Transcript Vegetative Parts

Vegetative Parts
The main vegetative organs of plants
that we will be talking about are
• Roots
• Stems
• Leaves
• Vegetative parts of plants that we eat for
nourishment are known as vegetables
Plant Tissues
Ground Tissue Types
Meristem Tissue
Plants Need
1. Oxygen
2. Carbon Dioxide
3. Sunlight
4. Water
5. Nutrients (essential elements)
Why? You ask……..
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Photosynthesis
Respiration
Growth
Development
Reproduction
Plant
parts.
Crown (leaf area)
Trunk (stem)
Roots
Crown (leaf area)
Branches
Twigs
Leaves
Flowers
Fruit (seeds)
Crown (leaf
area)
Captures sunlight and carbon
dioxide (for photosynthesis) ,
regulates water loss
(transpiration), has reproduction
organs and produces seeds.
Transpiration moves water
and essential elements through a
plant.
Photosynthesis is a
primary function
in plants
CO2 + H2O ----- CH2O + H2O + O2
Note: sugar.
Respiration is the burning
of nutrients for energy by
the cells
Note: sugar.
All parts of plant carry on respiration
Let’s look at the 3 main plant
organs in more detail
• Leaves
• Stems
• Roots
Leaf
Cuticle
• Waxy layer
• Controls water loss by “waterproofing” the
leaf
• Upper and lower
Epidermis
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Protects the leaf surface
It is the “skin” of the leaf
Holds in moisture also
Upper and lower
Control gas entry/exit in leaves
Mostly in lower epidermis !
Stomata, Pea Leaf Stoma, Vicea sp. (SEM x3,520).
Mesophyll
• Cells with chloroplasts filled with
chlorophyll that carry out photosynthesis
– Palisade cells are long, upright, erect, and
packed like sardines. Most photosynthesis
takes place here.
– Spongy cells are rounded and irregular and
loosely packed with a lot of air spaces for
movement of gases. Less photosynthesis
here because there are fewer chloroplasts.
Veins
• Bundles of vascular tissue
– Xylem carrying water and nutrients to leaf
cells
– Phloem carrying food to storage sinks
– Sheathing cells to enclose and protect the
vascular tissue
Trunk(stem)
Heartwood
Xylem
Cambium
Phloem
Bark
Trunk, (stem)
Transports water, food and
other essential elements,
stores energy, elevates and
displays leaves to sun
Woody
(Dicot)
(monocot)
Herbaceous
In woody stems, the
vascular cambium
produces phloem on
the outside (next to
the bark) and xylem
on the inside. Old
xylem is the “wood”
and exhibits the
annual rings of growth
Roots
Roots
Collect water and
essential elements,
anchor plants, store
food.
Roots
Root branches (tap
root, clustered and
fibrous roots)
Root hairs
Taproot – one main vertical root
and branches from it
Fibrous roots – many branches of
about the same size/length; like the
grasses
Fascicled/clustered roots – similar
to fibrous but of many varying sizes
Vascular tissue arrangement varies
Dicot root
Monocot root.
Roots
1. 95% of roots in top foot of
soil.
2. Biggest limiting factor to
root growth is oxygen.
3. Roots often extend three
times the distance of the
branches.
Water is absorbed
by diffusion into the
root hairs then to
the xylem of the
root. It is then
moved by cohesion
of water molecules
and capillary action
up the stem xylem
Ideal Soil
A) mineral material
45%
B) air
25%
C) water
25%
D) organic material
5%
note:
air + water = pore space
or
25% + 25% = 50% pore space
Remember roots carry on
respiration so they need
oxygen, too.
Stress
Stress occurs often occurs when a plant won't
get enough of what it needs. . .
Sunlight, water, essential elements, oxygen to
roots etc.
Transport in Plants