Transcript Unit B. 3.0 Plant Physiology

Horticulture I
3.00 Plant Anatomy
Mrs. Schratwieser
Unit B Plant Physiology
• 3.01 Discuss biological terms used to describe
plants.
A. Life Cycle of Plants
1. Annual –completes its life cycle in 1 year
2. Biennial – completes its life cycle in 2 years
• Usually grows the 1st and flowers the 2nd
3. Perennial – lives more than 2 years
• Some grow and bloom the first year
B. Leaf Retention of a Plant
1.
Deciduous – lose their leaves during dormant season
2.
Evergreen – plants retain their leaves and remain green year round
C. Moisture in Plants
1.
Turgid – swollen with moisture
2.
Wilted – plant is limp because it does not have enough moisture
D. Plant Growth
1.
Dormant – resting or growing very little
• Generally a response to adverse conditions (extreme heat or cold)
2.
Botany – plant part of biology
E. Season Crop Type
1.
Cool season plants – relish cool temperatures
• Grow best in spring or fall
• Pansy
2.
Warm season plants – relish warm temperatures
• Grow best in summer and early fall
• Zinnia, Marigold, Vinca
Plant Physiology
• 3.02 Discuss the anatomy and functions of
plants
A. Leaves
External Parts of Leaf
• Petiole
• Midrib
• Blade
• Veins
• Margin
• Apex
Petiole
(leaf stalk-connects leaf
to stem)
Midrib- large center vein
Blade-large, flat part of leaf
Veins-structural framework
of leaf
Margin – edge of leaf
Apex- leaf tip
Internal Parts of leaf
• Epidermis
• Stomates
• Guard cells
• Chloroplasts
Epidermis – “skin” part of
leaf prevents water loss
Stomates – small openings
under the leaf that allow the
plant to breath or transpire
Guard Cells – regulate the
opening and closing of
stomates
Chloroplasts – small green
particles (chlorophyll)
needed for photosynthesis
Functions of Leaf
• Photosynthesis
• Respiration
• Transpiration
Photosynthesis-process of
capturing sunlight to convert carbon dioxide
and water into food
6 CO2 + 6 H2O → 6(CH2O) + 6 O2
Respiration- converts sugars
and starches into energy
Transpiration – release of
water vapor from leaves
(cools the plants)
Leaves additional
• Sessile
• Bracts
• Needles & Scales
• Glaborous
• Pubescent
Sessile-leaves without a
petiole (Zinnia)
Bracts – modified leaves
(poinsettia)
Needles & Scales – modified
leaves (pine tree, cedar)
Glaborous – leaves/stems with
a smooth, non hairy feel
(magnolia)
Pubescent – leaves/stems
with hairy feel (fuzz)
(African Violet)
B. Stems
External Parts
• Lenticels
• Bud scale scars
• Leaf scars
• Terminal bud
• Axillary bud
• Lateral bud
Lenticels
• Breathing pores
• On stems and branches
Bud Scale Scars
• Indicates where a terminal bud has been located
Leaf Scar
• Indicates where a leaf was attached
Terminal Bud
• Bud on end of stem
Axillary bud
• Bud located at the axil of the leaf
Lateral Bud
• Buds on side of stem
Internal parts of stem
• Xylem
• Phloem
• Cambium
• Bark
• Heartwood
• Sapwood
Internal Stems
1.
Xylem - Tissue transporting water and nutrients up from the roots to the
stems and leaves
2.
Phloem – Tissue transporting food down from leaves to the roots
3.
Cambium – Thin, green, actively growing tissue between the bark and wood
• Produces all new stem cells
4.
Bark – Old, inactive phloem
5.
Heartwood – Old, inactive xylem
6.
Sapwood – New, active xylem
Cotyledons
1.
Monocots – plant stems with vascular bundles
• Each bundle contain both xylem and phloem
• Produce one seed leaf
• Many grasses and corn
2.
Dicots – plant stems have a phloem and xylem layer separated by cambium
• Produce 2 seed leaves
• Trees and many vegetables
Functions of the stem
1.
Translocation – movement of water and minerals through plant
• Phloem moves food down to roots
• Xylem moves water & nutrients up to leaves from roots
C. Roots
External parts (much different than stems)
1.
Root cap – located at tip of root
• Where new cells are produced
2.
Root hairs – absorb moisture (water) and minerals
Internal Parts (much like stems)
• Contain phloem, cambium, xylem layers
1.
Phloem – outer layer of root, carries food down the root
2.
Xylem- inner layer of root, carries water and minerals up to stem
Types of roots
1.
Fibrous – many branched shallow roots
• Easy to transplant
2.
Tap – long roots with few branched roots
• More difficult to transplant
Functions of Roots
1.
Anchorage
2.
Absorption
3.
Asexual reproduction
4.
storage
D. Flowers
External
• Sepals – green parts that cover and protect flower bud before it opens
• Petals – really modified leaves that attract insects for polination
Internal
• Develop into seeds & fruits
• Stamens – Male flower part
1.
Anther: sac-like structure, contains pollen (male sex cells)
2.
Filament: short stalk, holds up anther
• Pistil – Female flower part
1.
Stigma: sticky part on top of style, where pollen is deposited
2.
Style: holds up stigma, connects it to the ovary
3.
Ovary: becomes fruit if fertilized
4.
Ovules: eggs (female sex cells) becomes seeds if fertilized
Functions
• Attracts insects for pollination
• Produces seeds for sexual reproduction
• Produces fruit to nourish and protect seed
Additional Information
• Complete flower – contains male and female parts
• Incomplete flower – have only male or only female parts
• Fertilization – pollen travels down the style, joining sperm and ovule
• Pollination – transfer of pollen from anther to stigma
• Cross-pollination – transfer of pollen from stamen to stigma of one flower to a
flower on another plant
• Self-pollination – transfer of pollen from stamen to stigma of a flower on the
same plant
Additional Information
• Corolla – auxiliary parts of the flower, not including reproductive organs
(collective term for all the petals of flower)
• Calyx – external, usually green, leafy part of the flower (collective term for all
sepals of a flower)
• Receptacle – enlarged tip of a stem on which a flower is born
• Fruit – protects seed & helps with seed dispersal
• Juvenile stage – plant first begins to grow from a seed
Read and summarize “Why leaves Change Color”
• http://www.buzzle.com/articles/why-do-leaves-change-color.html