부산대학교 도서관

Several microscopic techniques have been used to measure plant tissue degradation by rumen microorganisms. Our objective was to develop a less subjective method for measuring plant tissue degradation using computer‐based image analysis rather than visual appraisal. Three millimeter segments of leaf blades from ‘Cave‐In‐Rock’ switchgrass (Panicum virgatumL.) were placed either directly into a fixative or into buffered rumen fluid for 48 h. Segments were retrieved and prepared for light microscopy by fixation, dehydration, embedding, trimming, and sectioning at a thickness of 2 μ. Tissues in cross section were measured with an optical image analysis system and each tissue type was classified as undigested, partially digested, or completely digested. The relative proportion of tissue types in undigested samples ranged from 1.9 ± 0.20% for phloem tissue to 35.9 ± 1.26% for mesophyll tissue. Standard deviations of measurements from digested samples ranged from 1.1 to 12.2%. Degradation of xylem and phloem was difficult to measure and had the highest standard deviations of 9.8 and 12.2%, respectively. This method requires approximately 15 min per sample, and although it is more time consuming than visual estimation methods, it has the advantage of measuring extent of digestion on an area basis more objectively than other methods currently used.