Control of proton efflux from corn root tissue by an injury-sensing mechanism
1982
Chastain, C.J. (Illinois Univ., Urbana (Netherlands). Dept. of Botany) | Hanson, J.B.
The electronic H('+) efflux of washed corn root tissue is completely inhibited by bried exposure to ice temperatures, hypertonicity and gentle rubbing. Fusicoccin (FC) will partially restore the H('+) pumping, and an uncoupler will nullify the effect of FC. Oligomycin and ethidium bromide, known to block H('+) transport by mitochondrial ATPase, will very rapidly block H('+) efflux from roots and FC will partially restore it. The previously reported inhibition of H('+) efflux by protein synthesis inhibitors occurs before amino acid incorporation is much affected. Use of the pH indicator dye, bromocresol purple, shows that cutting injury leads to H('+) influx in cells around the wound surface; cold shock leads to a general H('+) influx. It is proposed that external and internal injuries signal activation of an endogenous control mechanism which blocks the H('+) channel of the plasmalemma ATPase and that FC acts to bypass the block.
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