On the Colour of Leaves of Plants and their Autumnal Changes

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                                Ten per cent solutions were prepared of most of the substances 
employed and in some few cases five per cent solutions were 
used and of each of these a small quantity, usually a 
few drops only were added at one time.
It was found, that the carbonates of ammonium,
sodium and potassium all at first increased the depth of 
the green, but this after some hours changed to olive green 
and even brown; they also exerted a marked solvent action 
in the chlorophyll itself:-
That a solution of soap intensified the colour greatly,
the brilliant green hue being retained for some days:-
That phosphate of sodium and chloride of sodium at 
first increased the green colour to a small extent only, but 
after a time it became dark brown; both solutions exerted 
a slight solvent action.
The organic acids on the contrary, as citric and especially 
tartaric acid, destroyed the green colour quickly, turning 
it from green to a light yellowish brown. They also exhibi=
ted considerable bleaching properties, but they showed no 
solvent action on the chlorophyll as did the alkaline 
Bitartrate of potassium changed the bright grass 
green to dark olive, but it exerted no solvent action.
Olive oil quickly dissolved the chlorophyll and turned 
it to amber or olive brown.
Accompanying the change of colour, due to the action 
of the acids, a precipitation occurs of a granular matter,
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Manuscript details

Arthur Hill Hassall
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Cite as

On the Colour of Leaves of Plants and their Autumnal Changes, 1892. From The Royal Society, AP/69/1



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