Chapter 10

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. Note that you will lose points if you ask for hints or clues!



1. The process by which growers increase their supply of a type of plant is called .

2. Propagation which does not involve flowers, seeds or sexual reproduction is called propagation.
3. Some methods of vegetative propagation make use of propagation structures formed by the plant.
4. Natural methods include using food storage organs such as and and making use of plantlets. A is a miniature plant attached to a plant. Plantlets are found at the ends of (horizontal stems) and at the edges of some plants’ leaves. Others take the form of side shoots called formed at the base of the parent plant.
5. Some methods of vegetative propagation can be used to increase the supply of the plant by means. Plants are often propagated by taking . When a cutting is taken, the stem is normally cut just below the because the node is a point of growth. It will respond to the cut (wound) by developing . Some plants can be propagated using cuttings.
6. The development of roots by a cutting is often promoted by applying a chemical called powder to the cut surface.
7. A stem cutting with many leaves may lose too much water and die before its roots develop. To prevent this happening, most of its are removed or it is given conditions with an increased level of . This can be done by enclosing it in a bag or by putting it in a propagator.
8. Plants can also be propagated artificially by . This means pegging the stem down in the soil until roots form at the nodes. Sometimes the stem is , part the way through, below a node before being down.
9. An advantage of layering is that it can be used with plants that are or impossible to propagate from cuttings.
10. Supplying the plants being propagated with may be of advantage if it leads to growth and/or prevents damage. However these benfits have to be balanced against the possible disadvantages. These include wilting of plants (caused by high loss in warm conditions), rapid spread of and high costs.