Rumen Microbial Degradation of Potassium Hydroxide-treated Coastal Bermudagrass Leaf Blades Examined by Electron Microscopy

Abstract

Potassium hydroxide-treated and untreated Coastal bermudagrass leaf blades were compared for variations in cell wall digestion by rumen microorganisms. Scanning electron microscopy was used to study the relative rate and extent of cell wall digestion. Transmission electron microscopy was used to compare the manner of rumen bacterial degradation of treated and untreated tissues and cell walls. Potassium hydroxide treatment disrupted tissues, separating parenchyma bundle sheaths, inner bundle sheaths and sclerenchyma tissues into individual cells. Rumen microorganisms degraded the more easily digested tissues (mesophyll) and the more slowly degraded tissues (parenchyma bundle sheath and epidermis) faster in treated blades than in untreated blades. Alkali treatment of the slowly degradable cell walls resulted in decreased electro i density (shown by transmission electron microscopy) and increased availability of cell walls to nearby and attached bacteria. Treated lignified cell walls were attacked by rumen bacteria and the intercellular layers were easily degraded, whereas similar untreated tissues were resistant to microbial attack. Potassium hydroxide treatment resulted in a substantial increase in protozoal association with leaf blades. Copyright © 1980. American Society of Animal Science . Copyright 1980 by American Society of Animal Science