Small Grain Crop Forage Potential: II. Interrelationships Among Biological, Chemical, Morphological, and Anatomical Determinants of Quality1
- J.H. Cherney and
- G.C. Marten2
Morphological and anatomical studies are needed to help explain forage quality variation in spring-sown small grain crops. Our objectives were to determine whether morphological features can explain changes in forage quality of small grain crop forages as they mature, and whether barley (Hordeum vulgare L.) and oats (Avena sativa L.) differ in the way their anatomy changes as they mature.
Two cultivars each of spring wheat (Triticum aestivum L.), oats, triticale (Triticum durum Desf. × Secale cereale L.), and barley were harvested at a wide range of maturity stages. Stem, leaf sheath, leaf blade, and inflorescence components of forage samples were analyzed for quality constituents. Cross-sectional areas of leaf blade, leaf sheath, and stem were measured in barley and oats.
Barley forage was more digestible than that of oats largely due to a greater proportion of highly digestible inflorescence in the total dry matter of barley at all stages. A progressive increase in inflorescence digestibility, along with a progressive increase in proportion of inflorescence during grain filling, partly offset the declining digestibility of the stem, leaf blade, and leaf sheath in all crops as they matured. Lignin concentration increase in the stem was the major factor that accounted for reduced digestibility with increased maturity.
Percentages of total area in cross sections occupied by lignified cells were not well associated with lignin concentration of the morphological components of barley and oats. Areas containing lignified cells in the vascular bundles, bundle sheaths, and bundle sheath extensions of leaf blade and sheath appeared to be fixed by the time of the flag leaf stage in barley and oats. Barley had less percentage lignified area in the leaf blade and sheath than did oats, which may help explain the higher digestibility of barley leaf blade and sheath.
Anatomical anomalies were found in the vascular bundles of stems of both triticale cultivars.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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