. Foram coletadas 243 folhas danificadas que antes da coleta tiveram seu perímetro redesenhado com o auxílio de folhas inteiras de formato similar. Após a determinação da porcentagem de área danificada, foram selecionadas imagens para compor a escala diagramática logarítmica. O teste da escala foi realizado por 10 diferentes observadores em 24 folhas sorteadas dentre as 243 coletadas. A acurácia e a precisão de cada avaliador foram determinadas por regressão linear simples entre o dano real e o estimado com o auxílio da escala diagramática, além destes, utilizou-se a Raiz do Quadrado Médio do Erro (RQME), o erro absoluto e o coeficiente de determinação (R 2 ) da regressão linear. Verificou-se que a escala é adequada para observação de dano foliar por granizo. Palavras-chave: Helianthus annuus. Análise foliar. Evento meteorológico.ABSTRACT -The objective of this study was to develop a diagrammatic scale for the visual assessment and the quantification of hail damage in sunflower leaves. The study was carried out in an experimental area in Santa Maria (RS) during the agricultural year of 2008/2009, the damage being caused by a hail-storm event which occurred on 8 January, 2009, with the sunflower plants in full bloom (R5.1) and a leaf-area index of 2.2 m 2 m -2 . A total of 243 damaged leaves were collected, which before collection had their outlines redrawn with the aid of complete leaves of similar shape. After determining the percentage of the damaged area, images were selected to make up the diagrammatic logarithmic scale. A test of the scale was undertaken by 10 different observers on 24 randomly selected leaves from the 243 collected. The accuracy and precision of each appraiser were determined by simple linear regression of actual damage and that estimated with the aid of the diagrammatic scale, in addition we used the Root Mean Square Error (RMSE), the absolute error and the coefficient of determination (R 2 ) of the linear regression. It was found that the scale is suitable for the observation of leaf damage caused by hail.
The objective of this study was to evaluate the photosynthetic and physiological parameters of soybean plants under water deficit after imbibition in different concentrations of salicylic acid during germination. The initial seed quality of the cultivar Bayer®/Tec Irga 6070 RR was evaluated. The soybean seeds were soaked in 25 ml in the salicylic acid solution (SA) for 24 hours and the retention capacities of 30, 50 and 70% were adopted. Under controlled conditions, concentrations of zero, 250, 500, 750 and 1000 µM, evaluating the variables length, fresh and dry mass of root and shoot. In the greenhouse, the concentrations of SA of zero, 500 and 1000 µM were used. After 29 days of the seedling, the stomatal conductance, length, fresh and dry mass of root and shoot were evaluated. The results showed that the uptake of SA in the germination aided seedlings under water deficit. The retention capacity of 30% simulated the water deficit, damaging the physiological parameters of soybean seedlings in both environments. The concentrations of 500 and 1000 µM of SA were efficient in the water deficit for the variables root length, fresh and dry shoot mass.
Algumas espécies da família Cucurbitaceae apresentam dormência de sementes, inclusive o maxixe. Assim, o objetivo deste trabalho foi estudar métodos de superação de dormência em sementes de maxixe. As sementes foram submetidas aos seguintes tratamentos: T1 = Testemunha, T2 = Embebição por 3 dias em água destilada, T3 = Embebição por 4 dias em água destilada, T4 = Imersão em solução de NaClO 10% por 10 minutos, T5 = Imersão em solução de NaClO 10% por 48 horas, T6 = Imersão em solução de NaClO 10% por 10 minutos e secagem em temperatura ambiente por 48 horas, T7 = Imersão em solução de NaClO 10% por 10 minutos e secagem em estufa a 40?C por 48 horas, T8 = Imersão em solução de NaClO 10% por 10 minutos e secagem em temperatura ambiente por 72 horas, T9 = Escarificação química com H2SO4 por 1 minutos, T10 = Escarificação química com H2SO4 por 2 minutos, T11 = Escarificação mecânica com lixa por 10 segundos, T12 = Escarificação mecânica com lixa por 20 segundos. A avaliação dos tratamentos foi realizada pelos seguintes testes: germinação, primeira contagem da germinação, comprimento de raiz e parte aérea de plântula, massa seca de plântula e emergência de plântulas em areia, utilizando o delineamento inteiramente casualizado. A dormência das sementes de maxixe é superada com embebição por quatro dias em água destilada, imersão em solução de NaClO 10% por 10 minutos e secagem em temperatura ambiente por 48 horas e escarificação mecânica por 10 ou 20 segundos.
The objective of this study was to evaluate the physiological quality of commercial soybean seeds submitted to different concentrations of salicylic acid (SA), directly on germination paper and gerboxes for 24 hours. Seeds of cultivars NA 5909 RG and Tec Irga 6070 RR were soaked in salicylic acid solutions with concentrations of zero, 250, 500, 750, 1000, 1500, 2000, 3000, 4000 and 5000 μM. Seed imbibition occurred in two ways: (1) germination paper moistened with salicylic acid solutions; (2) imbibition of the seeds in salicylic acid solutions in gerbox boxes for 24 hours and subsequent sowing on germinated paper moistened with distilled water. On the fifth day after sowing, the number of normal seedlings (first count), length, fresh and dry mass of root and shoot were determined. It was concluded that the concentrations of SA between 250 and 750 μM can be used in soybean seeds, however, above 1000 μM may impair the parameters of physiological quality. The gerbox method for 24 hours provided the best results without the drastic reduction of the parameters in the lowest concentrations of SA.
Rapid tests such as electrical conductivity provide fast and consistent results regarding stratification of seed lots by vigor. They are important tools used to evaluate the physiological quality of seeds of several species, however, no such information was found for Sorghum bicolor. The objective of this study was to evaluate the relationship between the physiological quality of the seeds by the mass and individual conductivity tests. Four plots of the Fepagro 19 cultivar were analyzed through the degree of moisture, weight of one thousand seeds, first count and germination, radicular and shoot length, dry mass, cold test and emergence of field seedlings. Subsequently, they were submitted to mass electrical conductivity experiments with variations in the imbibition time (2, 4, 6, 8, 12 and 24 hours), temperature (20, 25 and 30 º C), number of seeds (25 and 50), volume of water (50 and 75 mL) and individual (2, 4, 6, 8, 12 and 24 hours). The design was completely randomized and the data evaluated by the Tukey test. Only the lowest physiological quality batch was detected in the 20 °C, 75 mL and 25 seeds for 12 hours combinations; the individual test detected the least physiological quality batch, and it was possible to perform it in 24 hours.
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