"When you are sitting around and admiring your Christmas tree, consider that it owes its existence in part to this clever microscopic valve," says John Sperry, a University of Utah biology professor who led the research team. "Without these valves, conifers could be much less common than they are, and conceivably their survival might be marginal."
The journal Science is publishing the study Dec. 23, two days before Christmas.
Sperry says that if conifers had not evolved easy-flow valves to make up for the short length of their water pipes or conduits, "it is doubtful they could hold their own with angiosperms [flowering trees] in today's forests. It's doubtful they would dominate whole regions of North America."
While scientists cannot really know if conifers might have gone extinct without their efficient type of water valve, "what this study shows is that without this valve, it would be 38 times harder for conifers to take up water, which would put them at a serious disadvantage in competition with flowering trees in temperate forests," says Sperry.
The study was part of a University of Utah doctoral thesis by Jarmila Pitterman, now a postdoctoral fellow at the University of California, Berkeley. She and Sperry conducted the study with other University of Utah biologists: Uwe Hacke, a research assistant professor; lab technician James Wheeler, who has since left for graduate school at Harvard University; and Elzard Sikkema, an undergraduate.
The Plumbing System of Trees
The numerous parallel "pipes" that carry water