What are Vegetative, artificial Propagation and its type – Erakina

Vegetative propagation

• Vegetative propagation is the process of growing plants by the means of asexual reproduction and therefore is developed in controlled conditions. 

• Vegetative propagation or vegetative reproduction is a method of growing and developing plants from any vegetative parts of the plant. These vegetative parts such as stem, leaves, and roots from the original plant have regenerative abilities that can fully develop into a matured plant.
• Therefore, the plants that grow from this method are by asexual reproduction as well as they are artificially induced.
• Vegetative propagation consists of non-sexual vegetative parts of a plant that are developed into a fully grown plant. However, plants flourish from sexual propagation through the fusion of gametes (syngamy) leading to fertilisation. There are two types of vegetative propagation; natural and artificial vegetative propagation.
• The vegetative fragments from which the plant is grown are from a particular reproductive structure; such as bulb, rhizome, tuber, corms, and runners; this is known as natural vegetative propagation. Whereas, reproduction of plants via human intervention is known as artificial vegetative propagation.
• These propagative techniques include; grafting, cutting, layering, tissue culture, and suckering. 

Types of Vegetative Propagation

Natural Vegetative Propagation

• When a regenerative fragment of a plant is cultivated in the ground, the plant grows naturally and develops into a fully matured plant; by first developing roots. From the roots, as the plant absorbs nutrients, it emerges and blossoms by sprouting stems and leaves. A stem or a non-dried root of the parent plant is planted from which a new plant arises.
• Before a root is planted, this root should not be exposed to the outside temperature as it will dry out the root. If the root is dried, the plant will not grow and develop completely, as it will die out. Therefore, stems are mostly used for vegetative propagation. These stems can be modified to grow bulbs, rhizomes, tubers, corms, and runners. 

Bulbs

• Bulbs are formed underground that has a swollen-shaped stem. The central shoot of the new plant is used in vegetative propagation. Multiple small layers of leaves are developed around the bulb portion, which acts as a storage for food and other nutrients from which the plant gains. Some of the examples include onions, shallots, daffodils, etc. 

Rhizomes

• Rhizomes have root-like stems that are modified stems that grow horizontally underground, while new roots and shoots are developed from the nodes from the vegetative part. These rhizomes contain essential nutrients for growth such as proteins and starches.
• Therefore, the stem emerges vertically to form a new plant, while the buds develop into a new rhizome. Some examples include root ginger, iris, and turmeric. 

Tubers

• Tubers sprout from roots or stems. They are swollen stems that grow underground, responsible for storing nutrients when they are at a dormant stage. The outer surface of the tuber contains ‘eyes’ from which a new plant arises with shoots and leaves, while the bottom portion sprouts roots. One of the examples of stem tubers includes potatoes, while root tubers include sweet potatoes.

Corms

• Corms are underground swollen bulb-like storage stems surrounded by dry leaves. Their physical appearance is sometimes confused with bulbs. However, they are distinguished based on the covering of the swollen structure. Bulbs only have multiple layers of dried leaves, while the internal portion of the swollen structure of corms contains solid tissue.
• The corms develop and stay dormant under unfavorable conditions. The roots and buds that arise from corms can be sprouted into new plant stems. Some examples include taro, crocus, and gladiolus.

Runners

• Runners also known as stolons are stems that grow horizontally above the ground. The runners that touch the ground create nodes from which roots and small plants are sprouted. The runners detach from the parent plant to develop a new plant. Some examples include strawberries and currants. 

Plantlets 

• Plantlets are plants that develop from the leaves of the parent plant. They sprout on the margin of the leaves containing meristem. Roots and leaves are developed as they reach maturity. An example of a plantlet is kalanchoe. 

Artificial Vegetative Propagation

• Artificial vegetative propagation is conducted in cases where the plants do not grow naturally and are therefore intervened by horticulturists and gardeners. This type of propagation produces crops with desirable qualities.
• A new plant is developed by regenerating from a piece of the parent plant. Some methods utilised for this vegetative propagation include grafting, cutting, layering, tissue culture, and suckering.

Grafting 

• Grafting is a method involved in joining a piece of stem or a single bud; called sicon, from a parent plant into another planting containing roots. This method is majorly used to grow fruit trees containing a variety of species of the same fruit in a single plant.

Cutting

• Cutting is a method where a piece such as a leaf or a stem is cut from the parent plant and grown into a new plant. Special hormones are provided to new plants at the beginning to develop roots before planting. 

Layering

• In this method, a parent plant’s stems or branches are bent until they touch the ground. These portions of stem or branches are buried in the soil. Roots are developed as layers from these portions to further grow shoots and finally develop into a new plant; this is a natural process. 

Tissue culture

• Tissue culture is a method conducted under controlled conditions, where plant cells from a parent plant are cultured in a sterilised container. This container consists of nutrients containing medium and is nurtured until the tissues are developed into a callus (a mass of cells).
• Hormones are added into the container containing callus that later develops into plantlets and finally mature into adult plants. 

Suckering

• Suckers are plants that attach to parent plants and grow. An increased number of suckers can decrease the plant size, therefore these suckers are pruned. Once the suckers mature, they are detached from the parent plant and planted separately to grow into a new plant.
• They grow new stems and roots additionally, stunting the growth of nutrient-absorbing buds that inhibits the development of the desired plant. 

Significance 

• Vegetative propagation methods are carried out to create new plants as clones of the parent plant since they share the same genetic material as that of the parent plant. Therefore, it is possible to create multiple clones of the same plant type containing desirable traits, utilised for commercial purposes.
• These techniques are capable of producing higher yields with consistent quality. The method is also cost-effective and less time-consuming since they avoid the germination stage; for example Zealong’s tea plantation. 
• In spite of these advantages, if the clones are susceptible to any disease, all the plants of the same species are affected and will lose the entire crop. Generating a gene bank for the plants and seeds to store these seeds will preserve their diversity.

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