Diaphragmatic nets prevent water invasion of gas canals in Nelumbo nucifera

This study measured pore size in the net-like diaphragms of the lotus (Nelu mbo nucifera Gaertn.) and the water pressures necessary to break their meni sci. Mean pore radii were 7.0 +/- 0.3 mu m (95% confidence interval) in the rhizome and 19.0 +/- 0.5 mu m in the petiole. Nets in the rhizomes could p revent internal flooding in water depths up to 2 m, which corresponds appro ximately to the depths at which natural stands of the lotus grow. Nets in t he emergent petioles could withstand only 0.5 m of water pressure, but ther e was no relationship between pore radius and the proximity of a net to the rhizome. Their role may be to reduce the kinetic energy of incoming water. (C) 2000 Elsevier Science B.V. All rights reserved.