Abstract
Several changes have been observed in the ultrastructure of the mesophyll of larch needles under the effect of SO2 swelling and degradation of the thylakoids, granulation of the cytoplasm and plastid matrix, degradation of the ribosomes and of endoplasmic reticulum, agglutination of the chromatin, and cell plasmolysis. Comparison of the ultrastructure in two larch-trees characterized by different susceptibility to SO2 appeared to be difficult due to the lack of synchronousness in the reaction of particular cells to this gas.