Vegetative reproduction
This article needs additional citations for verification. (March 2008) |
Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is a form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or specialized reproductive structures, which are sometimes called vegetative propagules.[1][2][3]
Many plants naturally reproduce this way, but it can also be induced artificially. Horticulturists have developed asexual propagation techniques that use vegetative propagules to replicate plants. Success rates and difficulty of propagation vary greatly. Monocotyledons typically lack a vascular cambium, making them more challenging to propagate.
Background
Plant propagation is the process of plant reproduction of a species or cultivar, and it can be sexual or asexual. It can happen through the use of vegetative parts of the plants, such as leaves, stems, and roots to produce new plants or through growth from specialized vegetative plant parts.[4]
While many plants reproduce by vegetative reproduction, they rarely exclusively use that method to reproduce. Vegetative reproduction is not evolutionary advantageous; it does not allow for genetic diversity and could lead plants to accumulate deleterious mutations.[5] Vegetative reproduction is favored when it allows plants to produce more offspring per unit of resource than reproduction through seed production.[6] In general, juveniles of a plant are easier to propagate vegetatively.[7]
Although most plants normally reproduce sexually, many can reproduce vegetatively, or can be induced to do so via hormonal treatments. This is because meristematic cells capable of cellular differentiation are present in many plant tissues.
Vegetative propagation is usually considered a
Grafting is often not a complete cloning method because seedlings are used as rootstocks. In that case, only the top of the plant is clonal. In some crops, particularly apples, the rootstocks are vegetatively propagated so the entire graft can be clonal if the scion and rootstock are both clones. Apomixis (including apospory and diplospory) is a type of reproduction that does not involve fertilization. In flowering plants, unfertilized seeds are produced, or plantlets that grow instead of flowers. Hawkweed (Hieracium), dandelion (Taraxacum), some citrus (Citrus) and many grasses such as Kentucky bluegrass (Poa pratensis) all use this form of asexual reproduction. Bulbils are sometimes formed instead of the flowers of garlic.
Mechanisms
Meristem tissue makes the process of asexual reproduction possible. It is normally found in stems, leaves, and tips of stems and roots and consists of
Another important ability that allows for vegetative propagation is the ability to develop
Advantages and disadvantages
Advantages
There are several advantages of vegetative reproduction, mainly that the produced offspring are
Vegetative reproduction offers research advantages in several areas of biology and has practical usage when it comes to
Some analyses suggest that vegetative reproduction is a characteristic which makes a plant species more likely to become invasive. Since vegetative reproduction is often faster than sexual reproduction, it "quickly increases populations and may contribute to recovery following disturbance" (such as fires and floods).[16]
Disadvantage
A major disadvantage of vegetative propagation is that it prevents species genetic diversity which can lead to reductions in crop yields.[17][18] The plants are genetically identical and are all, therefore, susceptible to pathogenic plant viruses, bacteria and fungi that can wipe out entire crops.[19]
Types
Natural means
Natural vegetative propagation is mostly a
In a sense, this process is not one of reproduction but one of survival and expansion of biomass of the individual. When an individual organism increases in size via cell multiplication and remains intact, the process is called "vegetative growth". However, in vegetative reproduction, the new plants that result are new individuals in almost every respect except genetic. Of considerable interest is how this process appears to reset the aging clock.[20]
As previously mentioned, plants vegetatively propagate both artificially and naturally. Most common methods of natural vegetative reproduction involve the development of a new plant from specialized structures of a mature plant. In addition to adventitious roots, roots that arise from plant structures other than the root, such as stems or leaves, modified stems, leaves and roots play an important role in plants' ability to naturally propagate. The most common modified stems, leaves and roots that allow for vegetative propagation are:[21]
Runners
Also known as stolons, runners are modified stems that, unlike rhizomes, grow from existing stems just below the soil surface. As they are propagated, the buds on the modified stems produce roots and stems. Those buds are more separated than the ones found on the rhizome.[22]
Examples of plants that use runners are strawberries and currants.
Bulbs
Bulbs are inflated parts of the stem within which lie the central shoots of new plants. They are typically underground and are surrounded by plump and layered leaves that provide nutrients to the new plant.[23]
Examples of plants that use bulbs are shallots, lilies and tulips.
Tubers
Tubers develop from either the stem or the root. Stem tubers grow from rhizomes or runners that swell from storing nutrients while root tubers propagate from roots that are modified to store nutrients and get too large and produce a new plant.[22]
Examples of stem tubers are potatoes and yams and examples of root tubers are sweet potatoes and dahlias.
Corms
Corms are solid enlarged underground stems that store nutrients in their fleshy and solid stem tissue and are surrounded by papery leaves. Corms differ from bulbs in that their centers consists of solid tissue while bulbs consist of layered leaves.[24]
Examples of plants that use corms are
Suckers
Also known as root sprouts, suckers are plant stems that arise from buds on the base of the parent plant's stems or roots.[25]
Examples of plants that use suckers are
Plantlets
Plantlets are miniature structures that arise from meristem in leaf margins that eventually develops roots and drop from the leaves they grew on.[26]
An example of a plant that uses plantlets is the
Keikis
Keikis are additional offshoots which develop on vegetative stems or flower stalks of several orchids genera.[14]
Examples of plants that use keikis are the
Apomixis
Apomixis is the process of asexual reproduction through seed, in the absence of meiosis and fertilization, generating clonal progeny of maternal origin.[27]
Artificial means
Vegetative propagation of particular cultivars that have desirable characteristics is very common practice. It is used by farmers and horticulturalists to produce better crops with desirable qualities. The most common methods of artificial vegetative propagation are:[21]
Cutting
A cutting is a part of the plant, usually a stem or a leaf, is cut off and planted. Adventitious roots grow from cuttings and a new plant eventually develops. Usually those cuttings are treated with hormones before being planted to induce growth.[28]
Grafting
Layering
Layering is a process which includes the bending of plant branches or stems so that they touch the ground and are covered with soil. Adventitious roots develop from the underground part of the plant, which is known as the layer. This method of vegetative reproduction also occurs naturally. Another similar method, air layering, involved the scraping and replanting of tree branches which develop into trees. Examples are Jasmine and Bougainvillea.[30]
Suckering
Suckers grow and form a dense compact mat that is attached to the parent plant. Too many suckers can lead to smaller crop size, so excess suckers are pruned, and mature suckers are transplanted to a new area where they develop into new plants.[31]
Tissue culture
In tissue culture, plant cells are taken from various parts of the plant and are cultured and nurtured in a sterilized medium. The mass of developed tissue, known as the callus, is then cultured in a hormone-ladened medium and eventually develops into plantlets which are then planted and eventually develop into grown plants.[12][32]
An offset is the lower part of a single culm with the rhizome axis basal to it and its roots. Planting of these is the most convenient way of propagating bamboo.
See also
References
- ^ "vegetative reproduction | horticulture". Encyclopedia Britannica. Retrieved 22 September 2017.
- S2CID 86138677. Retrieved 4 January 2022.
- . Retrieved 4 January 2022.
- S2CID 29297545.
- S2CID 19699365.
- PMID 28768894.
- ISBN 9789048182725.
- S2CID 11637652.
- ISBN 9781420065091.
- ^ Priestley, Joseph Hubert; Swingle, Charles F. (1929). Vegetative Propagation from the Standpoint of Plant Anatomy. U.S. Department of Agriculture.
- ^ "root | Definition, Types, Morphology, & Functions". Encyclopedia Britannica. Retrieved 2018-04-19.
- ^ JSTOR 43420451.
- JSTOR 1938188.
- ^ a b Zotz, Gerhard (1999). "Vegetative propagation in an epiphytic orchid occurrence and ecological relevance" (PDF). Ecotropica. 5.
- ^ a b Libby, W. (September 1973). "THE USE OF VEGETATIVE PROPAGULES IN FOREST GENETICS AND TREE IMPROVEMENT" (PDF). School of Forestry and Conservation and Department of Genetics. 4: 440–447.
- ^ Reichard, Sarah Hayden. "What Traits Distinguish Invasive Plants from Non-invasive Plants?" (PDF). California Exotic Pest Plant Council 1996 Symposium Proceedings.
- S2CID 35985089.
- S2CID 8274476.
- S2CID 23424978.
- ^ (General J. Grant (1864). "Vegetative Reproduction in New York: a comprehensive study. Stony Brook University Press: NY, NY.
- ^ ISBN 9780521427913.
- ^ ISBN 9780521794015.
- JSTOR 2807042.
- ISBN 978-0855642013.
- ISSN 0378-1127.
- ISSN 0304-4238.
- S2CID 656911.
- ISSN 0378-1127.
- ^ "Kumar, G. (2011). "Propagation of Plants by Grafting and Budding" (PDF). Pacific Northwest Extension. pp. 3–5" (PDF).
- ^ "Indiana Yard and Garden – Purdue Consumer Horticulture - Purdue University". Indiana Yard and Garden - Purdue Consumer Horticulture. Retrieved 2018-04-20.
- ISSN 0008-4026.
- ^ Reilly, Kathryn (4 April 1977). "VEGETATIVE PROPAGATION OF RADIATA PINE BY TISSUE CULTURE: PLANTLET FORMATION FROM EMBRYONIC TISSUE" (PDF). Forest Research Institute, New Zealand Forest Service, Rotorua. 7: 199–206.