RESUMO
Plant endogenous mechanisms are not always sufficient enough to mitigate drought stress, therefore, the exogenous application of elicitors, such as salicylic acid, is necessary. In this study, we assessed the mitigating action of salicylic acid (SA) in cowpea genotypes under drought conditions. An experiment was conducted with two cowpea genotypes and six treatments of drought stress and salicylic acid (T1 = Control, T2 = drought stress (stress), T3 = stress + 0.1 mM of SA, T4 = stress + 0.5 mM of SA, T5 = stress + 1.0 mM of SA, and T6 = stress + 2.0 mM of SA). Plants were evaluated in areas of leaf area, stomatal conductance, photosynthesis, proline content, the activity of antioxidant enzymes, and dry grain production. Drought stress reduces the leaf area, stomatal conductance, photosynthesis, and, consequently, the production of both cowpea genotypes. The growth and production of the BRS Paraguaçu genotype outcompetes the Pingo de Ouro-1-2 genotype, regardless of the stress conditions. The exogenous application of 0.5 mM salicylic acid to cowpea leaves increases SOD activity, decreases CAT activity, and improves the production of both genotypes. The application of 0.5 mM of salicylic acid mitigates drought stress in the cowpea genotype, and the BRS Paraguaçu genotype is more tolerant to drought stress.
RESUMO
The biosynthesis of phenolic compounds might be influenced by environmental factors, such as solar radiation, temperature and relative air humidity, and production system. Some components of the production system, particularly the trellis system and rootstock, might change the phenolic composition of grapes due to microclimate of the cultivation region. In this study, the phenolic profile of Chenin Blanc grapes was characterized with different trellis systems and rootstocks in two consecutive production cycles by using high-performance liquid chromatography under tropical semi-arid conditions. In the second production cycle (Jan-May/2016), accumulation of (-) - epicatechin gallate and (-) - epigallocatechin gallate was higher when vigorous rootstocks were trellised to the lyre system, whereas the lyre system associated to rootstock SO4 resulted in higher rutin accumulation in the same cycle. There was little influence of the factors studied on trans-resveratrol and piceatannol accumulation. However, a higher accumulation of piceatannol was observed in the second productive cycle compared to cis-resveratrol and trans-resveratrol. This study highlights that accumulation of phenolic compounds is influenced not only by environmental factors typical of the production year season, but also by the trellis system and rootstock adopted. The identification of phenolic compounds in the accumulation stimulated by the combination of trellis system, rootstock, and production season allows to differentiate grape quality and add value to products derived from such combination in a tropical semi-arid region.
Assuntos
Vitis/química , Compostos Fenólicos , 24444 , Estilbenos , Resveratrol , Sucos de Frutas e Vegetais , VinhoRESUMO
The biosynthesis of phenolic compounds might be influenced by environmental factors, such as solar radiation, temperature and relative air humidity, and production system. Some components of the production system, particularly the trellis system and rootstock, might change the phenolic composition of grapes due to microclimate of the cultivation region. In this study, the phenolic profile of Chenin Blanc grapes was characterized with different trellis systems and rootstocks in two consecutive production cycles by using high-performance liquid chromatography under tropical semi-arid conditions. In the second production cycle (Jan-May/2016), accumulation of (-) - epicatechin gallate and (-) - epigallocatechin gallate was higher when vigorous rootstocks were trellised to the lyre system, whereas the lyre system associated to rootstock SO4 resulted in higher rutin accumulation in the same cycle. There was little influence of the factors studied on trans-resveratrol and piceatannol accumulation. However, a higher accumulation of piceatannol was observed in the second productive cycle compared to cis-resveratrol and trans-resveratrol. This study highlights that accumulation of phenolic compounds is influenced not only by environmental factors typical of the production year season, but also by the trellis system and rootstock adopted. The identification of phenolic compounds in the accumulation stimulated by the combination of trellis system, rootstock, and production season allows to differentiate grape quality and add value to products derived from such combination in a tropical semi-arid region.(AU)