Variation in Salt Secretory Activity of Microhairs in Grasses

Abstract

Salt secretory activity of leaf microhairs in 18 grass species was examined by quantitative ion chromatography of washings, and directly by scanning electron microscopy and qualitative energy dispersive X-ray microanalysis of microhair secretions. The sample represented the subfamilies Chloridoideae, Arundinoideae, Panicoideae and Bambusoideae, including microhairs of the 'chloridoid', 'panicoid' and 'Enneapogon' morphological types, and exemplified forms with and without 'partitioning membranes'. Salt secretion by microhairs was detected only in certain Chloridoideae, all having 'chloridoid type' microhairs with basal cell partitioning membranes. Salt secretion was not detected with any of the microhairs lacking basal cell partitioning membranes; and 'chloridoid type' microhairs of Sporobolus elongatus and Eleusine indica were not seen to secrete salt, despite their possession of partitioning membranes.