CBSE Class 10 Answered

Plant cutting, also known as striking/cloning, is a technique for vegetatively (asexually) propagating plants in which a piece of the source plant containing at least one stem cell is placed in a suitable medium such as moist soil, potting mix, coir or rock wool. The cutting produces new roots, stems, or both, and thus becomes a new plant independent of the parent.

To have a fair amount of cuttings catching on, the cutting should have good, moist soil with sufficient nutrients, a humid environment and partial shade (to prevent the cutting from drying out). After cuttings are placed in soil, they are watered thoroughly with a fine mist. After the initial watering, soil is allowed to almost dry out before misting again, with the aim to keep the soil moist but not wet and waterlogged. In addition, the cutting needs to be taken correctly at the right time; with the right size and amount of foliage.

Many vegetative parts of a plant can be used. The most common methods are

• Stem cuttings
• Root cuttings
• Scion cuttings
• Leaf cuttings.

Layering:

Layering is a means of reproducing plants by placing an intact branch or stem in contact with soil, encouraging it to send out roots. Once rooted, the branch can be severed from the mother plant, roots and all, and planted elsewhere. Layering has evolved as a common means of vegetative propagation of numerous species in natural environments. Layering is also utilised by horticulturists to propagate desirable plants.

The horticultural layering process typically involves wounding the target region to expose the inner stem and optionally applying rooting compounds. In ground layering, the stem is bent down and the target region buried in the soil. Layering is more complicated than taking cuttings, but has the advantage that the propagated portion can continue to receive water and nutrients from the parent plant while it is forming roots. This is important for plants that form roots slowly, or for propagating large pieces .

Grafting:

Grafting is a horticultural technique used to join parts from two or more plants so that they appear to grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (rootstock) of another plant.

In grafting, one plant is selected for its roots, and this is called the stock or rootstock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion. The scion contains the desired genes to be duplicated in future production by the stock/scion plant. For successful grafting to take place, the vascular cambium tissues of the stock and scion plants must be placed in contact with each other. Both tissues must be kept alive until the graft has taken, usually a period of a few weeks. Successful grafting requires that a vascular connection takes place between the two tissues.  

Grafting is most commonly used for the propagation of trees and shrubs grown commercially. Grafting is limited to dicots and gymnosperms.