Re the query by Mark Spiro as to whether cytokinins can be added to
plants using lanolin pastes, the answer is yes. For example, a 0.1%
(w/w) BAP in lanolin paste can be prepared by first dissolving the
appropriate weight of BAP in a minimum volume of 0.5 M KOH and then
stirring this into the appropriate weight of warm, fluid hydrous lanolin
(i.e. you need 10 mg BAP for 10 g lanolin). A reference for this is
Clifford et al. (1992) Journal of Agricultural Science, Cambridge 119, 71-
78. You then use the BAP/lanolin paste in much the same way as you
would with an IAA/lanolin paste as a means of applying the hormone to
a selected region of the plant so there there is a gradual supply over a
prolonged period.
One thing to add re this application method is that you really have no
idea as to the actual concentration being added as you would with
applying say a 10-5 M BAP aqueous solution. It's the same argument
when using say 0.1% IAA in lanolin paste. In fact, I can tell you that a
0.01% IAA in lanolin paste behaves no differently than a 0.1% IAA in
lanolin paste in relation to a promotory effect on elongation of
Phaseolus hypocotyl lengths depleted of their endogenous auxin. This
suggests that the application method has its limitations - all you can do
is define the amount added in terms of how the lanolin paste was made
on a weight to weight basis.
Best wishes, Paul Clifford
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