Download Bio Notes Plant Anatomy Stem Transport

The Four Basic Parts of Plants
 Leaves
 Stems
 Roots
 Flowers
Stems: Transport
Plant Structure:


Organs: Roots, Stems (trunks) and
leaves
Tissues: a group of cells working
together to perform a certain task
Stems

Mostly above ground

Except: Potatoes and ginger are
underground stems
Stems

Functions



Support flowers & leaves
Movement of materials: Vascular System
Stores food and water
Internal Stem Structure

Vascular Tissue

Made of hollow tubes
Internal Stem Structure

Vascular Tissue

1. Xylem: carries
water and nutrients
up from the roots to
the rest of the plant.
Internal Stem Structure

Vascular Tissue
2. Phloem: carries
sugars produced
by photosynthesis
from leaves to the
rest of the plant.
Internal Stem Structure

Xylem
 Water and dissolved minerals move up
from the roots to the rest of the plant.
 Cohesion and Adhesion: physical
properties of water (Hydrogen bonding)
allows water to rise through the plant
Transport
Cohesion (“co”-together, “haerere”-to
cling): strong attraction between water
molecules to each other.
 Adhesion: attraction of water
molecules for other surfaces (such as
water molecules for the wall of the
xylem tissue)

Transport

Capillary Action: tendency of water to
move upward in a hollow tube.

Caused by tension created by cohesion and
adhesion
Transport

Transpiration: Loss of water,
“evaporation” from leaves (high to low
concentration)

Outward flow of water (out of plant)
causing a vacuum, pulling water upward.
Internal Stem Structure

Phloem
 Example: sap (fluid): products of
photosynthesis move from leaves to stems
and roots.
 Minerals traveling up can also move
here.
Internal Stem Structure

Phloem
 Sugar source: high concentration of sugar
(leaves, can be roots)
 Sugar sink: uses or stores sugar

Growing shoots and stems, fruits, storage roots
Herbaceous vs Woody

Herbaceous: soft, low growing, green
and conduct photosynthesis

Monocot or Dicot
Herbaceous vs Woody

Woody:

Tree trunks-dicots

Center: Hardwood: oldest part


Support
 No transport
Sapwood:


Around heartwood
Does transport water
Tree Rings

Each Annual Ring:


Includes both a light and dark ring:
represents one year of growth
Evidence of the age of tree: count the
number of rings
Tree Rings

Tells us how much tree grew each
season

Good supply of water in spring:


Cells are wide and have thin walls  light in
color
Water limited:

Cells smaller and thicker walls 
darker in color