Plant propagation

Plant propagation is the process by which new plants grow from a various sources, including seeds, cuttings, and other plant parts. Plant propagation can also refer to the man-made or natural dispersal of seeds. Propagation typically occurs as a step in the overall cycle of plant growth. For seeds, it happens after ripening and dispersal; for vegetative parts, it happens after detachment or pruning; for asexually-reproducing plants, such as strawberry, it happens as the new plant develops from existing parts. Plant propagation can be divided into four basic types: sexual, asexual (vegetative), layering, and grafting. Countless plants are propagated each day in horticulture and agriculture. The materials commonly used for plant propagation are seeds and cuttings. Seeds and spores can be used for reproduction (e.g. sowing). Seeds are typically produced from sexual reproduction within a species because genetic recombination has occurred. A plant grown from seeds may have different characteristics from its parents. Some species produce seeds that require special conditions to germinate, such as cold treatment. The seeds of many Australian plants and plants from southern Africa and the American west require smoke or fire to germinate. Some plant species, including many trees, do not produce seeds until they reach maturity, which may take many years. Seeds can be difficult to acquire and some plants do not produce seed at all. Some plants (like certain plants modified using genetic use restriction technology) may produce seed, but not a fertile seed. In certain cases, this is done to prevent the accidental spreading of these plants, for example by birds and other animals. Plants have a number of mechanisms for asexual or vegetative reproduction. Some of these have been taken advantage of by horticulturists and to multiply or clone plants rapidly. Humans may utilize these processes as propagation methods, such as tissue culture and grafting.