1) Flower
The flower contains the organs of plant sexual reproduction
It attracts insects needed to carry the pollen between plants to allow pollination
It's really important for reproduction

2) Stem
The stem is the organ which holds the leaves upright in the air and facing the light
It carries water and minerals to the leaves, and food around the plant
The stem is important for nutrition, excretion and growth

3) Leaves
The leaves are the organs of photosynthesis
They make all the food that the plant needs
Leaves contain chlorophyll, which uses light energy to change carbon dioxide and water into glucose
They have tiny little pores, which allow essential carbon dioxide in and waste gases out
Leaves are important for nutrition and excretion

4) Roots
The root is the organ which provides anchorage for the plant so that it does not blow away or fall over
With its root hairs it provides a big surface area to help take in water and minerals from the soil - these are both essential for photosynthesis
The root is therefore important for nutrition