-The use of chemical seed treatment is an important tool in the protection of seedlings and has contributed to the increase of rice yield (Oryza sativa L.). The objective of this study was to evaluate the physiological quality and quantify the retention of chemical products in rice seeds treated with insecticide and fungicide coated with polymers. Six seed treatments were used: control, phytosanitary treatment and phytosanitary treatment and coating with the polymers, Florite 1127 ® and VermDynaseed ® polymers were efficient at retaining thiamethoxam in the rice seeds, preventing some of the active ingredients of the insecticide from being leached through the sand columns immediately after the simulated pluvial precipitation.
-The objective of this study was to evaluate methods of overcoming dormancy, light regimens, temperature and depth of sowing variations in the physiological quality of Echium plantagineum seeds. The diaspores (agglutinated fruits from the seeds) were submitted to treatments using accelerated aging, potassium nitrate and gibberellic acid to overcome dormancy. A 7 x 2 factorial design was used to evaluate the temperatures (5, 10, 15, 20, 25, 30 and 35 °C) and light regimens (presence or absence of light). A 6 x 2 factorial design was used for sowing depth (0, 1, 2, 3, 4 and 5 cm) and soil coverage (presence or absence of straw). In all experiments, a completely randomized design with four replicates of 50 diaspores was used. The main evaluations were germination, first germination count, germination speed index and emergence. The seeds showed dormancy, which was overcome by the immersion of the diaspores in potassium nitrate and gibberellic acid. The ideal temperature for germination was 20 °C, showing greater germination in the presence of light, considered as preferentially positively photoblastic. The highest germination percentage occurred when the diaspores were positioned on the soil surface in the presence of straw.Index terms: gibberellic acid, purple flower, photoblastism, potassium nitrate, straw. Germinação de sementes de Echium plantagineum L. submetidas à superaçãoda dormência e variações na temperatura, luz e profundidade de semeadura RESUMO -Objetivou-se avaliar métodos de superação da dormência, regimes de luz, variações da temperatura e profundidade de semeadura na qualidade fisiológica de sementes de Echium plantagineum. Para isso, os diásporos (fruto concrescido das sementes) foram submetidos a tratamentos utilizando envelhecimento acelerado, nitrato de potássio e ácido giberélico para a superação da dormência. Utilizou-se um fatorial 7 x 2 para avaliar temperaturas (5, 10, 15, 20, 25, 30 e 35 °C) e regimes de luz (presença ou ausência). Já para profundidade de semeadura (0, 1, 2, 3, 4 e 5 cm) e cobertura de solo (presença ou ausência de palha) utilizou-se um fatorial 6 x 2. Em todos os experimentos foi adotado o delineamento inteiramente casualizado com quatro repetições de 50 diásporos. As principais avaliações realizadas foram germinação, primeira contagem de germinação, índice de velocidade de germinação e emergência. As sementes apresentam dormência, sendo superada pela imersão dos diásporos em nitrato de potássio e ácido giberélico. A temperatura ideal para a germinação foi 20 °C, apresentando maior germinação na presença de luz, sendo consideradas fotoblásticas positiva preferencial. A maior porcentagem de germinação ocorreu quando os diásporos foram posicionados na superfície do solo, na presença de palha.Termos para indexação: ácido giberélico, flor roxa, fotoblastismo, nitrato de potássio, palha.
This study evaluated the physiological quality and quantified the efficiency of polymer in reducing the loss of phytosanitary products by leaching from soybean seeds of different diameters and in different treatments. Two lots of seed and two types of treatments were tested: polymers associated with seed treatment, and polymer application in layers after the seed treatment. For that, the following treatments were analyzed: Control= no seed treatment; Treat+pol= seed treatment + polymers in the mix; Treat/pol= seed treatment + polymers applied in layers; Treat= seed treatment. To evaluate seed treatment retention by the polymers, extraction equipment was employed and leaching of the active ingredient thiamethoxam was quantified. Evaluation of physical quality was conducted with tests of germination rate, first count, emergence rate, accelerated aging, seedling length, seedling dry mass and moisture content. Polymer application associated with seed treatment was efficient in reducing losses by leaching, reducing product loss by 20%. No significant differences in retention and physiological quality were found when different methods for polymer application were compared. Bigger seeds presented greater vigor, but the germination rate was unaffected.
Salicylic acid acts on several plant physiological processes. Therefore, the aim of this study was to determine if salicylic acid interferes on the physiological quality of common bean seeds soaked with different concentrations by testing two seed imbibition methodologies. Common bean seeds of the cultivars Fepagro 26 and Predileto were utilized. The seeds were soaked in solutions of salicylic acid with concentrations of zero, 250, 500, 750, 1,000, 3,000 and 5,000 μM. Seed imbibition occurred in two ways: (1) germination paper moistened with salicylic acid solutions, and (2) seed imbibition in salicylic acid solutions in plastic boxes for 24 hours and subsequent sowing on germination paper moistened with distilled water. The experiment was maintained in a germination incubator under 25 °C temperature and with constant light. The number of normal seedlings (first count), length, fresh and dry matter of seedlings were determined on the fifth day after sowing. Germination percentage was assessed nine days after sowing. The study was performed in a completely randomized design with four replicates and 50 seeds were used for each treatment. Regression analysis was performed for salicylic acid concentrations, with no comparison of cultivars and seed imbibition methods. Salicylic acid in concentrations up to 1,000 μM does not negatively affect the common bean seed germination of the cultivars Fepagro 26 and Predileto, using seed soaking for 24 hours and imbibition in the germination paper. Concentrations of salicylic acid up to 1,000 μM and seed imbibition for 24 hours do not affect the vigor (first count) of the two common bean cultivars.
The objectives of this work were to evaluate and adequate the method of thermotherapy via humid heat for the treatment of safflower seeds (Carthamus tinctorius L.) and, to verify its effect on the physiological and sanitary quality of seeds. The experiment was performed in the period from September to November, 2016 and from May to July, 2017, in entirely randomized design, arranged in 5 × 6 + 1 factorial scheme, with five temperatures: 25, 35, 45, 55 and 65 ºC and with six time periods: 5, 10, 15, 30, 45 and 60 min, plus the additional treatment (control), with eight repetitions. The seeds were packaged in glass of 500 mL and disposed in thermodigital water bath device with heated water according to the abovementioned factorial. We evaluated the degree of humidity of the seeds after thermotherapic treatments, the germination of normal seedlings, the emergence at field, the speed indexes of germination and emergence, the length and dry mass of seedlings and the sanity test. We observed that the treatment of seeds via humid heat thermotherapy was efficient in the control of phytopathogens, without damage to the physiological quality until 45 ºC. The treatment of 45 ºC for 15 min provided the greater reduction of the pathogens on the safflower seeds, incrementing its germinative potential and emergence at field.
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