Atividade alelopática de extratos de plantas cultivadas sob estresse salino e aplicação de metabólitos secundários como indutor de germinação

Abstract

The production of metabolites with allelopathic action is a mechanism of adaptation of plants in which it provides the greatest development of the plant itself or limits the growth of the other plants around it, thus favoring the establishment of culture. The production of these compounds can be the basis for the production of inhibitors and growth stimulant, however, with varying levels due to the influence of the environmental condition. In the Northeast region, the increase in temperature and the reduction in rainfall are the main abiotic changes expected with the impact of climate change that may occur, so these conditions are factors that can contribute to an increase in the percentage of areas affected by water problems. salinization. Therefore, the salt stress that tends to intensify, and, consequently, change the adaptation mechanisms of plants to achieve a new homeostatic balance may trigger changes in intraspecific and interspecific relationships, especially in species with allelopathic potential. Allelopathic compounds can have reduced production, as the plant can allocate more energy to activate other adaptation mechanisms or can increase the production of these compounds to limit the growth of others around them, therefore, they can decrease competitiveness and improve production mineral and water resources. In this context, the present study aimed to evaluate the effects of different salt concentrations on the initial growth and biomass production of two sorghum cultivars and a weed (Cyperus rotundus); as a second objective, we sought to evaluate the allelopathic responses of the aqueous extracts of these plants conducted in saline conditions on the germination of lettuce and to identify the secondary metabolites involved. After stress was identified on the rutin content and this metabolite could be the answer to the allelopathic effect, exogenous rutin was applied, through conditioning and seed coating, on the germination of sorghum under salt stress conditions. In both extracts, of sorghum and nutsedge cultivars grown under saline stress, they caused degradative effects on the rate of germination speed, germination, first count of lettuce seedlings. Routine application attenuated the degradative effects of salinity on the biomass germination, germination speed index, lengthy germination of the aerial part and root being more promising in conditioning than in seed coating.