Close-up View of the
by Brian Johnston (Canada)
Flowering Kale, although not edible, is
grown for its ornamental, multi-coloured foliage. Even when not
“flowering” in the botanical sense, its leaves resemble a giant,
multi-petaled ruffled flower.
The plant is a member of the mustard family, (Brassicaceae). The genus Brassica is remarkable, because it
contains more important horticultural and agricultural crops than any
other genus. Turnips, cabbages, brussels sprouts, cauliflower, and
broccoli are just a few examples.
The hybrid studied in this article derives from wild Brassica oleracea, which is native
to coastal southern and western Europe, where it grows near limestone
sea cliffs. This unusual habitat is due, it is believed, to its
tolerance of lime and salt, but intolerance of competition from other
Plant breeders have, over the years, attempted to “improve” on the wild
species, by changing their growth habit, and intensifying the colour of
their leaves. Brassica
oleracea ‘Chidori White’ is one such cultivar.
Unfortunately, many, including this one, suffer from an extreme dislike
of warm weather, and so they are sold as decorative plants, solely for
the spring or fall seasons. They have the advantage of coping
with below freezing temperatures very well – in fact, the plants’
colouration is intensified after a frost!
The first image in the article shows a close-up view of the fringed
leaf colouration in ‘Chidori White’,
while the two, below, show the entire plant. I was fortunate –
only one of the plants at the greenhouse was actually in bloom on that
The base and upper portion of the plant’s flower spike can be seen
below. The central stem has many branching stalks from which the
buds, and flowers grow. Fringed leaves are concentrated near the
base of the flowering stalk.
Clusters of pale green buds are shown against a background of deeper
green leaflets in the following images.
Unlike the much larger leaves beneath the flower stalk, these are not
frilly at their edges. Notice the wide variation in the shape of
the “teeth” along the leaflet’s edge.
Buds showing just a hint of yellow beneath the enclosing sepals
(modified leaves), soon open to reveal pale yellow, four-petaled
At first, the six stamens are positioned close to one another (left
image). They soon separate (right image).
The flower’s petals do not have perfectly smooth edges, particularly at
Three images follow that show a flower’s reproductive organs.
Each light-brown anther (male pollen producing organ) is supported by a
pale green filament. At the centre of the columnar arrangement of
stamens, is a single pistil consisting of a bulbous, yellow-green
stigma (female pollen accepting organ), and its supporting darker green
Under the microscope, one of the anther lobes, and the filament are
In order to show the globular, semi-translucent cells that cover the
back surface of an anther, the dark-ground condenser was moved
Higher magnification reveals the ellipsoidal shape of individual pollen
The surface cells of the filament can be seen in the photomicrograph
At the base of the centrally located pistil is the swelling that
represents the top portion of the flower’s ovary (seed producing organ).
On the left below, is the image of the upper portion of the
pistil. At the tip is the flattened, spherical stigma. A
sturdy style supports this structure. On the right is a
photomicrograph showing the small spherical cells on the stigma’s
Beneath the flowering spike of the plant is the dome-shaped structure
formed by the rings of Kale leaves.
Notice that a relatively narrow band at the outer edge of each leaf is
ruffled. Also note the contrasting white colour of the prominent
vein structure on the back of each leaf.
The following sequence of images moves up the magnification scale in
order to show that the leaf structures are interesting at any
Each leaf is connected to the main stem by a short stalk. The two
images below show the cellular makeup of the point where leaf and stem
A lower magnification image shows different amounts of green
pigmentation, (due to chlorophyll), at various locations.
Higher magnification shows the comparison between the shape of vein
cells (left), and the cells that make up the rest of the leaf (right).
All Kale leaves have a very high water content. If a leaf is
squeezed between cover-glass and slide, tiny water droplets are
excreted that glint when illuminated.
In addition to the green–white colouration of this cultivar, many
others are available including pink and lavender. However,
whatever the colours, this plant is remarkable because of its
structurally complex, ruffled leaves.
All of 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.
Flowering Cabbage and Kale
A Flower Garden of
A complete graphical index of all
of my flower articles can be found here.
The Colourful World of
A complete graphical index of all
of my crystal articles can be found here.
Microscopy UK or their contributors.
Published in the May
2009 edition of Micscape.
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