Plants’ Senses.

Star (Christchurch), Volume LXVI, Issue 20509, 10 January 1935, Page 8

Plants’ Senses.

Nature Notes

By

James Drummond,

F.L.S., F.Z.S.

PLANT’S TENDRIL has responded to the light touch of a piece of thread Stamens have responded to the touch of an insect’s legs. Leaves of the sensitive plant have responded to a sudden jar.

Plants have no eyes to see with, no ears to hear with, no nervous system, no musclecells. like animals. Yet there may be sensitiveness without sense organs and without nerve-cells, and there is movement without muscle-cells. Some plants are irritable. Delicate instruments have demonstrated that even a tree responds to the shade of a passing cloud. Plants certainly are sensitive to outside influences. They respond so readily, unmistakably and surprisingly that it is not going too far to speak of plants’ senses. Part of a plant may receive a message and pass it on to another part, and the whole plant springs into activity. The rate at which the message travels is much slower than in animals, using this word for all members of the animal kingdom, not for mammals only. A message rushes from the tips of a person's fingers to the brain in the hundredth part of a second. A wounded tendril sends its message at the rate of half an inch a second. A message that a tendril has been merely touched is sent at the rate of about one hundred and fiftieth of an inch in a second. The mawhai. New Zealand’s only member of the melon, pumpkin and cucumber family, is a climber, with tendrils so sensitive that their tips completely encircle an object a few minutes after a tendril has touched it. The faculty to curve-is communicated by the tips to the rest of a tendril, which then takes on the corkscrew form, one of Nature’s most astonishing contrivances. One part of the tendril coils from right to left, the other from left to right. This is a distinct advantage over the continuous spiral. It gives sufficient play to avoid strain on the twisting during a strong wind.