Fig. 7.5-4b. Transverse section of a V-shaped vascular bundle in a stem of asparagus (Asparagus). As in Fig. 7.5-4a, there are two large cells here that are differentiating into vessel elements, but which have not yet begun to deposit secondary wall. These too have been plasmolyzed by the processes of fixation and dehydration. These cells are very large, but are filled mostly with a large central vacuole rather than a large amount of cytoplasm. Such large central vacuoles are very difficult to preserve well, and they almost always collapse, as they did here.