Transcript Roots, Stems, & Leaves

 3 Main Tissues:
 Dermal Tissue: epidermal cells; outer covering
of plant, like skin
 Vascular Tissue: contains xylem with tracheid
cells & phloem
 Ground Tissue: cells between the dermal and
vascular; have three types of cells
 Parenchyma: thin cell walls
 Collenchyma: strong flexible cell walls
 Sclerenchyma: extremely thick, rigid cell walls
 Two Type of Roots
 Taproots: found in dicots; grow long & thick;
reach water far below
 Fibrous Roots: have many branching roots of
same size
 Structure = epidermis on outside,
vascular tissues in middle, & ground
tissues in middle
 Root Hairs: extensions that allow roots
to absorb more water
 What is their job:
 Uptake nutrients and water
 Move nutrients to plant & vascular tissues
 Keep high pressure to move water & nutrients
up the plant
 Three important functions:
 Produce leaves, branches, & flowers
 Leaves connected at Nodes & start as Buds
 Hold leaves up to the sunlight
 Transport substances from roots to leaves
 Monocot vs Dicot Stems
 Monocot = dispersed vascular bundles
 Dicot = vascular bundles in circle
 Wood is layers of xylem
 Heartwood = middle of tree that no
longer has water flowing through it
 Sapwood = surround the heartwood &
transports water through xylem
 Bark = outer layer of stem
 Purpose: to absorb sunlight and
perform photosynthesis
 Green color because of chlorophyll
 Blade: flattened section; collects sunlight
 Petiole: stalk that blade attaches to
 Photosynthesis occurs in mesophyll
 Palisade mesophyll: cells that absorb light
 Spongy mesophyll: has air sacs connected to
stomata
 Stomata: pore-like structures that allow carbon dioxide
and oxygen to enter and leave the leaf
 Guard Cells: two of these cells make 1 stomata
 Stomata stay open during photosynthesis, but close
when losing too much water