Dwarfing
Encyclopedia
Dwarfing is a characteristic in plants and animals whereby one or more members of a breed
or cultivar
are significantly smaller than standard members of their species. The effect can be induced through genetic or hormonal means.
, genetic engineering
, selective breeding
, and insular dwarfism
. Dwarfing can produce more practical breeds that can fit in small accommodations, as well as other associated benefits.
As with animals, plants can be dwarfed through genetic engineering
and selective breeding
, but can also undergo natural, morphological changes to acclimatize to environmental stresses such as soil quality, light, drought, flood, cold, infection, and herbivory
resulting in a dwarfed stature. Plants dwarfed due to environmental stress are said to be "stunted
." The majority of dwarfing in plants occurs not from the damage environmental stresses inflict on them, but instead by hormones produced in response to the stress. Plant hormone
s act as a signal to the various tissues of plants inducing one or more responses, the class of plant hormone
responsible for dwarfing in plants due to injury are called jasmonate
s. Such responses include, but are not limited to: less frequent cell divisions and reduction of cell elongation.
The propagation of decorative, dwarfed plants, known as bonsai
, can occur by providing artificial environmental stress.
In horticulture
, dwarfing can be considered a desirable characteristic in modern orchard
s. This kind of dwarfing can be attained through selective breeding
, genetic engineering
, or more often, scions are graft
ed on to dwarfing rootstocks. Almost all modern apple
s in commercial use are propagated as dwarf or semi-dwarf trees for ease of picking and spraying.
Breed
A breed is a group of domestic animals or plants with a homogeneous appearance, behavior, and other characteristics that distinguish it from other animals or plants of the same species. Despite the centrality of the idea of "breeds" to animal husbandry, there is no scientifically accepted...
or cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
are significantly smaller than standard members of their species. The effect can be induced through genetic or hormonal means.
Animals
In animals, including humans, dwarfing can occur in several ways resulting from growth hormone deficiencyGrowth hormone deficiency
Growth hormone deficiency is a medical condition in which the body does not produce enough growth hormone . Growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction...
, genetic engineering
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...
, selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
, and insular dwarfism
Insular dwarfism
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of the reduction in size of large animals – typically mammals – when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf...
. Dwarfing can produce more practical breeds that can fit in small accommodations, as well as other associated benefits.
Plants
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...
and selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
, but can also undergo natural, morphological changes to acclimatize to environmental stresses such as soil quality, light, drought, flood, cold, infection, and herbivory
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
resulting in a dwarfed stature. Plants dwarfed due to environmental stress are said to be "stunted
Stunt (botany)
In botany and agriculture, stunting describes a plant disease that results in dwarfing and loss of vigor. It may be caused by infectious or noninfectious means.-Infectious:A stunt caused by infectious means usually is too late to cure.* Nematodes...
." The majority of dwarfing in plants occurs not from the damage environmental stresses inflict on them, but instead by hormones produced in response to the stress. Plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
s act as a signal to the various tissues of plants inducing one or more responses, the class of plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
responsible for dwarfing in plants due to injury are called jasmonate
Jasmonate
Jasmonate and its derivatives are lipid-based hormone signals that regulate a wide range of processes in plants, ranging from growth and photosynthesis to reproductive development. In particular, JAs are critical for plant defense against herbivory and plant responses to poor environmental...
s. Such responses include, but are not limited to: less frequent cell divisions and reduction of cell elongation.
The propagation of decorative, dwarfed plants, known as bonsai
Bonsai
is a Japanese art form using miniature trees grown in containers. Similar practices exist in other cultures, including the Chinese tradition of penjing from which the art originated, and the miniature living landscapes of Vietnamese hòn non bộ...
, can occur by providing artificial environmental stress.
In horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
, dwarfing can be considered a desirable characteristic in modern orchard
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...
s. This kind of dwarfing can be attained through selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
, genetic engineering
Genetic engineering
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest...
, or more often, scions are graft
Grafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...
ed on to dwarfing rootstocks. Almost all modern apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
s in commercial use are propagated as dwarf or semi-dwarf trees for ease of picking and spraying.
See also
- Miniature
- Fruit tree propagationFruit tree propagationFruit tree propagation is usually carried out through asexual reproduction by grafting or budding the desired variety onto a suitable rootstock.Perennial plants can be propagated either by sexual or vegetative means...
- Habit (biology)Habit (biology)Habit, when used in the context of biology, refers to the instinctive actions of animals and the natural tendencies of plants.In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology...
- Insular dwarfismInsular dwarfismInsular dwarfism, a form of phyletic dwarfism, is the process and condition of the reduction in size of large animals – typically mammals – when their population's range is limited to a small environment, primarily islands. This natural process is distinct from the intentional creation of dwarf...