Roots Section 12.4

Roots Learning Goal: To explore the structure and function of plant roots. Success Criteria: I know I am succeeding when I can… describe the features of taproot and fibrous root systems explain the differences and similarities between monocot and eudicot roots describe the nature, structure, and function of different specialized roots list a variety of ways that humans use roots

Roots anchor the plant and keep it upright absorb water and nutrients from the soil may store water and carbohydrates

Types of Root Systems taproot system has a large, thick, main root called a taproot, which grows straight downward push deep into the soil gymnosperms and angiosperm eudicots have taproot systems

Types of Root Systems Cont’d… fibrous root system has many small roots tend to be shallower than taproots occur in angiosperm monocots Both root systems have root hairs and can have lateral branching

Structure of Roots the tip of the root contains: root cap: a thick layer of cells that produce a slippery substance to help the root penetrate the soil, minimizing damage to the root cells Meristem: produces new cells to increase the length of the root

Structure of Roots Cont’d… root hairs above the root tip project out of the epidermis and increase the surface area for absorption root cortex is a region of parenchyma cells beneath the epidermis that stores carbohydrates and helps transport water from the epidermis to the xylem walls of the cells in the endodermis are wrapped with a wax-like substance, forming a continuous barrier called the Casparian strip

Structure of Roots Cont’d… vascular cylinder contains the vascular tissue of roots in gymnosperms and eudicots, the centre of the root contains xylem cells forming an “X” or star-shape in the centre of the vascular cylinder the phloem cells are also in the centre of the root, around the xylem arrangement of xylem and phloem within the vascular cylinder varies among the groups of angiosperms

Structure of Roots Cont’d… in monocots the centre of the root contains parenchyma cells surrounded by a ring of xylem cells and a ring of phloem cells

Roots Learning Goal: To explore the structure and function of plant roots. Success Criteria: I know I am succeeding when I can… describe the features of taproot and fibrous root systems explain the differences and similarities between monocot and eudicot roots describe the nature, structure, and function of different specialized roots list a variety of ways that humans use roots

Homework Answer 12.4 questions #7, 9 & 10 on page 563