Untersuchungen über Stickstoffverhindungen und Chlorophyll während des Vergilhens der Laubblätter von Ginkgo biloba

Abstract

Summary Ginkgo leaves of different age were isolated and cultivateted in the light and in the dark. 1. Isolated leaves yellowing in the light. Leaves cultivated in the light (except young leaves) died at about the same times as did leaves under natural conditions. Their metabolism was influenced by the time of isolation. The spectrum of amino acids was comparable to that of leaves yellowing on the tree. Prolin was the main amino acid. 2. Isolated leaves yellowing in the dark. All leaves died after maximal 40 days of cultivation in the dark and showed a catabolic metabolism of protein and chlorophyll. In the yellow leaves the main soluble nitrogen compounds were the amides (especially glutamin), ammonia and valin. The typical catabolic impulse in protein metabolism of autumn leaves seems to be partly controlled by other parts of the plant. Another process of aging causes the yellowing of young isolated leaves in the light.