Efeito do fungicida estrobilurina no crescimento inicial no feijoeiro
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Data
2024-02-28
Autores
Rocha, Ana Caroline Pariz
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Universidade Federal do Espírito Santo
Resumo
Agricultural pesticides, especially strobilurin fungicides, are essential for increasing agricultural productivity but can also negatively affect metabolism and morphophysiological parameters, resulting in the cessation of growth of plants of agronomic interest. Thus, the objective of the research was to evaluate the effect of a strobilurin fungicide containing the active ingredient pyraclostrobin (PCL) on the morphophysiological components of Phaseolus vulgaris L. and to investigate whether the residual effect remains after planting the seedlings. Bean seeds were pre-soaked for 5 minutes in distilled water followed by soaking in different concentrations of PCL (0, 112, 450, and 1800 mg/L) for 10 and 30 minutes, and placed in germiest paper rolls and germinated for 8 days in a growth chamber at 25 °C. The percentage of germination, growth, biomass, anatomical, and physiological were evaluated. Thereafter, seedlings subjected to treatments with 0, 450, and 1800 mg/L of PCL were transferred to tubes and grown in a greenhouse for 15 days after previous exposure to the strobilurin fungicide to assess whether the residual effect remained. The research proved that PCL interference was proportional to the concentration and soaking time of the seeds. Interference was observed in the percentage of germinated seeds in the first count, normal and abnormal seedlings, and dead seeds, for both imbibition times. There was a decrease in seedling growth, as well as in the diameter of the xylem of the leaves, stem, and root, resulting in a lower accumulation of biomass. Furthermore, as the concentrations of the PCL solutions increased, at both times, a reduction in the clr content was observed in a clr., total clr and car., resulting in the reduced photosynthetic performance of FSII, with lower values of PIABS, PITOTAL e φP0. However, the seeds soaked in 0 and 112 mg/L of PCL showed a larger diameter of the xylem vessels, which allowed an increase in seedling growth. In addition, these concentrations contributed to a greater effective photochemical activity of FSII. The negative effect of PCL was maintained for chlorophyll a transient fluorescence, plant growth, and photosynthetic pigment content. PCL interfered with the oxygen evolution complex (K-band) and the energetic connectivity between the FSII subunits (Lband), decreasing the values of ΦFSII, ETR and FV/FM. Additionally, the fraction of NQB reducing centers showed a time and concentration-dependent increase. The research confirmed that the responses induced by PCL vary according to the concentration and imbibition time. It was analyzed that lower doses of PCL contribute to the germination, growth, anatomy, and physiology of bean seedlings. Finally, the residual effect of PCL on the morphophysiological components of the plant was maintained
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Anatomia vegetal , Chlorophyll a fluorescence , Phaseolus vulgaris