EFFECTS OF METHYLXANTHINES ON SEISMONASTIC REACTION, PROTON FLUX, MEMBRANE-POTENTIAL, RESPIRATION AND CALCIUM-UPTAKE IN MOTOR CELLS OF MIMOSA-PUDICA PULVINUS
G. Roblin et al., EFFECTS OF METHYLXANTHINES ON SEISMONASTIC REACTION, PROTON FLUX, MEMBRANE-POTENTIAL, RESPIRATION AND CALCIUM-UPTAKE IN MOTOR CELLS OF MIMOSA-PUDICA PULVINUS, Journal of plant physiology, 142(2), 1993, pp. 197-202
Methylxanthines (theophylline, aminophylline, caffeine) inhibit the se
ismonastic reaction of primary pulvini of Mimosa pudica leaves, showin
g that these compounds act on rapid turgor variations and the concomit
ant ion migrations. Compared with theophylline, aminophylline is more
effective and caffeine is less effective in triggering the inhibitory
effect. These compounds alter H+-ATPase activity as a rapid dose-depen
dent proton influx was noted about 4 min after application, indicating
that an early impact may be at the plasmalemma. However, they have al
most no effect on the motor cell membrane potential. Moreover, the com
pounds hinder the calcium transport. Not all of these inhibitory effec
ts are mediated through an action on general cell metabolism since res
piration was not affected even by rather long treatment (about 2 h).