CHAPTER 33

CHAPTER 33 - CHAPTER 33 LEAF STRUCTURE AND FUNCTION...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER 33 LEAF STRUCTURE AND FUNCTION Photosynthesis o Biological process that converts radiant energy into the chemical energy of carbohydrate molecules o Takes place in the leaves LEAF FORM AND STRUCTURE Anatomy of leaf o Blade Broad, flat portion of a leaf o Petiole Stalk that attaches the blade to the stem o Stipules Leaflike outgrowths usually present in pairs at the base of the petiole Types of leaves o Simple leaf Has a single blade o Compound leaf Has a blade divided into two or more leaflets Can tell it is a compound leaf if there are no axillary buds Bud that develops at the axil (angle between the stem and the petiole Leaf Arrangement o Node The area of the stem where one or more leaves are attached o Alternate leaf arrangement One leaf located at each node Ex: Beeches and walnuts o Opposite leaf arrangement Two leaves grow at each node Ex: maples and ashes o Whorled leaf arrangement Three or more leaves grow at each node Ex: catalpa trees Vein arrangement o Veins Strands of vascular tissue o Parallel venation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Veins run approximately parallel to one another Characteristic of monocots o Netted Venation Veins are branched in such a way that they resemble a net Characteristic of eudicots Midvein o Main or central vein of a leaf Pinnately Netted Major veins branching off in succession along the entire length of the midvein Palmately netted Several major veins radiating out from one point See figure 33-2, Page 717 Leaf structure consists of an epidermis, photosynthetic ground tissue, and vascular tissue Internal Structure of leaves o Upper epidermis and lower epidermis Covers the upper surface and lower surface of the leaf Cells lack chloroplasts and are relatively transparent Cell wall facing toward the outside environment is thicker than the cell wall facing inward Secrete a waxy layer called a cuticle Helps reduce water loss from the exterior walls of epidermal cells Consists primarily of a waxy substance called cutin Upper epidermis generally has a thicker cuticle than the lower epidermis Covered with trichomes Various hairlike structures Serve a variety of functions that help support the leaf Contains minute openings called stomata Used for gas exchange between leaf cells and the environment Evenly spaced to optimize this gas exchange Flanked by two specialized guard cells o Responsible for opening and closing the stoma o The only epidermal cells with chloroplasts o Associated with special epidermal cells called subsidiary cells Often structurally different from other epidermal cells Provide a reservoir of water and ions that move into and out of the guard cells as they
Background image of page 2
change shape during stomatal opening and closing o Mesophyll Photosynthetic ground tissue of the leaf Sandwiched between the upper epidermis and lower epidermis Parenchyma cells packed with chloroplasts, loosely arrange, with
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/04/2008 for the course BIO 101 taught by Professor Martin during the Fall '08 term at Rutgers.

Page1 / 8

CHAPTER 33 - CHAPTER 33 LEAF STRUCTURE AND FUNCTION...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online