Extremely low frequency non-uniform magnetic fields improve tomato seed germination and early seedling growth

The influence of pre-sowing magnetic field treatments on tomato (cv. Lignon) seed germination and seedling growth under laboratory conditions and emergence and plant growth parameters under greenhouse conditions were studied. Seeds were exposed to 60 Hz full-wave rectified sinusoidal non-urn form magnetic fields (MFs) induced by an electromagnet at 80, 120, 160 and 200 mT(rms) for 1, 3, 5, 10, 15 and 20 min. Under laboratory conditions, various combinations of magnetic field strength and exposure time significantly improved seed performance in terms of reduction of time required for the first seeds to complete germination, time to reach 50% germination, time between 10 and 90% germination with increasing germination rate, and increased germination percentage at 4 and 7 days, seedling shoot and root length compared to the untreated control seeds. The combinations 160 mT for 1min and 200 mT for 1 min gave the best results. In soil, exposure of seeds to these two magnetic fields significantly increased emergence index, percent emergence. shoot and shoot length, shoot and root dry weights and leaf area of 28-day-old seedlings under greenhouse conditions compared to control seedlings. Ore-sowing magnetic treatments therefore have the potential to enhance tomato seed germination and early seedling growth.