Download Plant Physiology

Plant Physiology
Unit 3
Life Cycle of Plants
1. Annual – a plant that completes its life cycle in one year
2. Biennial – a plant that completes its life cycle in two years
(usually grows in the first year and flowers in the second year)
3. Perennial – a plant that lives more than two years (some will grow
and bloom in the first year)
Leaf Retention of a Plant
1. Deciduous – plants that lose their leaves during
the dormant season
2. Evergreen – plants that retain their leaves and
remain green year round
Moisture in Plants
1. Turgid – a plant that is swollen or filled with
moisture
2. Wilted – a plant that is limp because it does
not have enough moisture
Plant Growth
1. Dormant – a stage when a plant rests or grows very little
2. Plants generally go dormant in response to adverse conditions
such as extreme heat or cold
3. Botany – the part of biology that deals with plants
Season Crop Type
1. Cool season plants – relish cool temperatures, growing best in
spring or fall (ex – pansy)
2. Warm season plants – grow best in warm temperatures, growing
best in the summer and every fall (ex – zinnia, marigold, vinca)
https://youtu.be/Jns7e0fm9i0
https://youtu.be/E36JdAYb1zw
https://youtu.be/LlFl363EYac
Plant Anatomy
https://youtu.be/p3St51F4kE8
Leaves
1. External Parts
a. Petiole – the lead stalk or part that connects the leaf to the stem
b. Midrib – the large center vein
c. Blade – the large, flat part of the leaf
d. Veins – the structural framework of the leaf
e. Margin – the edge of the leaf
f. Apex – the leaf tip
Leaves
Leaves
2. Internal Parts
a.Upper and lower epidermis – the skin of the leaf that prevents the loss
of too much moisture
b.Stomates – the small openings under the leaf for breathing or
transpiration
c.Guard cells – surround the stomates and regulate the open and close
of the stomates
d.Chloroplasts – small green particles that contain chlorophyll, give
leaves their green color, and are necessary for photosynthesis
Leaves
Leaves
3. Functions of the leaf
a. Photosynthesis – process by which plants capture sunlight and
use it to convert carbon dioxide and water into food (sugar)
b. Respiration – converts sugars and starches into energy
c. Transpiration – the release of water vapor from the leaves of
plants and it helps cool the plants
Leaves
https://youtu.be/D1Ymc311XS8
Leaves
4. Leaves additional
a. Sessile describes leaves without a petiole (ex – zinnia)
b. Bracts are modified leaves (ex – poinsettia)
c. Needles and scales are modified leaves (ex – pine tree)
d. Glabrous leaves or stems have a smooth non-hairy feel (ex –
southern magnolia)
e. Pubescent leaves or stems have a hairy feel (ex – African violet)
Stems
1. External parts
a. Lenticels - breathing pores found on stems and branches
b. Bud scale scars - indicate where terminal buds have been
located
c. Leaf scars - indicate where leaves were attached
d. Terminal bud - a bud on end of stem
e. Axillary bud - the bud located at the axil of the leaf
f. Lateral buds - buds on side of stem
Stems
2. Internal parts
a. Xylem – the tissue that transports water and nutrients up from the roots
to the stem and leaves
b. Phloem – the tissue that transports food down from leaves to the roots
c. Cambium – a thin, green, actively growing tissue located between the
bark and wood and produces all new stem cells
d. Bark – old inactive phloem
e. Heartwood – old inactive xylem
f. Sapwood – new active xylem
Stems
Phloem
Phloem
Xylem
Stem
Bark
Cambium
Sapwood
Heartwood
Stems
3. Cotyledons
a. Monocots – plant systems that have vascular bundles which
contain xylem and phloem; they produce one seed leaf (ex –
grass & corn)
b. Dicots – plant stems that have a phloem layer and xylem layer
separated by cambium; they produce two seed leaves (ex – trees
& vegetables)
Stems
Xylem
Cambium
Monocot
Phloem
Dicot
Stems
4. Functions of the stem
a. Translocation – the movement of water and minerals through
the plants; the phloem moves food down from the leaves to
the roots
b. The xylem moves water and nutrients up from the roots to the
leaves
Roots
1. External parts
a. Root cap - located at the tip of the root and is where new
cells are produced
b. Root hairs – absorb moisture (water) and minerals
Roots
2. Internal parts
a. Phloem – the outer layer of the root and carries food down
the root
b. Xylem – the inner layer and carries water and minerals up to
the stem
Roots
Roots
3. Types of roots
a. Fibrous roots have many branched
shallow roots; they are easy to
transplant
b. Tap roots are long roots with few
branched ones; they are more difficult
to transplant
Roots
4. Functions of roots
a. Anchorage
b. Absorption
c. Asexual Reproduction
d. Storage
Flowers (develop into seeds & fruits)
1. External parts
a. Sepals – the green parts of the flower that cover and protect the
flower bud before it opens
b. Petals – leaves that are modified to attract insects for flower
pollination
Flowers (develop into seeds & fruit)
2. Internal parts
a. Stamens – male flower parts
• Anther – a sac like structure that contains
pollen and male sex cells
• Filament – a short stalk that holds up the
anther
Flowers (develop into seeds & fruit)
2. Internal parts
b. Pistil – female part of the flower
• Stigma – sticky pat on top of the style where insects
leave pollen
• Style – hold up the stigma and connects it to the
ovary
• Ovary – if fertilized, becomes a fruit
• Ovules – the eggs or female sex cells that become
seeds if fertilized
Flowers
Flowers
Flowers (develop into seeds & fruit)
3. Functions of the flower
a. It attracts insects for pollination
b. It produces seeds for sexual reproduction
c. It produces fruit to nourish and protect the seed
https://youtu.be/djPVgip_bdU
Flowers
4. Additional flower and fruit information
a. Complete flowers have both male and female parts
b. Incomplete flowers have only male or female parts
Flowers
Flowers
4. Additional flower and fruit information
c. Fertilization – when pollen travels down the style, joining the sperm
and the ovule
d. Pollination – the transfer of pollen from the anther to the stigma
e. Cross-pollination – the transfer of pollen from the stamen to the
stigma of one flower to a flower on another plant
f. Self-pollination – the transfer of the pollen to the stigma of a flower on
the same plant
Flowers
4. Additional flower and fruit information
g. Corolla – all auxiliary parts of the flower not including reproductive
organs; the collective term for all petals of a flower
h. Calyx – the external usually green or leafy part of a flower; also the
collective term for all sepals of a flower
i. Receptacle – the enlarged tip of a stem on which a flower is born
Flowers
4. Additional flower and fruit information
a. The fruit serves as protection for the seed
b. The function of the fruit is to help with seed dispersal
c. The juvenile stage is when a plant first begins growing from a seed