Stomatal Guard Cell Integrity and Resistance to Rumen Fluid Digestion
1974
Chatterton, N. J. | Powell, Jerrel B.
Scanning-electron micrographs were made of Dactylis glomerata L. leaf tissue following digestion in rumen fluid to observe differential digestion of various cell types. Fresh leaf blade sections were subjected to the activity of rumen fluid at 39C obtained from a rumen-fistulated Black Angus steer. Digestion by rumen microorganisms allowed the cuticle to float free as the mesophyll was digested. Close examination revealed that the stomatal guard cells were slow to digest and that they remained attached to the interior surface of the cuticle. The lack of significant microorganismal entrance into fresh leaf tissue, except through cut edges, may be explained by the combined resistance of the cuticle and stomatal guard cells to digestion. We propose that the cellulose of guard cell walls of Dactylis glomerata L. is infused with either a cutin-like compound or with silica. Possibly a combination of cutin and silica provides guard cells with resistance to digestion by rumen fluid organisms. Additionally, electron micrographs are presented that vividly display the shape and orientation of the guard cells from a new perspective.
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