Experimental Separation of Sensory and Motor Functions in Pea Tendrils

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Science  14 Jan 1977:
Vol. 195, Issue 4274, pp. 191-192
DOI: 10.1126/science.195.4274.191


When illuminated pea tendrils from light-grown plants are rubbed on their abaxial side, they rapidly coil in a spiral fashion. If similar tendrils are held in the dark for 3 days and then rubbed, however, they will not coil until they are subsequently illuminated. They can remain uncoiled in the dark for as long as 2 hours after stimulation, and will still coil immediately when they are illuminated. Tendrils that are rubbed and held at 25°C will coil, but those treated at 5° or 10°C will not. However, tendrils rubbed at 25°C and kept from coiling for an hour at 5°C, will immediately coil when restored to the higher temperature. These observations are interpreted to imply separation of sensory and motor functions.