A Close-up View of Two

"Parrot Tulips"

Tulipa x hybrida

Part 1

by Brian Johnston   (Canada)

The flamboyant flowers discussed in the two articles this month are certainly different than the normal garden-variety tulips found in most spring gardens.  What makes them so special to a macro-photographer, is their continued visual interest as one moves up the magnification scale.  Each bud can be considered to be a colourful sculpture, with striking structure that continues to interest the observer as he or she moves closer. 

Although tulips are often associated with the Netherlands, they are not a native Dutch flower!  About four hundred years ago Europeans first discovered tulips in Turkey.  At that time Carolus Clusius, a famous botanist, introduced the plant to the Leiden botanical gardens in Holland.  Since tulips were extremely rare, and expensive, only Kings and Emperors could afford to plant them in their gardens.

The immediate popularity of the tulip drove Clusius and other horticulturalists to produce new colour variations to satisfy the growing demand for the flowers.  Over the years, many tulip forms were produced by crossing and hybridizing techniques.  Some had frilly petals, and dramatic flame-like colourations, that later became known as “Parrot tulips”.  In the 20th century, these distinctive characteristics were found to be the symptoms of the mosaic virus which was transported to the tulip plant by a louse living on peaches and potatoes!  Today, hybrids have been developed with similar visual characteristics, but without the virus infection.

In your mind, compare normal tulips, with their single-coloured, solid, smooth petals, with the parrot variety that can be seen above, and in the two images that follow.  Parrot tulips are characterized by petals that are curled and twisted.  They also have borders that are fringed (laciniate).  Both varieties share the same characteristic lance-shaped (lanceolate), bright green leaves.

Notice the interesting, rather random colouring of individual petals in the two images below.  The colour ranges from bright red, through yellow, to almost black!

Petals have an irregular, three-dimensional fringe along their upper edge, as well as occasional projections of various sizes that emanate from their outer edges.

Viewed from behind, the smooth green stem supports the base of the flower.  In fact, the stem is the weak point of many parrot tulip varieties, as it is often too weak to support the fully open flower.  For this reason, many parrot tulips are suitable only as cut flowers.

Just how flamboyant the blooms are, can be seen below.  Notice that unlike normal tulip petals, each parrot tulip petal has its own individual characteristics.  Rotating a bloom shows a different structure with each viewpoint.

Each flower has six petals arranged with three in an inner circle, and three in an outer circle.  As a flower begins to open, the outer three petals move away first.

As we move closer to the petals of a flower, the sculptural nature of the surfaces becomes more evident.

Closer still, the petals resemble the wildest imaginings of a hallucinating modern sculptor!

If a section of one of the petals is examined under the microscope using increasing magnification, its cellular structure eventually becomes visible.

Right at the upper edge of a petal, an unusual histogram-like pattern can be observed.

When a flower opens sufficiently, its reproductive structures become visible.

To get a clearer view, I have removed all but two of the petals.  Protruding from the top of the stalk is the white pistil, topped by the stigma.  Surrounding the pistil is a ring of six stamens.

Two closer views reveal more details.  The stigma is tri-lobed, and is connected without a stalk to the light greenish-white ovary.  A stigma without a stalk (or style) is referred to as sessile.  The six pollen covered anthers are supported by rod-like filaments.

Notice in the more highly magnified view of an anther shown below, that it is composed of four parallel segments.  Tulip pollen is dark in colour and can be seen clearly if it gets on hands or light-coloured clothing.  (The dark out-of-focus spots that can be seen on the yellow base of the petal at left are actually clumps of this dark pollen.)

When examined under the microscope, the cellular structure of one of the supporting filaments is colourful!

Several clumps of irregularly shaped pollen grains can be seen clinging to a filament in the two images that follow. 

Several anthers in the flower appeared to have this strange folded shape at their bases.  At this magnification it is almost possible to see individual pollen grains on the anther’s surface.

By sliding the dark-ground condenser slightly out of the optical path, it is possible to show the pollen grains adhering to the edge of an anther.  In this light, they appear to have a purple colour.

This same purple colouration also appears in a higher magnification phase-contrast view of a single pollen grain.

The three images below show the top of the tri-lobed stigma.  Each lobe appears to have a deep groove in its upper surface, no doubt to increase its surface area (and therefore its pollen collecting capability).  Dark pollen grains can be seen clinging to the stigma’s surface in all three images.

Photomicrographs showing the surface of the stigma can be seen below.  Note the hair-like protuberances that cover the surface.  Pollen grains, carried to the stigma by visiting insects, are caught by these hairs.

Botanical tulips” like the parrot tulips studied in this article, are marvels of what modern biological science can produce.  How strange it is to consider that a louse carried virus produced such stunningly colourful blooms.  How wonderful that science could retain the striking characteristics, while removing the disease!

In part two of this article (below), a different parrot tulip, with even stranger sculptural qualities, is examined macro-photographically.

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 dark ground and phase-contrast condensers), and the Coolpix 4500.

Further Information

Tulips         http://bell.lib.umn.edu/Products/tulips.html

The history of the Tulip     http://www.geocities.com/Salhanie/contents.html

Tulips     http://www.holland.nl/uk/holland/sights/tulips-history.html

Tulip (Tulipa)     http://encyclopedia.jrank.org/TOO_TUM/TULIP_Tulipa_.html

How did a flower cause an economic disaster?


 All comments to the author Brian Johnston are welcomed.

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