Hydraulic conductance and tracheid anatomy in six species of extant seed plants

摘要: Hydraulic conductance of tracheids was studied in either petioles or young stems six species seed plants having various types intertracheid pitting. Measured conductances were compared with estimates based on Hagen–Poiseuille flow through ideal capillaries and predictions from a biophysical model incorporating observed anatomical characteristics pits. Conductance the xylem, expressed as percentage capillary prediction, varied an average 88% for containing only very narrow to less than 35% large-diameter tracheids. The allowed fairly close all except one, where estimate pit membrane resistance could not be experimentally obtained. For individual tracheids, largely function lumen diameter, resistivity, exposed area membranes, determined by shape, size, frequency. ...