As part of a continued effort
to understand the mechanism underlying smoke-stimulated seed germination,
the effect of two nitric oxide (NO) donors N-tert-butyl-α-phenylnitrone
(PBN) and sodium nitroprusside (SNP) on the germination of Grand Rapids lettuce
seeds were investigated. Seeds were treated with solutions of PBN and SNP
at concentrations from 10–1 000µm, and with a combination of 1:1 000 aqueous
smoke solution and the NO specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
potassium (c-PTIO). No enhanced germination was observed with the PBN and
SNP treatments, and c-PTIO showed no inhibition of the germination stimulated
by a 1:1 000 dilution of an aqueous smoke solution. These results suggest
that factors, other than NO, are responsible for the enhanced germination
of Grand Rapids lettuce seeds by aqueous smoke solutions.

South African
Journal of Botany 2002, 69(2): 217–219