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Weak Mechanical Stimulation Causes Hyperpolarisation in Root Cells of Lepidium
Author(s) -
Monshausen Gabriele B.,
Sievers A.
Publication year - 1998
Publication title -
botanica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0932-8629
DOI - 10.1111/j.1438-8677.1998.tb00713.x
Subject(s) - elongation , biophysics , membrane potential , stimulation , chemistry , lepidium sativum , anatomy , materials science , biology , botany , neuroscience , ultimate tensile strength , composite material , germination
In order to study the effect of mechanical stimulation on the membrane potential (E m ) of roots of Lepidium sativum L., the roots were subjected to pulses of perfusion medium expelled from a micropipette positioned 1 mm from the root surface at the level of the elongation zone. On the opposite side of the root, a microelectrode was inserted into rhizodermal or cortical cells of the elongation zone to record the membrane potential during such a pulse. A medium pulse elicited a fast transient hyperpolarisation of up to −38 mV, reaching a peak approx. 1 min after the start of a pulse. Both degassing the medium and increasing the buffer strength had no effect on the magnitude of the pulse‐induced hyperpolarisation. Covering the roots with Parafilm, and thereby preventing an exchange of medium in the vicinity of the root during a pulse, while still providing a mechanical stimulus, also did not abolish the response. We conclude that Lepidium roots are capable of perceiving extremely weak mechanical stimuli (less than 1 mN) which induce rapid transient hyperpolarisations of the plasma membrane.