BIOL120 Study Guide - Adventitiousness, Root Hair, Root System
13 Mar 2014
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Document Summary
Typical of dicots and gymnosperms (develops directly from embryonic root) Taproots penetrate deeply although conifers generally do not. Small plants can have significant taproot systems. Taproots can enhance survival in harsh environments (drought tolerance) Typical of monocots and svps (embryonic root dies) Root system arises from lower part of stem: therefore adventitious. After the radicle/embryonic root dies, numerous roots form from the lower part of the stem called adventitious roots. Often found in annuals (plants that have only a one year growing season) Root systems can vary in depth and length: Typically 50-90% occurs in the top 30 cm of soil. Length of root system can be far greater than shoot system (corn: 457 meters root to 2. 5 meters) Grows from tip (downwards) and matures in a retrograde manner (upwards) A supply of dividing cells are found at the tip of the root. This region is known as the root apical meristem ( fountain of youth )
