Cytological and anatomical changes in pine tree xylem caused by sulphur compounds

In areas intensely contaminated with sulphur compounds some pine trees (Pinus sylvestris L.) have deformed branches with numerous short sprouts. In the branches lenticular areas with considerably changed xylem elements are found. In these greatly changed xylem areas (GCXAs) deformed tracheids are almost isodiametric, some form hooks and loops. The tracheids and ray parenchyma cells show a differentiated level of cell walls lignification. A significantly larger number of rays and the so-called pseudorings are observed.