Ultrastrutture plastidiali in foglioline di gemme di « Picea excelsa » e di « Larix decidua » nel corso della germogliazione

Abstract

Ultrastructural modifications of plastids in leaflets of Larix decidua and Picea excelsa during sprouting of buds.—Ultrastructural modifications of plastids in leaflets of Larix decidua and Picea excelsa during sprouting of buds kept in different light conditions were observed.

While in quiescent buds of both species typical plastids with magnograna are present, fully expanded leaflets kept in the light have plastids with an organized lamellar apparatus.

When the buds are kept in darkness the cells of the fully expanded, etiolated leaflets have hardly differentiated plastids with prolamellar bodies partially modified into short tubules and vesicles.

Plastids of Picea and Larix buds, in their development, behave almost identically both in darkness and in the light.

The differences previously observed in dark grown seedlings of the two species are not to be found in buds.