Natural vegetative reproduction is a form of asexual reproduction in which a bud grows and develops into a new plant. The buds may be formed in organs such as root, stem and leaf. At some stage, the new plant gets detached from the parent plant and starts to develop into a new plant. Some of the organs involved in the vegetative reproduction also serve as the organs of storage and perennation. The unit of reproductive structure used in propagation is called reproductive propagules or diaspores. Some of the organs that help in vegetative reproduction are given in Figure 1.1.
The roots of some plants develop vegetative or adventitious buds on them. Example Murraya, Dalbergia and Millingtonia. Some tuberous adventitious roots apart from developing buds also store food. Example Ipomoea batatus and Dahlia. Roots possessing buds become detached from the parent plant and grow into independent plant under suitable condition.
From the Unit 3 of class XI (Vegetative morphology) you are familiar with the structure of various underground stem and sub aerial stem modifications. These include rhizome (Musa paradisiaca, Zingiber officinale and Curcuma longa); corm (Amorphophallus and Colocasia); tuber (Solanum tuberosum); bulb(Allium cepa and Lillium) runner (Centella asiatica); stolon (Mentha, and Fragaria); offset (Pistia, and Eichhornia); sucker (Chrysanthemum) and bulbils (Dioscorea and Agave). The axillary buds from the nodes of rhizome and eyes of tuber give rise to new plants.
In some plants adventitious buds are developed on their leaves. When they are detached from the parent plant they grow into new individual plants. Examples: Bryophyllum, Scilla, and Begonia. In Bryophyllum, the leaf is succulent and notched on its margin. Adventious buds develop at these notches and are called epiphyllous buds. They develop into new plants forming a root system and become independent plants when the leaf gets decayed. Scilla is a bulbous plant and grows in sandy soils. The foliage leaves are long and narrow and epiphyllous buds develop at their tips. These buds develop into new plants when they touch the soil.
· Only one parent is required for propagation.
· The new individual plants produced are genetically identical.
· In some plants, this enables to spread rapidly. Example: Spinifex
· Horticulturists and farmers utilize these organs of natural vegetative reproduction for cultivation and to harvest plants in large scale.
New plants produced have no genetic variation.