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Physiological Studies on Pea Tendrils VIII. The Relationship of Circumnutation to Contact Coiling. — With a Description of a Laboratory Intervalometer Using Integrated Digital Circuits
Author(s) -
JAFFE M. J.
Publication year - 1972
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1972.tb03548.x
Subject(s) - tendril , pisum , biology , barrel (horology) , sativum , biophysics , turgor pressure , elongation , botany , materials science , composite material , ultimate tensile strength
The average rate of rotation of circumnutating tendrils of Pisum sativum L. ev. Alaska, was 1.57 ± 0.29 mm/min. 53% of the tendrils rotated clockwise and 47% counterclockwise. Circumnutation is apparently dependent on the maintenance of sufficient turgor as it stopped when either the roots or all the shoot appendages except the terminal tendril were excised, but resumed when the aerial wounds were covered with petroleum jelly. Both circumnutation and contact coiling were similarly retarded when the plant was cut in the middle of the top inter‐node, or by the use of either juvenile or senescent organs. As the tendril circumnutated rapidly during the sweeping portion of its circuit, it was capable of coiling at only about 57% of the rate of which it could coil if stimulated during the relatively slow moving turn, Conversely, when the tendril was mechanically stimulated to coil, its rate of circumnutation decreased markedly and remained retarded as long as the tendril continued to coil. On the basis of these observations, it is concluded that contact coiling does not seem to be simply a modified form of circumnutation, but the two modes of movement might be related through a negative feedback system.