Concept preview

What you will be able to do

1. 01Describe the functions of roots, stems and leaves and how each is adapted to its job.
2. 02Explain the three tissue systems (dermal, ground, vascular) and where each is found.
3. 03Compare xylem and phloem in structure and function.
4. 04Use features such as veins, bundles and cotyledons to tell monocots from dicots.

A flowering plant may look far simpler than an animal, but it is a superbly organised body, and almost every part of it belongs to one of just three organs: the root, the stem and the leaf. Each organ is shaped for a particular job, and together they solve the central problem of a plant's life, which is that its two vital resources lie at opposite ends of its body. Water and minerals are in the soil below, while light and carbon dioxide are in the air above, so a plant cannot gather everything it needs in one place the way a mobile animal can. The root reaches down for water and anchorage, the leaf spreads out in the light to photosynthesise, and the stem connects the two, holding the leaves up and carrying materials between root and leaf. Understanding a plant means understanding how these three organs are built and how their internal tissues let each do its work.