Leek leaf discs (1.6 cm diameter) were taken from
inner layers of leek plants using a punch and were placed
in glass Petri dishes (9 cm diameter).All essential oils
and compounds were suspended in distilled water plus
Triton X-100 (0.5%) as wetting agent. Because of the
poor water solubilityof 1,8-cineole an adequate amount
of ethanol was added to its suspension.The Petri dishes
with the leaf discs were sprayed by means of Potter
SprayTow er (Burkard Manufacturing Co Ltd., Rickmansworth,
England) at constant air pressure with
dilution quantities at 1%, 0.1% or 0.01% concentration
to achieve an exact wet deposit of 0.1, 0.01 or 0.001 ml oil
or compound per cm2 leaf surface