BIOL120 Lecture Notes - Lecture 11: Dendrochronology, Suberin, Pericycle

• School: University of Waterloo
• Department: Biology
• Course: BIOL120
• Professor: Susan Lolle

Document Summary

Defined as an increase in girth initiated by cell divisions in lateral or secondary meristems. Occurs in woody plants: all gymnosperms, 20% of dicots and 5% of monocots. Occurs in stems and roots after they no longer are growing in length: stems more growth than roots. New cells are added internally and bidirectionally (toward centre and surface) Vascular and cork cambium make up the lateral meristems. Primary and secondary growth happen simultaneously but in different parts of a woody plant. Apical meristems are areas of dividing cells that give rise to 3 regions of further cell differentiation: protoderm, procambium, ground meristem: protoderm: epidermis (primary dermal tissue, procambium: primary vascular tissue, ground meristem: ground tissue pith and cortex. Primary growth is growth in length, occurs in regions of cell elocation: cell elongation accompanied by dedifferentiation into different types of mature cells. Secondary meristems are cylinders, rather than clusters of undifferentiated cells: radial, increasing diameter.