Propagating Plants Asexually Unit. Plant Science Problem Area. Plant Propagation
Asexual reproduction in plants involves the propagation of new plants using only the vegetative parts of the parent plant. Asexual propagation enables the production of a plant that would otherwise be difficult or impossible to cultivate because the plant does not produce viable seed or the seed is difficult to germinate.
Asexual = Genetic Clone maintain certain genetic forms of the plant may be faster than propagation by seed May be more economical in many cases it is easier
What are the different methods of asexual reproduction? Cuttings Stems, roots, leaves Separation Division Layering Grafting Budding tissue culture
1. A stem cutting is a cut portion of a stem that contains a terminal bud or lateral buds and is placed in growing media to produce roots. a. Softwood cuttings—from soft, succulent growth. b. Hardwood cuttings—from one-year-old growth, deciduous, or evergreen plants. c. Semi-hardwood cuttings—from woody broad-leaved plants with new shoots.
A leaf cutting consists of a leaf blade or leaf blade with petiole attached. A leaf-bud cutting consists of a leaf, petiole, and a short piece of stem with a lateral bud.
root cutting uses the root or part of the root Root cuttings are not as predictable as other cuttings, being more dependent on seasonal influences.
Rooting Temperature of the medium is kept between 75°F and 80°F High humidity with misting
Adventitious roots are roots that begin growth from the stem or a leaf
Most plants do best in a loose, well-drained growing medium
Rooting hormones can aid in rooting difficult plants
Division Vs. Separation Removal and planting of vegetative structures is separation. With division, the entire plant is cut into sections to make two or more plants
Layering is a method in which roots form on a stem while it is still attached to the parent plant
Grafting Connecting two plant parts in such a way that they will unite and continue to grow as one plant. Scion is a short piece of stem with two or more buds, and the rootstock is the lower portion of the graft. can have a dwarfing effect on the stem. increase the hardiness of a plant. Disease resistance in a plant can be improved change the natural form of a plant. to asexually propagate plants that are difficult to propagate Grafting is often used in the production of orchard trees, shade trees, and roses.
Grafting Whip-and-tongue grafting is commonly used to propagate fruit trees.
Cleft grafting is often used to join a smaller scion to a larger stock part. Bark grafting is similar to cleft grafting in that it joins smaller scion wood to a larger rootstock. Budding is similar to grafting except that the scion is reduced to a single bud with a small portion of bark or wood attached.
Tissue culture, or micropropagation, is a very technical method of asexual propagation that involves the growing of plant cells or tissues on artificial media under sterile conditions.
Advantages of Tissue Culture Large numbers of plants can be produced from a single plant in a relatively small space in a short period of time. Viruses and other systemic diseases are eliminated by propagating the quickly dividing cells of the shoot tip. Tissue culture gives the grower a means to produce plants with identical traits. Horticultural cultivars can be improved by selecting plants that vary slightly from the parent plant. Tissue culture is a required technique for producing genetically engineered plants.