Article - Fall Leaf Color Change Process

Short article from Harvard's Harvard Forest site that explains the process of Fall leaf color change.
Link: http://harvardforest.fas.harvard.edu/research/leaves/process.html

Dramatic diversity of columbine flowers explained by a simple change in cell shape

Cambridge, Mass. - November 15, 2011 - Columbine flowers are recognizable by the long, trailing nectar spurs that extend from the bases of their petals, tempting the taste buds of their insect pollinators.

New research at Harvard and the University of California, Santa Barbara (UCSB) helps to explain how columbines have achieved a rapid radiation of approximately 70 species, with flowers apparently tailored to the length of their pollinators' tongues.

Bees, for example, enjoy the short spurs of Aquilegia vulgaris, whereas hawkmoths favor A. longissima, whose spurs can grow to up to 16 centimeters.

According to results published today in the Proceedings of the Royal Society B, the dramatic diversity in the length of the columbines' spurs is the result of one simple change during development: the extent of cell elongation.

"The evolutionary importance of interactions between flowers and pollinators has been recognized for centuries," says co-lead author Sharon Gerbode, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS).