Danos oxidativos associados a estresses abióticos durante a germinação e desenvolvimento inicial de plântulas de milho

Abstract

Soil contamination by salinity and heavy metals are factors that limit agricultural production, affecting seed germination and initial seedling development. Purple corn stands out as an important source of natural pigments, which can be used for various industrial purposes. In view of the above, the objective of this study was to evaluate the effect of oxidative damage associated with abiotic stress during germination and the initial development of purple corn seedlings. The experiment was conducted at the Universidade Federal Rural de Pernambuco, Serra Talhada Academic Unit. For each experiment, the design used was the entirely randomized 5x2 factor scheme (concentration x temperature), with four repetitions of 50 seeds (germination test), four repetitions of 20 seeds (seedling length and dry mass test) and three repetitions of five normal seedlings, from the germination test (indicators of oxidative damage). The parameters evaluated were germination percentage, length and total dry mass of the aerial part, root system and indicators of oxidative damage (total chlorophylls, a, b, total carotenoids and lipid peroxidation) in the seedling phase. All analyses were performed using the statistical software SISVAR v. 5.6 and the Sigma Plot 10.0 software was used to produce the graphs. The increase in saline concentrations affected germination, growth parameters (length and dry mass) and indicators of oxidative damage (total chlorophylls, a, b, total carotenoids and lipid peroxidation) of purple corn seedlings. The association of the different saline concentrations with the temperature of 30ºC provided superior growth parameters, even in conditions of saline stress. The use of different aluminum concentrations did not interfere in the germination percentage of purple corn seeds, while the growth parameters (length and dry mass accumulation) and the indicators of oxidative damage (total chlorophylls, a, b, total carotenoids and lipid peroxidation) of purple corn seedlings were reduced with the increase in aluminum concentrations. The association of the different aluminum concentrations with a temperature of 25ºC indicated that the growth of the aerial part was less affected with the increase in concentrations. A temperature of 30ºC resulted in a greater accumulation of total dry mass, of the aerial part and of the root system of purple corn seedlings. In view of the above, germination, initial seedling development and indicators of oxidative damage subjected to sodium chloride concentrations and initial seedling development and indicators of oxidative damage subjected to aluminum concentrations are efficient to evaluate the physiological performance of purple corn seedlings.