School of Biological Sciences,
Victoria University of Wellington,
Prof. Phil Garnock-Jones (VUW)
Dr. Peter Lockhart (AWCMEE)
Have you ever grown an African Violet as a houseplant? Or maybe been given one from your grandmother's windowsill? Has anyone ever mentioned that you could grow a brand new plant from one of the leaves? Where if you put a leaf into a glass of water, you'd see it develop roots and amazingly, some tiny baby plants, just a few weeks later?
That incredible ability to regenerate from a leaf, a cutting, even a flowerstalk, is what allowed the African Violet to become such a popular horticultural product. You see it everywhere. And yet, have you ever wondered where that trait comes from? That ease of propagation is just one of a number of features that characterizes the family it belongs to, Gesneriaceae. Other characteristics include a high number of epiphytic species, and a very wide range of morphological forms, from plants made up of just a single leaf (e.g. Monophyllaea) to large trees (e.g. Depanthus). Not one of these traits is unique to this family, but on the whole it is a rather unusually diverse family. Comparing the many wildly different species provides an opportunity to study the mechanisms behind evolutionary change, particularly using DNA fingerprinting techniques. New molecular techniques such as ISSR and AFLP have helped to distinguish differences between species at the level of DNA, and to
create phylogenies, or trees of relatedness. I plan on applying this technique to examine the South Pacific members of the Gesneriaceae family.
One species in particular became the focus of my MSc research - the only gesneriad native to New Zealand, Rhabdothamnus solandri. There are several features of this species which make it an interesting research subject:
a). It is one of just a few gesneriad species to be found at such an extreme of latitude, as the majority of the 3000 species are tropical.
b). It doesn't seem to have many close cousins, the geographically closest being found on the islands of New Caledonia and Lord Howe.
c). as a woody shrub, it is in the minority of species, with the rest of the family being herbaceous. In other families, the woody habit is often considered an ancestral trait.
d). it has a very high chromosome number, which may be a sign it is a species of great age.
Choosing to focus on tthe Gesneriaceae has been a fantastic experience! In order to develop a phylogeny of Rhabdothamnus and its South Pacific cousins, I need to analyze the DNA of actual plant material. As such, I have recently collected members of the family from the moist forests of New Caledonia (see photo inset). I also receive dried samples to analyze of additonal species native to Australia and Chile from herbariums in North America and Europe. Most exciting though, is going to the SYSTANZ workshop to meet other researchers who are also trying to understand similar evolutionary questions (see NEW ZEALAND WILLOWHERBS).