Isolation and Separation of Epidermal and Mesophyll Protoplasts from Rye Primary Leaves — Tissue-Specific Characteristics of Secondary Phenolic Product Accumulation

We have developed a technique for the large-scale isolation of epidermal and m esophyll proto­ plasts, as well as the vascular strands, o f rye primary leaf blades. Separation o f the two types of protoplasts has been successful only from leaves harvested at the end of a 13-h light period, when chloroplasts were enriched in starch. The occurrence o f different flavonoid compounds, and amounts, in epidermal and m esophyll protoplasts can be used as criteria for protoplast purity and viability since C-glucosylflavone Oglycosides are characteristic of epidermal protoplasts whereas flavone O-glucuronides and anthocyanins are typical o f mesophyll protoplasts. Several non-flavonoid phenolic com pounds are found only in the epidermal protoplast. These patterns of secondary product accumulation reflect the high tissue specificity of the rye leaf.