Ov. Skobeleva et al., CELL BURST AS A MECHANISM OF PLANT-CELL INJURY .1. VISUAL OBSERVATIONAND ELECTROPHYSIOLOGICAL RECORDING OF CELL BURST INDUCED BY CA2+ DEFICIENCY, Russian journal of plant physiology, 43(4), 1996, pp. 439-447
Elongating internodal cells of Nitella syncarpa and excised root tips
of Trianea bogotensis with young root hairs were incubated in the pres
ence of 1-10 mM EDTA. The desorption of Ca2+ from the cell surface res
ulted in local ruptures of the plasmalemma and cell wall, leading to h
ydrodynamic ejections of portions of the cytoplasm (cell bursts) and s
ubsequent healing of the wounded regions. The electric parameters of t
he plasmalemma and tonoplast (potential difference, specific resistanc
e, electric-current density) continuously recorded with microelectrode
s, as well as the cessation of cyclosis in the intervals between cell
bursts, indicate an increase in the cytosolic Ca2+ level during cell b
urst. It is suggested that cell bursts are a mechanism responsible for
the injury and death of young cells under conditions of Ca2+ deficien
cy. This type of injury may occur in nature under extreme mechanical t
ension and upon enzymic or physical loosening of the cell wall. Tempor
ary elevation of the Ca2+ concentration during a cell burst is benefic
ial for wound healing; however, prolonged disturbance of Ca2+ homeosta
sis (upon recurrent bursts) may result in cell death.