Jim Bidlack - BIO 5354/4354 PLANT ANATOMY Lecture 13 - Phloem I. Location and function of phloem A. Found in vascular bundles and tissues in all plant parts B. Gross wood anatomy (note: phloem is the Greek word for "bark") 1. Axial system (longitudinal system) a) Sieve elements - food transport 1) Sieve cells and sieve-tube members (with companion cells) b) Sclerenchyma cells - support and some storage 1) Fibers and sclereids c) Parenchyma cells - storage 2. Ray system (cross or horizontal system) - there really isn't a phloem ray system a) Parenchyma cells - storage & radial transport C. Main functions 1. Sugar (food) transport 2. Support (to a lesser extent than xylem) D. Terms associated with phloem: "SAPS" 1. Sugar sieve cells, sieve tube members, companion cells, active, down, symplast (living) II. Primary and secondary phloem A. Primary: protophloem & metaphloem B. Secondary: secondary III. Types of Phloem (all are called "sieve elements") A.
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