Abstract
In order to evaluate the digestion. in the rumen of herbage. tissues with special reference to the ceil wall, orchardgrass leaf blades were treated with pectinase and divided into three tissue fractions ; the parenchyma fraction consisting of photosynthetic parenchyma cells, the mechanical tissue fraction consisting of sclerenchyma, vascular bundle and epidermis, and the mixed tissue fraction. Recovery percentages of neutral detergent fiber (NDF) of the leaf blades in the parenchyma, mixed tissue and mechanical tissue fraction were 19, 11 and 59, respectively. The lignin content was higher in the mechanical tissue fraction than the parenchyma fraction. NDF digestibility in vitro was 96% for the parenchyma fraction and 69% for the mechanical tissue fraction, and that of the original leaf blades was an intermediate (84%) of the two fractions. These results suggest that the extent of digestion of herbages is dependent on the quantity and the digestibility of NDF in the mechanical tissue fraction, and is independent of the quanitity of the parenchyma fraction.
