Abstract: Mature albuminous cells which are connected with differentiated and functional sieve cells show rather high activity of acid phosphatase at pH 5.0. No increased activity could be detected in ordinary ray cells, cambium cells and young albuminous cells contiguous with developing sieve cells. Collapsed albuminous cells show little or none of the activity. With ATP as substrate, enzyme localization is the same as with β-glycerolphosphate. When adenosine triphosphatase activity is visualized at pH 7.2 with ATP as substrate, the highest activity still localized in mature albuminous cells. With the development of young albuminous cells, the enzyme activity is being gradually exhibited, but disappearing when the maturecells begin collapsing. On the other hand, in ordinary ray cells the enzyme activity is ahnost not detectable.

Key words: Pinus bungeana Zucc., Acid phosphatase, Adenosine triphosphatase, Albuminous ceils