisa Oliveira dos Santos

Qualidade fisiológica de sementes de soja submetidas à chuva artificial na pré colheita

The objective of this experiment was to evaluate responses of soybean cultivars seeds (with different levels of lignin) considering harvest postponement under the incidence of water and the effect of storage. The experiment was conducted in Iraí de Minas, Brazil using a randomized block design with three replications under a 5 x 3 x 3 factorial arrangement, with five soybean cultivars (NK 7059 RR, SYN 1163 RR, SYN 9070 RR, AS 7307 RR and SYN 1283 RR), three harvesting periods (R8, R8 + one rain simulation in the pre-harvesting period and R8 + two simulations in the pre-harvesting period) under three storage times (0, 90 and 180 days). Seeds were evaluated for their chemical composition (lignin contents), the percentage of moisture damage using the tetrazolium test and physiological quality (germination, accelerated aging, conductivity test, seedling emergence and emergence index). Cultivar AS 7307 RR had the highest lignin content in the integument, the lowest percentage of damage by moisture and the highest physiological quality. Cultivars NK 7059 RR and SYN 1163 RR had the lowest lignin contents in the integument and the highest moisture damage. Electrical conductivity increased after storing all cultivars.

Influence of lignin content in soybean seed coat on the incidence of the storage fungus Aspergillus flavus

Seed quality may be affected by several factors, including permeability, color, and lignin content in the seed coat. This study aimed at evaluating influence of lignin content in the tegument of seed samples of six different soybean cultivars, in which half of each sample was inoculated with the fungus Aspergillus flavus, on the physical and physiological quality, and on the seed health, during 180 days storage period, under cold chamber with controlled conditions of temperature and RH. For that, at each interval of 60 days, samples were removed, and the physiological quality of these seeds was assessed by means of moisture and lignin contents; and by tests of seed health, germination, and electrical conductivity. The moisture content of seeds remained constant during all storage period. In the seed health test, it was found that inoculation was efficient, once the minimum incidence of the fungus in the inoculated seeds was 85%. In the germination test, there was a trend of reduction on percentage germination with the increase in storage period. However, there was an increase on electrical conductivity of seeds assessed. It was concluded that there is no interference of the lignin content in the seed coat on the resistance to infection by the fungus Aspergillus flavus, even after seed storage for a period of 180 days.

Aspectos fisiológicos e bioquímicos da germinação de sementes de alface em diferentes temperaturas

The objective of this work was to evaluate the electrophoretic patterns of heat-tolerant proteins and the activity of the endo-β-mannanase enzyme during lettuce seed germination, at high temperature. Seeds of eight lettuce cultivars were subjected to germination, first count, and emergence tests at two temperatures, 20 and 35oC. The index of germination speed (IVG) and the emergence rate index (IVE) were calculated. The expression of heat-tolerant proteins and of the endo-β-mannanase enzyme was also evaluated for all treatments. The experimental design was completely randomized, in a 2x8 factorial arrangement, with two temperatures and eight cultivars. The highest germination is observed at 35oC in the Everglades cultivar, considered thermotolerant. The patterns of heat-tolerant proteins in lettuce seeds present specific bands in the Everglades cultivar, at 35oC. The activity of the endo-β-mannanase enzyme is higher in the Everglades cultivar, at this temperature. This cultivar has potential for use in lettuce breeding programs aiming for tolerance to high temperatures during germination.

X-ray test in the evaluation of seed quality of physalis at different stages of development

Injuries in the internal structures of the seeds limit their viability and can reduce their vigor, producing weak seedlings susceptible to adverse conditions. Thus, the determination of the quality of seeds of Physalis peruviana L. by X-ray test is valid, in order to reduce the time separation of seeds and a good initial establishment of the culture. Considering the above, the objective of the present study was to evaluate the quality of physalis seeds at different stages of development of fruit by X-ray test. The seeds were removed and separated into lots according to the fruit maturation stage, being fruits with intermediate maturity (50% of the ripe fruit), completely ripe fruits and completely ripe fruits subjected to seven days of rest after harvest. Posteriorly they were subjected to X-rays for determination of seed quality. The experimental design consisted of eight replicates of one hundred seeds per lot. Physalis fruit seeds with 50% maturation have lower morphophysiological quality when compared to seeds extracted from completely ripe fruits. Seed vigor is greater when the fruits are subjected to rest for seven days. The X-ray test is efficient for selection of non-viable seed of physalis.Injuries in the internal structures of the seeds limit their viability and can reduce their vigor, producing weak seedlings susceptible to adverse conditions. Thus, the determination of the quality of seeds of Physalis peruviana L. by X-ray test is valid, in order to reduce the time separation of seeds and a good initial establishment of the culture. Considering the above, the objective of the present study was to evaluate the quality of physalis seeds at different stages of development of fruit by X-ray test. The seeds were removed and separated into lots according to the fruit maturation stage, being fruits with intermediate maturity (50% of the ripe fruit), completely ripe fruits and completely ripe fruits subjected to seven days of rest after harvest. Posteriorly they were subjected to X-rays for determination of seed quality. The experimental design consisted of eight replicates of one hundred seeds per lot. Physalis fruit seeds with 50% maturation have lower morphophysiological quality when compared to seeds extracted from completely ripe fruits. Seed vigor is greater when the fruits are subjected to rest for seven days. The X-ray test is efficient for selection of non-viable seed of physalis.

Proteins expression and germination of maize seeds submitted to saline stress

Plants are frequently exposed to various biotic and abiotic stresses that impair their growth, development and limit the productivity. In the present work the objective was to evaluate the effect of saline stress on the germination and biochemical alterations by the expression of enzymatic systems in corn seeds treated with different concentrations of NaCl. Hybrid maize seeds (H1, H2, H3) were used during 2013 cropping season and solutions of sodium chloride (NaCl) to simulate the saline stress. The respective concentrations of NaCl (mol.m-3) were zero (0.0 g/L); 25 (1.46 g/L); 50 (2.93 g/L); 75 (4.39 g/L) and 100 mol.m-3 (5.85 g/L), diluted into water. In order to evaluate the physiological potential of these seeds, we realized the germination test with four replications of 50 seeds, distributed between three germitest papers moistened with NaCl solutions, described above. The evaluation was performed on the seventh day, with the first count realized determining the percentage of normal seedlings on the fourth day after planting. The biochemical evaluation was performed by the expression of isoenzymes superoxide dismutase (SOD), esterase (EST), catalase (CAT), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH) and alpha amylase. Seeds of the three tested hybrids have lower germination when placed in conditions of greater concentration of salinity. The hybrid H3 that presents higher tolerance to salinity and hybrid H1 are most susceptible during the germination process. The hybrid with higher vigor, H3 had higher activity of alpha amylase and catalase enzyme groups. Esterase and alcoholic dehydrogenase were not effective in measuring the quality of maize grains under salt stress conditions. Key words: Zea mays, physiological quality enzyme.

Morpho-physiological changes in Billbergia zebrina due to the use of silicates in vitro

The use of silicon in Billbergia zebrina cultivation in vitro is an alternative for optimizing micropropagation of this important ornamental plant species. The objective of the present study was to evaluate the growth and anatomical and physiological alterations in Billbergia zebrina (Herbert) Lindley plants as a function of different sources and concentrations of silicon during in vitro cultivation and acclimatization. The experimental design was completely randomized, with a double factorial arrangement and an additional control treatment (2 x 3 + 1). The first factor was relative to calcium silicate and sodium silicate added to the Murashige & Skoog culture medium; the second factor was related to its concentrations, 0.5, 1.0, and 2.0 mg L-1. After 100 days, their growth, anatomical characteristics, level of silicon and chlorophyll content were evaluated. Growth characteristics were assessed after 60 days of acclimatization period. Plants absorbed more sodium silicate than calcium silicate. This source also stressed the plants impairing their growth, but the highest silicon absorption at 1 mg L-1 attenuated the stressful conditions. The supplementation of the culture medium with calcium silicate led to improved growth, anatomical, and physiological characteristics, which benefited the development of more resistant seedlings with better performance during acclimatization.

Teste de raios X na avaliação da qualidade de sementes de frutos de fisális em diferentes estádios de desenvolvimento

Injuries in the internal structures of the seeds limit their viability and can reduce their vigor, producing weak seedlings susceptible to adverse conditions. Thus, the determination of the quality of seeds of Physalis peruviana L. by X-ray test is valid, in order to reduce the time separation of seeds and a good initial establishment of the culture. Considering the above, the objective of the present study was to evaluate the quality of physalis seeds at different stages of development of fruit by X-ray test. The seeds were removed and separated into lots according to the fruit maturation stage, being fruits with intermediate maturity (50% of the ripe fruit), completely ripe fruits and completely ripe fruits subjected to seven days of rest after harvest. Posteriorly they were subjected to X-rays for determination of seed quality. The experimental design consisted of eight replicates of one hundred seeds per lot. Physalis fruit seeds with 50% maturation have lower morphophysiological quality when compared to seeds extracted from completely ripe fruits. Seed vigor is greater when the fruits are subjected to rest for seven days. The X-ray test is efficient for selection of non-viable seed of physalis.Injuries in the internal structures of the seeds limit their viability and can reduce their vigor, producing weak seedlings susceptible to adverse conditions. Thus, the determination of the quality of seeds of Physalis peruviana L. by X-ray test is valid, in order to reduce the time separation of seeds and a good initial establishment of the culture. Considering the above, the objective of the present study was to evaluate the quality of physalis seeds at different stages of development of fruit by X-ray test. The seeds were removed and separated into lots according to the fruit maturation stage, being fruits with intermediate maturity (50% of the ripe fruit), completely ripe fruits and completely ripe fruits subjected to seven days of rest after harvest. Posteriorly they were subjected to X-rays for determination of seed quality. The experimental design consisted of eight replicates of one hundred seeds per lot. Physalis fruit seeds with 50% maturation have lower morphophysiological quality when compared to seeds extracted from completely ripe fruits. Seed vigor is greater when the fruits are subjected to rest for seven days. The X-ray test is efficient for selection of non-viable seed of physalis.

Estudo bibliométrico sobre organismos vegetais geneticamente modificados

Este artigo apresenta os resultados de uma pesquisa sobre os estudos realizados no mundo sobre o tema “Transgenicos” publicado entre os anos de 1998 e 2014, nos periodicos Pesquisa Agropecuaria Brasileira, Journal Biotechnology, Euphytica, Journal of agronomy and crop Science, Crop Protection, Crop Science, Biotecnologic Review, Seed Science Research, Ciencia e Agrotecnologia, Genetics and Molecular Research. Para atingir esse objetivo foram analisados os seguintes aspectos: (a) o panorama global dos artigos; (b) identificar as revistas com maior numero de publicacoes, (c) a quantidade de publicacoes por seguimentos: Algodao, Soja, Milho, Resistencia a Insetos, Tolerância a Herbicidas e Artigos de Revisao sobre o tema (d) identificar os anos mais produtivos e a tendencia de publicacao ao longo do tempo; (e) identificar os paises que mais publicam (f) identificar as palavras-chave mais recorrentes nos artigos levantados, (g) quantidade de autores por artigos. Foram estudados 138 artigos, e os dados foram analisados por meio de estatistica descritiva e analises bibliometrica. De acordo com os resultados, a revista Crop Protection foi a que mais publicou artigos sobre transgenicos, os Estados Unidos e o pais que lidera o ranking de publicacoes, algodao foi o segmento mais estudado, e como consequencia a palavra Cotton foi a mais recorrente dentre as palavras chave. Os artigos sao em sua maioria escritos por seis ou mais autores.