We studied the effects of weak and extremely-low-frequency(ELF) magnetic fields (MFs) on the growth and germination of spruce seedlings(Picea abies (L.) Karsten) that were exposed simultaneously to differentpH values. The experiments showed that a weak, sinusoidal magnetic field(50 Hz, 26 and 105 microT, stimulation 12 h/day), which was computer controlled and generated by a system of Helmholtz-like coils, slightly reduced the length and delayed germination at low pH values. 26 microT 50 Hz MF slightly reduced the length at pH 2, delayed germination at pH 2 and 3, whereas at pH 6 and 7 there were no effects or they were even stimulatory. At a higher magnetic flux density (105 microT) the length, fresh weight and germination were reduced mostly at pH 2 and 3 and with a higher statistical significance than at 26 microT. Germination was influenced during the first days of germination and later on the effect diminished rapidly. 10 microT and 46 Hz MF stimulated only the length of the seedlings. This phenomenon corresponds with the observations made by some other authors, namely that biological systems during various phases of intensive growth and/or insuboptimal environmental conditions (physiological stress) are prone to exhibit greater sensitivity to ELF fields.

The following graph represents the effects of magnetic field 105 microT, 50 Hz on the average germination% of spruce seeds (Picea abies) grown at low pH (pH 2 and 3) and at middle pH value(pH 7) watered with distilled water on day 1 and on day 3.