Cloning Plants

There are two ways that plants can reproduce:

  • Asexually – Produces offspring that are genetically identical to the parent
  • Sexually – Produces offspring that are genetically different from the parents

Sexual reproduction can lead to offspring with genetic variation, which might make them better adapted to changing environments. However, when the goal is to produce plants with specific, identical characteristics, asexual reproduction is generally preferred.

For example, if we want a specific shade of pink flowers, asexual reproduction can give us our desired characteristic. This process is also called cloning and the genetically identical offspring are called clones.

Although genetic engineering has given us a variety of ways to clone plants, we will discuss two simple methods for cloning:

  • Cuttings
  • Tissue Culture

Cuttings

Taking cuttings is one of the simplest methods to produce identical plants quickly and cheaply. Gardeners have been using this method for a long time to grow plants with desirable characteristics.

It involves cutting a part of the plant (preferably a growing shoot, or branch) and planting the cutting in fertile compost. Basic environmental needs such as adequate sunlight and water also need to be met. Soon, the cutting grows into a new plant that is genetically identical to the parent plant (the original plant which the cutting was taken from). In other words, it is a clone of the parent plant.

  • Hormones are often used to encourage the growth of new roots.

Tissue Culture

Taking cuttings is a reliable method to clone plants, but what happens when you need to clone a larger number, for example, one hundred plants? Cuttings wouldn’t be the best way to clone that many plants.

Tissue culture (otherwise known as micropropagation) allows you to clone many plants at the same time. This process involves:

1. Obtaining very small pieces of plants called explants.

2. Growing the explants in vitro (outside a living organism) using sterile agar jelly.

  • This jelly contains nutrients and plant hormones.

3. The cells grow into small masses of plant tissue (callus tissue).

4. This tissue grows and forms plantlets. These plantlets can then be transferred to potting trays, where they develop into full plants.

Tissue culture is a method that allows you to clone a large number of plants simultaneously. However, it tends to be more costly than using cuttings. Also, it’s essential for the agar jelly to be sterile; if not, microorganisms might interfere with plant growth.

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