The photos of this beautiful botanical preparation - a cross section of a rhododendron's flower bud - show many parts of this special organ of the plant. The names of many parts are indicated in the illustration shown below. It is going too far here to go into depth about all details.
Rhododendron flower bud cross section.
The picture on the left shows the inflorescence of this plant. There is a main axis with flower stems at different heights. The flower stems shorten from bottom to top but are almost flat. At the bottom of the flower stems are two bracts, the bracteoli.
In the main axis of the flower bud, we distinguish the bark cylinder with the epidermis and the bark parenchyma. Furthermore, we see the central cylinder with vascular bundles and marrow parenchyma. On the epidermis of the main axis and also in other places in the preparation we see a lot of trichomes and glandular hairs (protective function)
In the pollen sacs there are pollen tetrads. These are four daughter cells, the spores, which were created after meiosis of a mother cell. These daughter cells are still connected to each other before they come apart later and develop into pollen that then will have a specific double cell wall.
In the photos we also see that the pollen sacs are still connected to each other. Gradually, the parenchyma that still separates two pollen sacs will be "digested", leaving one pollen sac, on the left and right of the intermediate vascular bundle. Finally, the epidermis layer of the pollen sack will burst open with age and by drying out and the ripe pollen grains will be released.
In the multi-local ovaries, we can recognize the zone in which two ovules will develop in each compartment.
© www.willemsmicroscope.com
With thanks to Dora De Cremer PhD Biologist
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