(ii) how to take plant cuttings as an example of a simple cloning technique

The idea

Taking cuttings is a simple cloning technique because the new plant is genetically identical to its parent. A shoot or stem cutting is removed from a healthy parent plant with a clean, sharp blade, cutting just below a node. Lower leaves are stripped so the stem can be inserted into a rooting medium such as compost or water. The cut end may be dipped in rooting powder containing auxin to encourage root formation. The cutting is kept warm and humid, often under a plastic bag or propagator, to reduce water loss by transpiration while roots develop. Once roots form, the cutting is potted on. Because no meiosis or fertilisation occurs, the offspring retains the parent's genotype, which is why cuttings are used to propagate desirable varieties quickly and reliably.

What earns the marks

• Cuttings are a cloning technique because the offspring is genetically identical to the parent plant, produced without meiosis or fertilisation.
• A shoot or stem cutting is taken from a healthy parent plant using a clean, sharp blade, cut just below a node.
• Lower leaves are removed and the cut end may be treated with rooting powder containing auxin to promote root growth.
• The cutting is kept warm and humid (for example under a plastic bag or in a propagator) to reduce transpiration while roots form, then potted on once rooted.

Common mistakes and how to put them right

• Thinking cuttings involve fertilisation or seeds.

  Put it right: Cuttings are vegetative, so no gamete fusion occurs and the offspring is a genetic clone.

• Believing rooting powder supplies all nutrients.

  Put it right: Rooting powder contains auxin to stimulate root formation, not a nutrient supply.

• Assuming any part of the plant can be used without care.

  Put it right: A healthy shoot cut just below a node with a clean blade gives the best chance of rooting.

Exam tips

• Link the technique explicitly to the definition of a clone: genetically identical offspring.
• Name the role of auxin in rooting powder rather than describing it vaguely as a 'growth hormone'.
• Explain why humidity is maintained — to reduce water loss by transpiration while roots are absent.