Heat-resistant protein expression during germination of maize seeds under water stress.

Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods.

Gene expression in the lignin biosynthesis pathway during soybean seed development.

The study of gene expression in plants is fundamental, and understanding the molecular mechanisms involved in important biological processes, such as biochemical pathways or signaling that are used or manipulated in improvement programs, are key for the production of high-quality soybean seeds. Reports related to gene expression of lignin in seeds are scarce in the literature. We studied the expression of the phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase, 4-hydroxycinnamate 3-hydroxylase, and cinnamyl alcohol dehydrogenase genes involved in lignin biosynthesis during the development of soybean (Glycine max L. Merrill) seeds. As the endogenous control, the eukaryotic elongation factor 1-beta gene was used in two biological replicates performed in triplicate. Relative quantitative expression of these genes during the R4, R5, R6, and R7 development stages was analyzed. Real-time polymerase chain reaction was used for the gene expression study. The analyses were carried out in an ABI PRISM 7500 thermocycler using the comparative Ct method and SYBR Green to detect amplification. The seed samples at the R4 stage were chosen as calibrators. Increased expression of the cinnamate-4-hydroxylase and PAL genes occurred in soybean seeds at the R5 and R6 development stages. The cinnamyl alcohol dehydrogenase gene was expressed during the final development phases of soybean seeds. In low-lignin soybean cultivars, the higher expression of the PAL gene occurs at development stages R6 and R7. Activation of the genes involved in the lignin biosynthesis pathway occurs at the beginning of soybean seed development.

Condições térmicas ambientais e desempenho de aves criadas em aviários com e sem o uso de forro / Environmental thermal conditions and performance of broilers raised in aviaries with and without the use of polyethylene lining

O experimento foi realizado em delineamento inteiramente ao acaso, em esquema fatorial 2x2, para avaliar o efeito de época de ano, o tipo de forro de polietileno sobre as condições térmicas, de umidade e o desempenho de aves de corte. Foram utilizados quatro aviários, cada um dividido internamente em quatro boxes para alojar 200 aves cada. As variáveis de desempenho avaliadas foram peso vivo, ganho de peso, consumo de ração, conversão alimentar e mortalidade das aves do nascimento ao 42º dia de idade. O desempenho das aves foi melhor com aviários com forro. As condições térmicas foram melhoradas cm a utilização de forro nos aviários

This experiment was carried out in a completely randomized experimental design, factorial arrangement 2x2, to evaluate the effect of period of year and type polyethylene liming on thermal and humidity of aviaries and performance of broiler. Four aviaries were divided in four boxes to house 200 chickens each. The recorded performance traits were body weight, weight gain feed intake, feed:weght gain ratio and mortality from hatch to 42 days of age. Better thermal conditions and higher chicken performance were observed in the polyethylene liming aviaries