How do Plants Control Their Shapes?

Tammy Kang, a student in the BCIT/UBC Biotechnology program, did experiments on how conifers such as spruce, douglas fir, and larch control how many needles they first form. She measured the size of conifer embryos, and how many cotyledons ("seed leaves") were formed.
 
This work involved sterile tissue culturing to maintain cell lines and to induce embryo formation in three different coniferous plant genera (sitka and interior spruce, douglas fir, and larch).  Embryos are small and cotyledons are even more diminutive! Many hours at the microscope were spent in order to measure the distance across an embryo's surface and count the cotyledons.

Tammy's work added to preliminary data from earlier researchers indicating that douglas fir cotyledons are regularly spaced, similar to earlier published work on larch. This suggests that chemical or mechanical signals define spatial patterns that shape the early embryos of conifers.

Tammy also saw notable differences between the shapes douglas fir and spruce embryos produce. This points to genetic differences in the way the embryos are formed, and different ways the species might respond to or process signalling molecules such as hormones.

Tammy was supported by the Undergraduate Student Research Assistant program of the Natural Sciences and Engineering Research Council of Canada, and supervised by Dr. David Holloway of the BCIT Mathematics Department, with many thanks to the continuing support and expertise of Keith Turner and all the faculty in the Biotechnology program, and for the use of the Biotechnology laboratory facilities.