Lilian Madruga de Tunes

Envelhecimento acelerado em sementes de azevém com e sem solução salina e saturada

The objective of the present study was to evaluate the methodology of the accelerated aging test to evaluate the physiological potential of s ryegrass seeds, as well as verify the possibility of the use of unsaturated and saturated solution of NaCl as an option for control of water uptake by seeds during the test without reducing its sensitivity. Four lots of ryegrass seeds were tested for germination, seedling emergence, speed emergence and accelerated aging (periods of 24, 48, 72 and 96h, with or without the use of saturated and saline solution of NaCl). The use of unsaturated and saturated solution of NaCl reduces water absorption by ryegrass seeds during the accelerated aging test, resulting in a rate of deterioration is less pronounced ,less drastic and more uniform results. Option 24h with unsaturated solution (SNS) was only able to stratify plots into two groups and should not be designated as promising. Thus, it should be used the 48h saturated NaCl solution (SSS), which stratified into three lots.

Teste de lixiviação de potássio para a avaliação do vigor de sementes de arroz

The aim of this study was to determine the conditions of the potassium leaching test for evaluating rice seed vigor. Five seed lots of the IRGA 424 variety and five seed lots of the Puita Inta CL variety were tested, and results compared with those from germination tests, first germination count, cold test (without soil), electrical conductivity and seedling germination in the field. The amount of potassium leachate was determined using a flame photometer, after 30, 60, 90, 120, 150 and 180 minutes of immersing 50 seeds in distilled and deionised water at volumes of 20 and 50 mL at 25 oC. The combination of 50 pure seeds submerged in 50 mL of distilled and deionized water at 25 oC for 60 minutes was the most efficient procedure for classifying the physiological quality of rice seed lots.

Critical levels of organic acids on seed germination and seedling growth of wheat

The objective of this study was to determine the responses of the wheat cultivars CD 108 and CD 111 for tolerance to organic acids. The effects of five concentrations of the three main acids formed in the soil were studied: acetic acid (0, 4, 8, 12 and 16 mM), propionic acid (0, 4, 8, 12 and 16 mM) and butyric acid (0, 2, 4, 8 and 12 mM). Tests included germination, shoot length, root length and dry weight of shoot and root. The variable root length is the most responsive variable for all the acids tested and the critical level of toxicity of acetic, propionic and butyric acids, which reduced root length by at least 50% was 9.0, 8.5 and 4.0 mM respectively. It was concluded that the presence of acetic, propionic and butyric acids in the germination substratum of wheat seeds of the cultivars CD 111 and CD 108 reduced seedling development, mainly by reducing the length of the radicles.

Tratamento de sementes de trigo com zinco: armazenabilidade, componentes do rendimento e teor do elemento nas sementes

The objective of this study was to evaluate the effects of seed treatment with zinc in zinc content and storability in seed as well as the components of yield of crops whose seeds were coated with doses 0, 1, 2, 3 and 4mL zinc sulfate (ZnSO4 kg-1) more fungicide, polymer and water, then were stored for six months in the environment without control of temperature and relative humidity. Before sowing the seeds were evaluated by germination test, and yield components were evaluated: number of spikelets per plant, number of grains per spikelet and grain weight per plant. After storage for six months assessed the zinc content in the seeds. The zinc coating shall not affect the viability of wheat seeds stored for six months, and further increases in the number of grains per spikelet and grain weight per plant. The zinc content in the seeds increased linearly with increasing doses of ZnSO4 via seed coating.

Detecção e influência de Fusarium spp. na qualidade fisiológica de sementes de pepino

Este trabalho teve por objetivo isolar, identificar e selecionar isolado(s) de Fusarium spp. em sementes de pepino e verificar a sua influencia na qualidade fisiologica. Foram utilizados tres sublotes e os tratamentos consistiram em: testemunha absoluta; BDA + manitol - 0,8Mpa; BDA; BDA + manitol - 0,8Mpa + fungo; e BDA + fungo. A qualidade fisiologica foi avaliada atraves de testes em laboratorio e casa de vegetacao. Cinco isolados de Fusarium verticillioides foram identificados e a sua transmissao atraves das sementes para plantas nao foi possivel afirmar. A tecnica da restricao hidrica foi eficiente para proporcionar infeccao das sementes, sabendo que e o fungo influencia negativamente na qualidade fisiologica das sementes de pepino da cultivar Caipira.

Envelhecimento acelerado em sementes de trigo

This research aimed to study procedures for conducting the accelerated aging test to determine the physiological potential of wheat seeds. The experiment was conducted with four varieties: Pampeano, Sapphire, Onyx and Jasper. Tests were performed with water content, germination, seedling emergence, speed of emergence and accelerated aging. The accelerated aging test was conducted in three stages: traditional (water), test using saturated NaCl solution (11g of NaCl per 100mL of water) and with the use of supersaturated solution of NaCl (40g of NaCl per 100mL of water), each for 48, 72 and 96h at 42°C. The accelerated aging test with saturated solution of NaCl, within 96h was suitable to evaluate the physiological potential of seeds of wheat in high, medium and low vigor.

Ácidos orgânicos na qualidade fisiológica de sementes de arroz

O alagamento do solo para o cultivo do arroz irrigado promove condicoes anaerobias que favorecem a producao de acidos orgânicos de cadeia curta, os quais podem ser toxicos para a cultura. No presente trabalho, o objetivo foi avaliar a qualidade fisiologica de sementes de arroz irrigado cultivar IRGA 424, submetidas ao estresse por diferentes acidos orgânicos, sendo selecionados aqueles formados no solo: acetico, propionico e butirico, utilizando-se as doses de 0, 4, 8, 12 e 16mM, nas quais as sementes foram embebidas por um periodo de 90 minutos e em seguida submetidas a testes de germinacao e vigor (primeira contagem da germinacao, comprimento e massa seca da parte aerea e raizes). Na avaliacao da qualidade das sementes frente ao estresse por acidos orgânicos, o comprimento das raizes foi mais eficiente para diferenciar a toxicidade nas doses de acido acetico, butirico e propionico. O acido butirico foi o mais prejudicial para sementes de arroz, afetando o desenvolvimento inicial das plântulas da cultivar IRGA 424.

Inoculation methods of Alternaria alternata and A. dauci in parsley seeds and their influence on the physiological quality

The objective of the study was to evaluate the effect of the association of Alternaria alternata and A. dauci on the physiologic quality of parsley seeds inoculated by two methods: conidia suspension and water restriction. For the inoculation with suspension, a solution containing 105 conidia of A. alternata, A. dauci and both species (A. alternata + A. dauci), was prepared in which the seeds remained for 30 minutes. For inoculation by water restriction, a PDA medium was prepared, supplemented with 33.1 g/L of manitol, in which the A. alternata, A. dauci and A. alternata + A. dauci colonies grew. The seeds remain on the plates for 48 hours. After the inoculation, the quality of the seeds was evaluated by testing in the laboratory and greenhouse. The parsley seeds had their physiological quality damaged by association with A. alternata and A. dauci under laboratory conditions, especially in relation to germination, first count germination, abnormal seedlings, percentage of dead seeds and the cold test.