This article focuses on an adulterated chrysanthemum cut flower.  As can be seen above, the blooms are startling because of their intense blue colour.  Unfortunately, the colour is fake, having been produced by placing the cut stem in a very concentrated solution of blue dye.  The colouring agent is transported up the stem by the water conducting tubes (xylem) to the leaves, and flowers.  Since the water can exit these structures by the process of transpiration, while the dye cannot, plant tissues become darker and darker in colour until the stem is removed from the dye solution.  In some flowers, like the one shown here, the tissue at the tips of the petals absorbs the solution more poorly than the rest, and this accounts for the two-toned colouration.  The white colour of the petal tips is evidence of the fact that the flowers were originally white.  This dying process does not work on living plants, since the roots selectively absorb only the nutrients necessary for plant growth.

One of the side effects of this process is that the green leaves end up a very visually unpleasant muddy-purple colour.  For this reason, I removed all of the leaves before photographing the stem of chrysanthemums.

Like many other members of the aster family, this chrysanthemum has a composite bloom consisting of both inner disk flowers, and outer ray flowers.  Here, the outer flowers are long and tubular.  This is called the “quilled form”.  Notice in the images that follow, that the central disk flowers are much shorter in length.  Those at the very centre of the bloom have a yellow colour, and are unopened.



A closer view of the disk flowers shows that each possesses five pointed lobes.


On the other hand, the quilled ray flowers have a variety of top-ends.  Some are simply curled backwards, while others have spoon-shaped tips.



If one of the spoon-shaped petals is examined under the microscope, its jigsaw puzzle cellular structure is revealed.  (Petals of the other chrysanthemum plant examined this month show a similar cellular structure.)


Notice in the two images that follow, the opening process of the short disk flowers.


If one of the disk flowers at the centre of the disk is carefully removed from the bloom, and examined under the microscope, the dying process can be seen clearly.  In this case, the dye has advanced only to the base of the flower.


In an outer ray flower, the dye has advanced almost to the tip.  Notice that the natural yellow stripe on the flower has turned green (yellow + blue = green).


An unopened disk flower can be seen below.  Note the many pollen grains that adhere to its outer surface.


The higher magnification photomicrograph that follows shows pollen grains to be irregularly shaped and translucent.


Pollen grains are more prevalent on the inner-most disk flowers.


The disk flower shown below has been dyed right to the tip.  Note that the flower’s five lobes are clearly visible.


Finally, here are the remaining images of this altered chrysanthemum.  (The strangely coloured leaves can be seen in the second image.)



Although this dyed chrysanthemum is undeniably spectacular, there is something distinctly unreal about it!  I much prefer the natural colours of undyed flowers.


Photographic Equipment

The macro-photographs were taken with an eight megapixel Canon 20D DSLR equipped with a Canon EF 100 mm f 2.8 Macro lens which focuses to 1:1.  A Canon 250D achromatic close-up lens was used to obtain higher magnifications in several images.

The photomicrographs were taken with a Leitz SM-Pol microscope (using a dark ground condenser), and the Coolpix 4500.

A Flower Garden of Macroscopic Delights

A complete graphical index of all of my flower articles can be found here.


The Colourful World of Chemical Crystals

A complete graphical index of all of my crystal articles can be found here.

 All comments to the author Brian Johnston are welcomed.