Abstract Detail

Physiological Section

McCulloh, Katherine [1], Sperry, John S. [1].

Do plants comply with Murray’s law?.

Murray’s law describes the optimal design of a vascular system that maximizes hydraulic conductivity per investment in vascular tissue. The law states that the optimal structure will conserve the sum of the conduit radii cubed at every level of the vascular system. Although the law was derived for the cardiovascular systems of animals, it should apply to plants and surprisingly has not been examined extensively. We hypothesized that the xylem conduits of plants would obey Murray’s law when they are not providing the plant with structural support in addition to transporting water. Compliance with Murray’s law was assessed by direct measurements of conduit radii at various levels within plants. We tested compound leaves, vines, and freestanding trees with ring-porous, diffuse-porous and coniferous wood anatomy. We found compliance with Murray’s law in the leaves, vines and ring-porous wood, where xylem conduits were predicted to not contribute to the structural support of the plant. In contrast, the diffuse-porous and coniferous species deviated from Murray’s law, which is consistent with our prediction that the xylem conduits in those wood types provide structural support.

1 - University of Utah, Department of Biology, 257 S. 1400 E., Salt Lake City, Utah, 84112, USA

Keywords:
xylem transport
wood anatomy
Murray's law.

Presentation Type: Paper
Session: 11-4
Location: White Pine (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 10:45 AM
Abstract ID:223