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In order to analyze the treatment of seeds with homogeneous static magnetic field on the water adsorption process, an experimental-theoretical study of hygroscopic equilibrium in maize seeds (Zea mays L. cv. ICAV305) was carried out. Four treatments with magnetic induction of 80.0, 120.0, 160.0, and 200.0 mT were applied for 10 min, and there was a control group without treatment. The doses were selected because they showed a decrease in mean germination time. Treated seeds were subjected to an environment with a stable temperature of 30.0 °C ± 0.1 °C and atmospheres of different relative humidity (h), using eight salt solutions saturated with water activity between 0.216 and 0.970. Curves were adjusted using the D'Arcy-Watt and modified Oswin models. It was found that the magnetic treatment of seeds affects adsorption, and the 200 mT-10 min one was the most significant in affecting the mechanisms of adsorption of water, and increasing the number of adsorption sites connected to weak binds with D'Arcy-Watt's adjustment. Using the Oswin model for simulation, we verified that the magnetic stimulus affected the enthalpy of adsorption and the mechanism of incorporation of water vapor molecules to the structure of seminal cover. These results show that the magnetic pre-treatment of seeds has an effect on a seed's specific biophysical and physiological processes in the early stages of germination. Bioelectromagnetics. 39:343-351, 2018. © 2018 Wiley Periodicals, Inc.

Gibberellic acid is a phytohormone that triggers the germination of seeds in a state of dormancy. Through the quantification of this hormone, the physiological condition of seeds of economic importance can be studded. In this work we validated a High-Performance Liquid Chromatography method to quantify gibberellic acid in germinated maize (Zea mays L.) seeds. Chromatographic conditions included the use of a C-18 reversed-phase column, acetonitrile-formic acid (1 : 9 %) as the mobile phase, flow of 0.5 mL·min-1, and detection at 195 nm. We evaluated our method for seven analytical parameters. The method was linear for gibberellic acid concentrations from1.0 mg·kg-1 to 50.0 mg·kg-1. The method’s limits were 0.3 mg·kg-1 and1.0 mg·kg-1 for detection and quantification, respectively. The method was highly precise; we obtained variable but low relative standard deviations (2.62 % - 12.66 %) for the studied gibberellic acid concentrations. We assessed accuracy through recovery percentages, ranging from 52.85 % - 63.68 %, for three gibberellic acid concentrations. We conclude that our analytical method can be used to measure gibberellic acid during the early stages of maize germination. In addition, the method could be used for the analysis of other types of plant matrices.

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The effect of homogeneous static magnetic stimulation on Zea mays L. (maize) seeds and its potential utility as a tool in biotechnological development for the improvement of maize seeds was studied. The values of magnetic flux density that influenced the biological development of some plant species of the Poaceae family were determined from a literature review. ICA V-305 variety corn seeds were exposed to seven values of magnetic flux density between 50.0 mT and 250.0 mT, with homogeneity of 98.4% and at (1.0, 3.0, 5.0 and 7.0) min exposure times. The mean germination time (MGT), index of germination speed (VGer) and germination rate (Gmax) were evaluated as responses. The magnetic flux density of 50.0 mT with a one-minute exposure time recorded the largest reduction (12.4%) in the MGT while the germination rate for the same treatment increased by 17.4% with respect to the control. No significant effects of the magnetic treatment were recorded for the Gmáx . The magnetic treatment of seeds with homogeneous static fields does not have as favourable a response as the treatments with fields with magnetic gradients, that is to say, using toroidal magnets.