Hormesis Effect of Dichlorophenoxy Acetic Acid Sub-Doses and Mepiquat Chloride on Cotton Plant

Abstract

The aim of this study was to evaluate the hormesis effect of sub-doses of dichlorophenoxy acetic acid herbicide and the plant growth regulator mepiquat chloride on the vegetative and productive characteristics of two cotton cultivars (FMT 701 and Fibermax 966). The experiment was conducted from November 2013 to May 2014. The experimental design was a randomized block in a factorial scheme 6 x 2 x 2, with four replications, totaling 96 installments with 24 treatments: the witness and five sub-doses of the herbicide 2,4-D: 0.68, 1.36, 2.04, 2.72 and 3.40 g equivalent acid (e.a) per ha, with and without application of mepiquat chloride at a dose of 200 mL ha-1 in the cotton cultivars FMT 701 and Fibermax 966. The sub-doses applied were 2,4-D at 45 days after the emergence of the plant (DAE), and the growth regulator was applied at 70 DAE. It was found that the use of the growth regulator (mepiquat chloride) at a dose of 200 mL ha-1 was effective in controlling plant development relative to its variable height. The application of sub-doses of 2,4-D up to 1.75 g e.a ha-1 provides increased seed cotton productivity FMT 701 and Fibermax 966). The cultivar FMT 701 got greater plant height, stem diameter, number of reproductive branches, bolls per plant and seed cotton productivity compared to the cultivar Fibermax 966.

Different types of herbicides in inducing the hormetic effect on soybean culture

“…Deste modo, os herbicidas auxínicos podem promover o crescimento de plantas em concentrações não tóxicas imitando a auxina, hormônio do crescimento (ALLENDER et al, 1997;CEDERGREEN et al, 2007;MOTA, 2015;MARQUES, 2019). Herbicidas à base de auxinas são modelos bem conhecidos de produtos químicos que promovem o desenvolvimento das plantas em concentrações não tóxicas, mimetizando a auxina, podendo se tornar letais a alguns vegetais quando aplicado em doses mais elevadas (AMÉRICO; PINHEIRO;FURLANI, 2017).…”

Hormesis effect of 2,4-D choline salt on soybean biometric variables

“…Auxin-based herbicides, such as 2,4-D, are examples of chemical products that enhance plant growth at nontoxic concentrations, but are lethal at higher doses (Americo et al, 2017). Known as a growth regulator, synthetic auxin or hormonal herbicide, 2,4-D belongs to the class of auxin-mimicking herbicides, because at low concentrations it has physiological and biochemical effects similar to those of the indole-3-acetic acid (IAA), the main natural auxin present in plants (Vanneste and Friml, 2009).…”

Hormesis of 2,4-D Choline Salt in Biometric Aspects of Cotton

“…Auxin-based herbicides, such as 2,4-D, are examples of chemicals that enhance growth at nontoxic concentrations but are lethal at higher rates (Americo et al, 2017). Thus, such responses may be expected with increased auxins production and activity and may interfere with the plants' growth and development (Tavares et al, 2017).…”