Abstract: A cytochemical technique was used to determine whether gemerative cell and yegetative nucleus at various stages of the developing male gametophyte of Clivia nobilis and Amaryllis vittata have ATPase activity. All the studies were carried out in Wachstein-Meisel's medium (1957). The pH optimum for this reaction was pH 7.2. Comparing with the results obtained from the normal development %f male gametophytes, under the same measured conditions, the abortive pollen, the boiled and dried male gametophytes, in which protoplasmic streaming had stopped for more than 24 hours, showed negative reaction. The results obtained from the male gametophyies with normal development are briefly summarized as follows: 1. The presence of ATPase in the cultured male gametophyte: By cytochemical procedures for localizing ATPase activity: ATP-dependent reaction product in living samples or in the samples dehydrated by 80% aleohol in a short time as the pretreatment, is found to be confined to: (a) the growth region at the tip of the pollen tube and the dense region of protoplasmic stream, (b) generative cell (sperms) and (c) vegetative nucleus. Therefore, the Mg2+ and ATPase-dependent cytochemical reaction, and the specific localization of reaction product, have strongly suggested that the appearance of lead phosphate precipitate was due to the ATPase activity in the male gametophyte. 2. The range of ATPase relative activity at various stages of development of male gametophyte: the ATPase activity in generative cell at various stages of its development changes in the range from the 1st degree (light-brown) to the 5th degree (black), but in vegetative nucleus it changes only from the 2nd degree (brown) to the 3rd (dark-brown). 3. The relation between ATPase activity and cell action: from the results, it can be seen that the higher the ability of cell movement and cell activation is, the greater is its ATPase activity. So the relative ATPase activity is in close relation to the mechanical movement of generative cell and vegetative nucleus and their physiological state. 4. The vegetative nucleus is a physiologically active organelle, due to its own ATPase system. Many experimental facts revealed that the. vegetative nucleus might play an important role in mitosis of the generative cell and in formation of sperms.