C. Andersonbernadas et al., RHYTHMIC NATURE OF THIGMOMORPHOGENESIS AND THERMAL-STRESS OF PHASEOLUS-VULGARIS L SHOOTS, Journal of plant physiology, 151(5), 1997, pp. 575-580
Effects of mechanical stress (or stimulus) on the length of Phaseolus
vulgaris L. (cv. Kentucky Wonder pole bean) shoots displayed a 24 h rh
ythm, relative to the time of day that plants were subjected to stress
. Shoots were shorter when subjected to mechanical stress near the end
of the dark span and the beginning of the light span. Mechanical stre
ss also affected the ultradian shoot movement rhythm (circumnutation)
of P. vulgaris. Generally, horizontal shoot movements (monitored at 10
min intervals) displayed a mean period of about 1.4 h. After a brief
exposure to mechanical stress (e.g., 10 rubs), the mean period increas
ed to about 2.0 h. Effects of thermal stress were similar to those of
mechanical stress. When plants were exposed briefly (5 min) to either
high (45 degrees C) or low (0 degrees C) temperatures, the period incr
eased to about 2.1 h. Regardless of whether plants were subjected to m
echanical or cold stress, ultradian periodicity was restored to in ori
ginal period length after one cycle.