Natural cloning in plants

Natural cloning

• Vegetative propagation = natural cloning
• A structure forms which develops into a fully differentiated new plant which is genetically identical to parent
• Often involves perennating organs which enables the plant to survive adverse conditions
• They have stored food from photosynthesis and can remain dormant in the soil
• Bulbs -->  leaf bases swell with stored food and the buds form internally which develop into new shoots and plants when the next growing season arrives
• Runners --> a lateral stem grows away from the parent plant and roots develop wherever the stem touches the soil, a new plant develops and the runner withers away
• Rhizomes --> specialised horizontal stem that runs underground often swollen with stored food, buds develop and form new vertical shoots which become independent plants
• Stem tubers --> tip of underground stem becomes swollen with food or to form a storage organ, buds on storage organ develop into new shoots

Using natural cloning in horticulture

• Splitting up bulbs, removing young plants from runners and cutting up rhizomes are all ways to increase plant numbers cheaply --> new plants genetically identical to parents
• Take cuttings of a plant --> short sections of stems can be planted directly or in pots
• Rooting hormone is often applied to the base of a cutting to encourage the growth of new roots
• Cutting are faster than using seeds and the time from planting to cropping is reduced 
• It also guarantees the quality of the plant
• The main drawback is the lack of genetic variation so a new disease or pest could kill them all

Cloning sugar cane

• Internationally important crop to make sugar and biofuels
• Short lengths with 3 nodes are cut and buried in a clear field of shallow trenches then covered with soil 
• Per hectare 10-25,000 lengths of stem can be planted