Secondary Xylem

The image at left depicts two secondary xylem vessel members connected at their perforation plates to form a vessel. Xylem vessels transport water and nutrients from the soil to the various parts of the vine.

Xylem vessel elements are formed and then go through a process of programmed cell death called apoptosis. Once this process is completed, the vessels are devoid of their contents and are free to function as conducting tubes.

Longitudinal Section 400X

The secondary vessel elements in the image of the maceration at left have scalariform pits. The perforation plates at their ends are simple-showing no perforations.
Ray parenchyma cells, originating from the ray initials, are also present.
An interesting phenomenom noted in macerations of secondary root tissue is the large amount of raphide crystals present. These crystals are composed of calcium oxalate.
Vitis species produce a unique type of fiber known as a septate fiber. These fibers are living and function in the storage of starch.

Root Maceration