Magnetic fields had previously been observed in other plants; algae in one study, bean plants in another. The previous magnetometers, called SQUIDs, are large and run at very cool temperatures, and the team needed something more convenient for their use. Different actions on or by a plant can elicit the fields—from being wounded to trying to snap at food within its reach, as was the case with the flytrap. The magnetic field doesn’t correspond with the act itself but the action potential that precipitates the plant’s next move.I've been puzzled by the missing square in the otherwise orthogonal pattern of inputs and outputs. = = = = = START REPRINT: Nature uses magnetic and static fields and ion currents ALMOST universally, but there are some exceptions. Why? Static fields are used for internal communication EVERYWHERE. Inside a cell, between cells, in the nervous system, inside muscles, EVERYWHERE. Static fields are used for external communication more narrowly, but one of the narrow uses is common. Plants communicate with pollinating insects by fields, telling the bugs which flowers are ready for pollination and which are used up. Mud-dwelling fish use static fields for radio communication, in FM Stereo. Static sensors are part of the communication systems in above paragraph, and more broadly used by just about everything to detect nearby objects. (Even dull humans use the hairs on our arms for this purpose!) Static fields are used directly for motion in two ways, one of which is nearly universal. Cells drive their flagella with a synchronous motor, using phased variation of static fields. Spiders alter their charge to move away from walls and toward plants when hanging from a silk fiber. = = = = = Ion currents are also EVERYWHERE for internal communication. The nervous system is all about ion currents. Bacteria use ion currents to communicate via miniature wires, and some plants send currents through fungal wires. Ion currents are sensory as part of the wire systems above. Ion currents are NOT used for motion as such. Currents are a vital part of muscle action, but the current isn't what moves the animal. = = = = = Magnetic fields are used by EVERYONE for sensing 3d position, but NOT used for the other purposes. It's possible that bees use magnetic motion for communication in their waggle dance, but this doesn't seem to be established. = = = = =
|Static field||Ion current||Magnetic field|
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