Re: What is the effect of a changing magnetic polarity on aquatic plant membran

Dear Bill:

The effects of magnetism on plants is contentious. There are as many studies reporting negative findings as positive. Some of the inconsistencies have arisen because scientists have used such a diversity of experimental protocols. Some have used strong magnets, others weak. Some have been careful to take into account ion effects from the magnet itself: others haven’t. Some have used stationary magnets; others moving magnets. Some have studied the effects of reduced geomagnetic fields on plants; others enhanced.

Some have argued that electromagnetic frequency is a more important experimental variable than absolute strength. Of course, all of this research was done on different species at different stages of development...it is quite possible that a seed may respond much differently than a fully hydrated seedling.

Due to this contentious history, you probably won’t find much mention of magnetism and plants in textbooks and databases (moreover, much of the post-WWII research is published in Russian). In short, I don't know the answer to your question, particularly as you are vague about the details of your proposed protocol. My hunch is that you will find no effect in most cases, but let me point you in the direction of three old and dusty articles that may inspire you:

Palmer JD (1963) Organismic spatial response in very weak spatial magnetic
fields.   Nature 198: 1061-1062

Brown FA, Chow CS (1975) Non-equivalence fro bean seeds of clockwise and
counterclockwise magnetic motion: a novel terrestrial adaptation? Biol 
Bulletin
148:370-379

Jones, RL (1960) Response of growing plants to a uniform daily rotation.
Nature
185:775