Parenchyma tissue stores synthesised organic food such as starch. Intercellular air spaces allow the exchange of gases . The vascular bundles are found scattered throughout the ground tissue . The vascular bundles occurring nearer the rind of the stem are smaller and are closer to one another. The vascular bundles contain no cambium and consequently secondary thickening does not occur.
Sclerenchyma sheaths protect the vascular bundles and give strength to the stem.
Xylem Large xylem vessels are found within an irregular intercellular air space called the lysigenous cavity. This space is surrounded by thin-walled parenchyma cells. Functions of the Xylem Xylem transports water and dissolved ions from the root system to the stem. The lignified thick-walled xylem cells strengthen the stem. Phloem Phloem is composed of thin-walled cells, viz.