Peripheral structures of plastids and ultrastructural localization of acid phosphatase and succinic dehydrogenase in a variegated Betula pubescens mutant

Abstract

In white leaf tissue from a variegated Betula pubescens mutant, acid-phosphatase activity is seen only in the vacuoles and the cell wall and no precipitation is evident inside the mutant plastids. The electron-microscopic localization of succinic dehydrogenase reveals activity in the intracristal spaces of mitochondria and the envelopes of both mitochondria and plastids. Since precipitation is not apparent inside the protrusions of the plastids and only the membrane occasionally shows a typical mitochondrial reaction, evidence seems to be lacking which indicates that mitochondria originate from plastids. The mitochondrion-like particles budding from the mutant plastids are considered to be proplastids. Peripheral vesicular structures are also seen in the chloroplasts of green leaf tissue from plants growing at high light intensities.