Sm. Ayling et al., THE CYTOPLASMIC STREAMING RESPONSE OF TOMATO ROOT HAIRS TO AUXIN - OBSERVATIONS OF CYTOSOLIC CALCIUM LEVELS, Journal of plant physiology, 143(2), 1994, pp. 184-188
Cytoplasmic streaming velocity in tomato root hairs was strongly influ
enced by the addition of IAA to the bathing medium. Concentrations of
IAA above 10(-6) M were inhibitory, while concentrations between 10(-7
) and 10(-8) M stimulated streaming within 1-2 min. The transplasmamem
brane electrical potential difference was rapidly depolarised by IAA.
Measurements of cytoplasmic calcium concentrations, using the fluoresc
ent dyes fura-2 and indo-1, indicated that in some, but by no means al
l, cells auxin application was followed by a small slow increase in [C
a2+](cyt). We were unable to detect changes in [Ca2+](cyt) as rapid as
those in cytoplasmic streaming or membrane potential. The experiments
reported also illustrate some of the problems of using the dyes fura-
2 and indo-1.