AEBI 210 Lecture Notes - Taproot, Gravitropism, Mitosis
8 Jan 2013
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Document Summary
Taking in water, nutrients and minerals and storing nutrients. Very large plants have both shallow and deep roots. Shallow roots are very active, since most of the biological activity occurs in shallow soil. Deeper roots take up water and minerals from deep within the ground. Sometimes the initial taproot dies off and is replaced by fibrous roots. Fibrous root systems help to prevent soil erosion. Root cap penetrates the soil and secretes mucigel, and is the site for gravitropism. In the zone of cell division, mitosis occurs. In the zone of cell elongation cells expand. In the zone of maturation, cells differentiate for different functions. Root hairs increase the root"s surface area and form in the zone of maturation. Root cortex contains parenchyma cells with many air spaces between them. Endodermis is made up of cortex cells surrounding vascular tissue. Suberin lignifies the cell wall and middle lamella as roots mature.
