Effect of low-frequency magnetic field on esterase activity and pH changesnear the wheat germ during imbibition of seeds

The role of nonsteady phenomena determined by a low velocity of ion movemen ts in a weak external field is considered in relation to their possible non linear effects on processes occurring in boundary layers near the membrane, particularly, on the release of membrane-bound proteins and pH value. It i s shown that a shea-term treatment of wheat seeds with low-frequency magnet ic field at the stage of esterase activation during seed swelling enhances the activation of esterases; the effect observed at final stages of activat ion depends on the time after the treatment with electromagnetic field. Tre atment of seeds with electromagnetic field at this stage changed qualitativ ely the time course of the release of reaction products into the medium: th e reaction rate increased initially and then decreased below the control le vel. At earlier stages of swelling in treated seeds and at all stages in co ntrol seeds, the time course of the product release was linear. The retarda tion of the release of the reaction products at terminal stages of esterase activation is presumably related to the release of proteins and their comp lexes under the action of electromagnetic field and the resulting restorati on of the barrier properties of membranes. Treatment with electromagnetic f ield also caused a noticeable acceleration of proton flow form the medium, which was judged from pH changes in the bulk medium and in the vicinity of germ surface. The difference between the treated and control samples after 23-24 h of imbibition became statistically significant and was as high as 0 .4 pH units. By taking into account the nonsteady phenomena occurring upon action of low-frequency electromagnetic field, it is possible to explain un usual dependences of biological effects on the amplitude of the electromagn etic field, including the atypical enhancement of these effects by the acti on of weak low-frequency fields.