Herbicide-induced hormesis and its effect on crop development

Resumo

The beneficial effect of growth stimulation caused by low doses of a toxic product such as an herbicide, is due to the phenomenon known as hormesis. Plants affected by this phenomenon show changes in their metabolism and, as a result, are able to increase nutrient absorption and biomass accumulation. Various herbicides have been developed as growth regulators, proving the hormesis hypothesis. The most notable example is the product 2,4-D, originally developed as auxin. This phenomenon can bring benefits for crops, such as increased yield. However, for the technique to be applied in practice, information is still needed to support its potential application in agriculture. The aim of this review was to define the state of the art and measure the effect of the hormesis phenomenon of herbicides in agriculture. To carry out a bibliographical review using the following databases: SciELO, Scopus, Web of Science, Redalyc, EBSCO, and DOAJ. The quality of the studies was assessed using eligibility, inclusion and exclusion criteria, employing the following indexing terms: dichlorophenoxyacetic acid, herbicide subdose, herbicide toxicity, and growth regulator. Based on a summary of the studies identified via electronic or manual searches relating to the phenomenon of hormesis, it was found that the literature on the subject remains ambiguous, with no consensus regarding the real effects of the phenomenon on crop performance. This article further argues that the magnitude of the hormetic effect on crops depends on several factors, such as the subdose, the age of the plant, and other conditions.