Abstract
5-Hydroxytryptamine (5-HT, serotonin) is widely distributed in both the vegetal and animal kingdoms. The biological importance in plants of an analogue of serotonin, the auxin, 3-indolylacetic acid, has been well known. Recently, it has also been reported that serotonin is present in several vegatebles. The fluorescence histochemical demonstration of monoamines has been developed by Scandinavian investigators (1). This technique, now widely available, has made a great contribution to the study of neuron activity in animals. Udenfriend et al. (2) were the first to demonstrate the physiologically abundant presence of monoamines in plants such as; Musa paraddiaca L. (banana), Lycopersium esculentam Mill. (tomato) and Persea Americana Mill. (avocado). Monoamines have been found in the fruits and leaves of these plants and the contents have been reported shortly. However, no histochemical study on the distribution of the amines have been done. In the present experiments, the author attempted to demonstrate histochemically the presence of monoamines, especially serotonin, in the various organs and tissues of Musa Basjoo SIEB. (plantain), Musa paradisiaca L. (banana), Allium Cepa L. (onion) and other plants.
