AJAR (2016), Vol. 1, Issue 05

  • Effect of temperature on bean seed germination: vigor and isozyme expression

    This research aimed to evaluate the physiological quality of seeds and isozyme expression in seedlings of bean’s genotypes under influence of germination temperatures. Seeds of Carioca, BRS Expedito and IPR Tuiuiú genotypes were subjected to five germination temperatures (15, 20, 25, 30 and 35 °C). Seeds were submitted to tests of germination, first count, germination speed index, cold test, isozyme expression and the total dry matter of seedlings. Germination was altered due to the different temperatures. As the temperature rose, seeds of IPR Tuiuiú and BRS Expedito had reduced germination. The increase on temperature significantly affected the germination speed index of the three genotypes, leading to a greater increase in the values of this attribute. Bands of esterase from the cold test showed less intensity compared to other tests. Due to the exposure to different temperatures, there are similarities between the number and intensity of bands on esterase, with lower enzyme expression at 30 and 35 °C, changes in the number and intensity of peroxidase expression at all temperatures, and practically none expression of the acid phosphatase enzyme in higher evaluated temperatures. Therefore, the seeds exhibit better performance when exposed to temperature of 30 °C compared to use of lower temperatures, while on temperatures above 30 °C isozymes expression is reduced for both genotypes.

  • Characterization of fire occurrences (2010-2014) in the southeast of Brazil

    The periodic occurrence of forest fire is common in some places of Brazil. Mostly in places, that has a specified dry station, these fires can damage the forestry ecosystems, and their occurrence may affect the wild life and bring economic losses, as well in CO2 global emission. The aim of this study was define the fire season occurrence in Viçosa – Minas Gerais state Brazil, using five years data of fire and rainfall collected by the Fire Fighters. The study was made through the data from the firefighters from UFV, this data was evaluate for a period between 2010 and 2014, collecting the days and months that occurred fire in Viçosa city and outskirts, also the average precipitation data for the period. The observations showed that to Viçosa city, the occurrence of fire is mostly common in the July to October months, and August is the most susceptible month.

  • Erwinia chrysanthemi, rhizospheric earthworms, sorghum, vermicompost

    Bioagents colonized vermicompost can be a crucial alternative natural biological control of stalk rot diseases of sorghum because of the hazardous effects of agrochemicals on non-targeted organisms and soil health. To study the interaction among bioagents colonized vermicompost with stalk rot disease of sorghum caused by Erwinia chrysanthemi, and earthworms of rhizospheric soil, pre-plant soil application of bioagents colonized vermicompost @ 2.5 kg/4 m2 and chemicals viz. Blitox-50, Bleaching powder, Streptocyclin and Tetracyclin @ 2.5% were done under field conditions. In analysis of earthworm’s population dynamics, maximum numbers of young earthworms per plant rhizosphere were observed with vermicompost colonized isolate Th-2 followed by vermicompost alone and vermicompost colonized isolate Psf-24. However, minimum number of young earthworms per plant rhizosphere was obtained with Bleaching powder. Maximum seed germination was recorded with vermicompost colonized isolate Th-2 followed by Th-R, Th-14, and Psf-12. Maximum number of earthworm’s heap of cast per plant rhizosphere was obtained in plants treated with vermicompost colonized isolate Th-2 followed by Psf-19, Psf-12 and Psf-18. Significant increase in biomass yield of sorghum plants were observed among all the treatments. However, maximum biomass yield was observed with vermicompost colonized isolate Th-2 followed by Psf-24. Maximum reduction of disease severity was recorded with vermicompost colonized isolate Th-2 followed by Th-14, Th-R and Psf-3. Present investigation suggests the effect of bioagents colonized on the dramatic increase in earthworm’s population (young and adult), earthworm’s body length, sorghum plant biomass yield and reduction in stalk rot disease severity. Our experiments have shown that bioagents colonized vermicompost have considerable potential not only improving plant growth, suppression of stalk rot disease severity significantly but also increasing soil earthworms when used as pre-plant soil amendment.