Horticulture 202H Lab 9
Plant Propagation by Cuttings
When plants are propagated by taking a cutting from an existing plant, the resulting progeny are genetically identical to the parent plant, ie, they are clones of the original plant. The ability to clone plants has been important to horticulturists for many centuries, allowing the multiplication of plants with superior fruit production, growth or ornamental attributes.
Cuttings may be a whole stem, a piece of stem, or a piece of leaf or root. Cuttings taken from a stem or piece of stem form roots and the resulting shoot generally grows from a preexisting meristem (usually the terminal or lateral bud). Cuttings taken from leaf or root tissue require the development of new vegetative shoot meristems. These meristems are adventitious. In some cases the adventitious meristems do not faithfully reproduce the clone (as is the case for chimeras); such plants must be rooted from tissue containing a preexisting meristem.
Propagation by rooting requires control of several variables.
- Excessive desiccation of cuttings during rooting must be prevented by placing cuttings in a moist medium, in a poly tent, and/or in a mist bed.
- Cuttings are generally shaded to prevent excessive water loss and leaf scorching.
- The rooting medium must allow excellent aeration around the rooting zone.
- Supplemental heat to overcome the cooling effect of mist may be necessary.
- Some difficult to root cuttings may benefit from topical auxin applications to stimulate rooting.
This exercise will illustrate cutting propagation of plants using several different cutting types.
- Select 30 tip cuttings from the plants provided (Rose, coleus and/or bush morning glory (Ipomea fistulosa). Choose healthy cuttings that appear "normal" for the plant being propagated ("normal" in this context means neither stunted nor excessively elongated).
- On 10 cuttings, remove one-half the leaves. On 10 cuttings, remove all leaves. Leave the remaining 10 cuttings largely intact, removing only the leaves on the part of the stem that will be stuck below the rooting medium.
- Trim the cuttings with a sharp knife and place them into the rooting medium as quickly as possible.
- After all cuttings have been placed in the rooting flat, place the flat in the mist bed.
- Observe the cuttings weekly and record the date of first root emergence.
Plant Name Cutting Type Date of First Root Development
1. What are the benefits of propagating plants by cuttings?
2. What effect did removing the leaves have in your experiment?
3. Would your plants have rooted better if an auxin was applied?