Spring is again upon us and the first flowers are beginning to appear! Part of this suite is a mixed collection of pictures of these flowers, which can be accessed by clicking the link to Index of Flower images
Flowers are of course not just there to please us, but serve a vital role in attracting insects to aid in their propagation. The insects carry the pollen from one flower to fertilise another. However, pollen that has landed on the female stigma of a flower has to transmit its genetic information down to the ovary, often hidden away! The pollen does this by germinating a long tube which grows into the plant until it reaches the ovary. This pollen germination can be triggered to occur away from the plant for many species. I have done this by placing pollen on a strip of thin onion skin in a humid chamber for four hours. The main aim of this suite is to study this phenomenon to see how widespread it is. What germinated pollen looks like for a variety of flowers can be seen by accessing the link to the Index of pollen germination images.
Some plants are more closely related to each other in an evolutionary sense than others. I was therefore intrigued to see whether this was reflected in the ability to germinate pollen away from the plant on which it would normally land. The results are expressed in a simple branching figure called a 'Dendrogram'.
The results from the dendrogram and the graphs suggest that two thirds of the plants tested can germinate pollen away from the plant. The results are fairly consistent within a variety. Pollen germination tends to split into those that can and those that cannot with fewer in-betweenies. However, even quite closely related plant varieties can differ in their ability to germinate. The tulips and daffodils are good examples, some varieties do germinate, some do not. Why is this? Perhaps in these groups of plants ability for pollen germination away from the plant is naturally present but could be lost by breeding or mutation.
John Garrett, another Micscape contributor has previously described
his luck with the same
method of pollen germination and also contributed results to this study.
These pages are the culmination of several months work over the Winter/Spring of 1999/2000 followed by analysis. The following links take you to an extended article written more for the professional scientist with links to the original data before analysis as well as graphs interpreting the results.
Main article Raw Data Graphs
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