Inactivity of the carotene‐oxidising system in iris leaf

When green leaves were severely damaged by grinding to pulp, a quarter of the carotene was lost by enzymic activity in about 13 min. at room temperature. The enzyme was found in 20 species of leaves; also in pods, green fruits, stems and other chlorophyll‐containing parts of plants. (Some of the species treated have nutritional value.) The enzyme was not found in most of the chlorophyll‐free materials that were tested. Carotene was stable in macerated leaf of iris. The iris was the only exception found to the rule that chlorophyll in higher plants is accompanied by the carotene‐destroying enzymic system. Other respects in which iris differed from other species are discussed.