Agriculture Reference
In-Depth Information
1
HOW P L A N T S G ROW
Cambium-theunitingforce
Scratch a woody twig and you will find a
bright green layer called the cambium. The
two plant parts, roots and shoots, growing in
different directions, are united by a complex
'plumbing' network. This is known as the
cambium layer. This layer links the
microscopic root hairs gathering soil
nutrients and water, with the shoots and
leaves manufacturing food (see Figure 1.1).
These two elements combine and are spread
through the plant from the veins in every leaf
to the tip of every root.
The cambium layer consists of vascular
bundles made up of two distinct types of
'plumbing' or vessels (see Figure 1.2).
The xylem and phloem form the core of the
root. The xylem takes up the water and the
phloem takes up minerals from the soil via
Figure 1.1
The xylem carries water and moves in one direction - straight up from the roots - and exits as water vapour
through the leaves. The contents of the phloem move osmotically in both directions, carrying nutrients from the roots
combined with simple sugars manufactured in the leaves. Together they penetrate and sustain all living parts of the
plant.
