2. Anatomy & Physiology of Medicinal Plants
This unit will be covered under the following subject
topics:
◼ Anatomy: An Overview, The Protoplast, Cell Wall, Meristems,
Parenchyma, Collenchyma, Sclerenchyma, Epidermis, Xylem, Phloem,
Vascular Cambium, Periderm and Secretory Structures
◼ Physiology: An Overview, Plant Cells , Nutrient Uptake, Inorganic
Nutrients, ATP Synthesis, Role of Sunlight, Harvesting Sunlight, CO2
Assimilation, Photo assimilates, Energy Storage & release, Nitrogen
Assimilation, Carbon and Nitrogen Assimilation , Environmental Stress,
Hormones, Photomorphogenesis, Tropisms & Nastic Movements,
Measuring Time, Flowering & Fruit Development, Temperature effect and
Secondary Metabolites
5. Plant Parts Anatomy
◼ Plant anatomy or phytotomy is the general term for the study of the
internal structure of plants. While originally it included plant morphology,
which is the description of the physical form and external structure of
plants, since the mid-20th century the investigations of plant anatomy are
considered a separate, distinct field, and plant anatomy refers to just the
internal plant structures. Plant anatomy is now frequently investigated at
the cellular level, and often involves the sectioning
of tissues and microscopy.
6.
7.
8.
9. The Four Basic Parts of Plants
◼ Leaves
◼ Stems
◼ Roots
◼ Flowers
What are the different parts of plants and how do they function?
10.
11. Leaves
◼ Functions
◼ Make food through photosynthesis
◼ Site of gas exchange
◼ Respiration
◼ Photosynthesis
◼ Store food
◼ Help in identification of plant
12. What are the parts of the
leaf?
◼ Petiole-leaf stem or stalk
◼ Blade-large flat structure used to capture light
◼ Midrib-largest vein in center of leaf
◼ Veins-tiny tubes that form patterns in the leaf blade, move
water, minerals, nutrients in and out of leaf
◼ Leaf margin-outer edge of the leaf
◼ Leaf apex-tip of the leaf
◼ Leaf base-part of blade attached to the petiole
◼ Leaf covering-can be waxy or hairy
◼ Stomata-pores that take in and release gases and water
vapor
13. What are the types of leaves?
◼ Simple leaves
◼ Consist of a single leaf blade and petiole
◼ Compound leaves
◼ Consist of petiole and two or more leaf
blades called leaflets
◼ To identify, look for the axillary bud
◼ Leaflets do not have axillary buds
◼ If no axillary bud, then compound leaf
14. How are leaves arranged?
◼ In patterns
◼ Opposite-two leaves and buds are directly
across from each other
◼ Alternate-leaves and buds are staggered
along stem
◼ Whorled-three or more leaves and buds
arise from same point in the stem
15. Leaf Color and Texture
◼ Determined by pigments
◼ Green=chlorophyll
◼ Absorbs light, needed for photosynthesis
◼ Orange/yellow=carotene
◼ Yellow to none= Xanthophyll
◼ Blue/purple/red=Anthocyanins(flowers)
◼ Yellow/cream= Flavonols (flowers)
◼ Chlorophyll masks other colors
◼ Not seen until chlorophyll dies or is in lower
concentrations, ex. Fall
16. ◼ Variegation
◼ Different color patterns on the leaves
◼ Ex. Coleus, prayer plant, caladium
◼ Bracts
◼ Modified leaves with petal-like appearance
◼ Ex. poinsettia
17. Tissues of the Leaf (Epidermis)
◼ Cuticle
◼ Waxy substance that
covers the leaves &
stems
◼ Waterproof layer
that keeps water in
plants
18. Tissues of the Leaf (Epidermis)
◼ Stomata
◼ Openings in the
epidermis mainly
located on the
underside of leaves
◼ Exchange of gases
19. Tissues of the Leaf (Epidermis)
◼ Guard Cells
◼ Two cells located on
each side of stomata
◼ Open and closes
stomata
20. Tissues of the Leaf
(Mesophyll Layer)
◼ Palisade mesophyll
◼ Primary site of photosynthesis
◼ Spongy mesophyll
◼ Contains air & chloroplasts
◼ Site of photosynthesis and gas exchange
21. Tissues of the Leaf
◼ Vascular Bundles
◼ Called veins
◼ In spongy mesophyll
◼ Phloem moves food
from leaf to the rest
of the plant
◼ Xylem moves water
& minerals up to
leaves from roots
23. External Parts of the Leaf
◼ Petiole
◼ Leaf stalk or part that connects the leaf to
the stem.
◼ Blade
◼ The large, flat part of a leaf.
◼ Midrib
◼ The large center vein.
31. Examples of Medicinal Leaves
◼ Alfalfa (Medicago sativa) leaves are used to lower cholesterol, as well as
for kidney and urinary tract ailments, although there is insufficient scientific evidence
for its efficacy.
◼ Aloe vera leaves are widely used to heal burns, wounds and other skin ailments.
◼ Chaparral (Larrea tridentata) leaves and twigs are used by Native Americans to make
an herbal tea used for a variety of conditions, including arthritis, cancer and a number
of others. Subsequent studies have been extremely variable, at best. Chaparral has
also been shown to have high liver toxicity, and has led to kidney failure, and is not
recommended for any use by the U.S. Food and Drug Administration (FDA)
or American Cancer Society.
◼ Eucalyptus (Eucalyptus globulus) leaves were widely used in traditional medicine as
a febrifuge. Eucalyptus oil is commonly used in over-the-counter cough and cold
medications, as well as for an analgesic.
◼ Grape (Vitis vinifera) leaves and fruit have been used medicinally since the ancient
Greeks.
◼ Ginkgo (Ginkgo biloba) leaf extract has been used to treat asthma, bronchitis, fatigue,
and tinnitus
34. Stems
◼ Functions
◼ Movement of materials
◼ Water & minerals from roots to leaves
◼ Manufactured food from leaves to roots
◼ Support leaves & reproductive structures
◼ Food storage organ
◼ Green stems make food
35. What are the parts of the
stem?
◼ Terminal bud- contains undeveloped leaf, stem, or
flower
◼ Bud scale- tiny leaf like structures that cover the bud
◼ Axillary bud- produce new leaf along side of stem
◼ Node- point where leaves or other stems attach
◼ Leaf scar- scar left when leaf drops
◼ Lenticel - tiny pores located on stem that allows for
gas exchange
36. What is the internal structure of the
stem?
◼ Xylem- conductive tissue in stem that
transports water and minerals from
roots to leaves
◼ Also provides structural support
◼ Phloem- transports food from the
leaves to the rest of the plant
37. External Stem Structure
◼ Lenticels
◼ Breathing pores.
◼ Bud Scale Scars
◼ Show where terminal buds have been
located.
◼ Leaf Scars
◼ Show where leaves were attached.
38. External Stem Structure
◼ Terminal Bud
◼ Bud on the end of the stem.
◼ Axillary Lateral Bud
◼ Bud on the side of the stem.
40. Internal Stem Structure
◼ Xylem
◼ The tissue that transports water & nutrients up
from roots to stems & leaves.
◼ Phloem
◼ Tissue that transports food down from leaves to
roots.
◼ Cambium
◼ Thin, green, actively growing tissue located
between bark & wood and produces all new stems
cells.
46. What are specialized stems?
◼ Bulbs- short, flattened stems that have
fleshy food storage leaves
◼ Rhizome-underground horizontal stem
◼ Stem tubers- swollen tips of a rhizome
(ex. Irish potato)
◼ Stolen- above ground horizontal stems
◼ Others – Various forms include those in
water
47. Specialized Types of Stems
◼ Bulb
◼ Layers of fleshy
scales that overlap
each other
◼ Underground stem
◼ Examples
◼ Tulips
◼ Lilies
◼ Onions
48. Specialized Types of Stems
◼ Rhizomes
◼ Underground stems
that produce roots
on the lower surface
and extend leaves
and flower shoots
above ground
◼ Examples
◼ Iris
◼ Lily of the Valley
58. Roots
Functions
◼ These are whitish or tan (chocolate / coffee) in color
◼ Make up one-half or more of the entire plant body
◼ Absorb water and nutrients from the soil and transport
them above ground
◼ Serve to anchor and support the top portion on plant
◼ Can store carbohydrates to be used later for energy by
plant
59. What are the parts of a root system?
◼ Primary root- first structure to emerge from
germinating seed
◼ Secondary root- arises from the primary root
◼ Don’t transplant seedlings or cuttings until after
secondary root forms
◼ Root hairs- single cell roots located a few mm
back from root tip, absorb water
◼ Root cap- mass of cells that protects root tips
from coarse soil
60. What are the differences between
taproot and fibrous root systems?
◼ Taproot
◼ One large primary root that grows down
+ small secondary roots
◼ Fibrous root
◼ Root develops into a number of small
primary and secondary roots
◼ Grow shallow near the soil line
◼ Subjected to drought and mineral
deficiencies
◼ Most landscape plants
61. Different Types of Roots
◼ Tap Root
◼ One main root, no
nodes
◼ Continuation of the
primary root
◼ Ideal for anchorage
◼ Penetration is
greater for water
◼ Storage area for food
62. Different Types of Roots
◼ Fibrous Root
◼ Many finely branched
secondary roots
◼ Shallow roots cover
a large area
◼ More efficient
absorption of water &
minerals
◼ Roots hold the soil to
prevent erosion
63. Different Types of Roots
◼ Aerial Roots
◼ Clinging air roots
◼ Short roots that grow
horizontally from the
stems
◼ Roots that fasten the
plant to a support
◼ Absorptive air roots
◼ Absorb moisture from
the air
64. Different Types of Roots
◼ Adventitious Roots
◼ Develop in places
other than nodes
◼ Form on cuttings &
rhizomes
66. External Parts of Roots
◼ Root Hairs
◼ Tiny one celled hair-
like extensions of the
epidermal cells located
near the tips of roots.
◼ Increase surface area.
◼ Absorb water &
minerals.
67. Internal Parts of Roots
◼ Much like those of stems with phloem,
cambium and xylem layers.
◼ Phloem
◼ The outer layer.
◼ Carries food down the plant.
◼ Xylem
◼ The inner layer.
◼ Carries water & minerals up to the stem.
68. What are modified roots?
◼ Adventitious roots
◼ Begin growing from stem or leaf
◼ Grow from cuttings after being placed in
growing medium
69. Examples of Medicinal Roots
◼ Wafer Ash (Ptelea trifoliata) root bark is used for the digestive system. Also known as
hoptree.
74. Flowers
◼ Function
◼ Contain the sexual
organs for the plant.
◼ Produces fruit, which
protects, nourishes
and carries seeds.
◼ Attracts insects for
pollination.
75.
76.
77. Where are the reproductive structures
of plants and how do they work?
◼ Sepals- green leaf-like structures under the petals
◼ Petals- brightly colored structures on flower used to attract pollinators
◼ Stamens- male reproductive parts containing filament and anther
surrounding female parts
◼ Filament-stalk that supports anther
◼ Anther- produces pollen or male sex cells
◼ Pistils- female reproductive parts containing stigma, style, and ovary
◼ Stigma- sticky surface for capturing pollen at top of styles
◼ Style- tube-like structure that connects stigma and ovary
◼ Ovary- contains ovules or eggs
78. How do we get seeds?
◼ Pollination- occurs when pollen grains are
transferred from anther to stigma
◼ By birds, insects, bats, animals, wind
◼ Self pollination- pollen pollinates flower on same plant
◼ Cross pollination- pollen from flowers on one plant
transfer to flowers on different plant
◼ Hybrid- offspring from cross-pollinating two different
varieties of a species
◼ Fertilization- one sperm nucleus fuses with egg
cell nucleus
79. What are the types of flowers?
◼ Complete flower- has all four major parts
(sepals, petals, stamens, pistils) ex. Apple,
lily, pea
◼ Incomplete flowers- lack one or more major
parts
◼ Perfect flowers- have both stamens and pistils
◼ Imperfect flowers- lacks either stamen or
pistils, ex. Corn, squash
80. Forms of flowers
◼ Solitary flowers
◼ Inflorescence- flower clusters
◼ Cyme
◼ Spike
◼ Raceme
◼ Panicle
◼ Corymb
◼ Umbel
◼ Spadix
◼ Catkin
◼ Head
81. Parts of the Flower
◼ Sepals
◼ Outer covering of the
flower bud.
◼ Protects the stamens
and pistils when
flower is in bud
stage.
◼ Collectively known as
the calyx.
82. Parts of the Flower
◼ Petals
◼ Brightly colored
◼ Protects stamen &
pistils.
◼ Attracts pollinating
insects.
◼ Collectively called
the corolla.
83. Parts of the Flower (Stamen)
◼ Male reproductive
part
◼ Anther
◼ Produces pollen
◼ Filament
◼ Supports the anther
84. Parts of the Flower (Pistil)
◼ Female reproductive
part
◼ Ovary
◼ Enlarged portion at
base of pistil
◼ Produces ovules
which develop into
seeds
◼ Stigma
◼ Holds the pollen
grains
85. Parts of the Flower (Pistil)
◼ Style
◼ Connects the stigma with the ovary
◼ Supports the stigma so that it can be
pollinated
87. Imperfect Flower
◼ Male or female
reproductive organs
not, but not both.
◼ Example:
◼ A male flower has
sepals, petals, and
stamen, but no pistils.
◼ A female flower has
sepals, petals, and
pistils, but no stamen.
91. Flowers
◼ Imperfect flowers are always
incomplete but……..
◼ Perfect flowers are not always complete
and……..
◼ Complete flowers are always perfect.
92. Importance of Flowers
◼ Important in florist &
nursery businesses.
◼ Many plants are grown solely
for their flowers.
◼ Plants have flowers to attract insects for
pollination, but people grow them for
beauty & economic value.
◼ Also some for their medicinal values
93. Examples of Medicinal Flowers
◼ For several centuries, medical practitioners have long
acknowledged the therapeutic properties of certain flowers.
◼ More than just spanning time, this knowledge also spans
many cultures around the world.
◼ One of the greatest advantages is that flowers and plants
offer completely natural medicinal properties, often without
the scary side effects that modern pills and medications
bring on.
◼ Furthermore, remedies made from flowers can be much
cheaper than drugs marketed by pharmaceutical
companies.
94. ◼ The best places to obtain dried flowers or their
essential oils is a herbal health store or locally
referred to as traditional healers.
◼ Be careful when preparing tonics and other mixtures
since some flowers can be very potent.
◼ Pregnant or nursing mothers in particular should
consult with their doctor before using any essential
oils.
◼ To learn more about using medicinal flowers for
home remedies, have a look at some of the most
effective ones below.
95. ◼ Angelica Herb
➢ It is extremely fragrant and has a number of medicinal uses including digestive
disorders, coughs and colds.
➢ It can also be given as a strengthening tonic for seniors and children.
◼ Begonia
➢ An infusion made by soaking the flowers in hot water helps to eliminate headaches and
rid the body of toxins.
➢ The crushed flowers and leaves can also be rubbed directly on the skin to help relieve
pain and heal sores or burns.
◼ Black Cohosh
➢ Black Cohosh can be used as a stimulant of the uterus
➢ Low doses of this flower can be used to help regulate the menstrual cycles and relieve
pain.
◼ Blue Lobelia
➢ Native Indians used Blue Lobelia as a treatment for syphilis as well as less severe
ailments.
➢ Tea made with this flower helps to relieve fevers, coughs and colds, and digestive
problems.
96. ◼ Butterfly Weed
➢ Also used in Native Indian cuisine, Butterfly Weed is primarily effective in treating
respiratory and related lung issues.
➢ When ingested in large amounts, it can be used for internal cleansing and pain relief.
Direct application to the skin in the form of a poultice can help to reduce swelling or heal
wounds.
◼ Calendula
➢ The bright yellow petals of calendula flowers are most effective when mixed with other
substances to create ointments or creams.
➢ It can then be used on the skin to heal burns, cuts, and wounds.
◼ Carnation
➢ When separated from the base of the flower (which is bitter), Carnation petals can be
brewed to make an excellent tea to reduce anxiety, agitation, stress and fatigue.
➢ Moreover, it also has a healing effect on the skin and can bring down swelling.
◼ Chrysanthemum
➢ Chyrsanthemums are another flower that make a great tea when steeped in hot water.
Drinking this tea brings marked relief for those suffering from a fever, headache or
common cold.
➢ The cooled liquid can also be applied as a compress to soothe tired eyes.
97. ◼ Corn Flower
➢ These distinctive sky-blue flowers have long been used to deliver relief to medical
patients.
➢ Corn Flower tea acts as a laxative and also as a mouth cleanser.
➢ It is safe to consume the flowers in their raw state.
➢ A paste made from corn flowers brings relief to acne and tired or irritated eyes.
◼ Dandelion
➢ Dandelions are very effective for cleaning the blood and also helping with related
issues, such as anemia.
➢ In Native American culture, it was also used as a laxative and a tonic of overall
wellbeing.
◼ Foxglove
➢ Used in moderation, foxgloves have proved to be valuable in curing edema
(previously known as dropsy).
➢ It is also used as a tea to remedy coughs and colds or as a compress for skin
swellings or sores.
◼ Gardenia
◼ Gardenias feature heavily in Chinese medicine for blood cleansing and disorders,
bladder problems, and physical injuries.
◼ It also works on a mental level in helping to alleviate depression, stress, anxiety,
insomnia and similar disorders.
98. ◼ Jasmine
➢ Sweet, exotic jasmine flowers do not only make delicious cup of tea, but they also aid in
digestive issues, stomach ulcers and ulcers.
➢ Sipping this brew before bedtime can help to ward off insomnia and anxiety.
◼ Honeysuckle
➢ Honeysuckle flowers are safe to eat raw and can be used to create an antibacterial gargle
wash for sore throats.
➢ Skin rashes or inflammation are also effectively treated by applying a paste made from the
flowers.
◼ Hyssop
➢ Hyssop has been used as far back as Biblical times and is renowned for its potency against sore throats,
bronchitis, congested chests, rheumatism and arthritis.
➢ It can also be used to improve circulation of the blood.
◼ Lilac
➢ Lilacs can be steeped to make a tonic that reduces fever and to get rid of internal parasites.
➢ Skin burns or wounds are soothed and heal well when a paste or gel made from lilacs is applied.
◼ Lotus
➢ Lotus flowers are popular in both Eastern and Western cultures for their effectiveness against fever,
diarrhea and also more serious illnesses such as cholera and bronchitis.
➢ A syrup made from the flower provides much relief for bad coughs.
99. ◼ May Apple
➢ May Apples are extremely potent (even toxic) and should be used very carefully, preferably
with the supervision of a professional herbalist.
➢ A small amount can be brewed as a tea or tonic to make a powerful laxative and can also
bring on vomiting.
◼ Morning Glory (PDF)
➢ Use caution not to ingest Morning Glory seeds as it could cause strong hallucinatory
effects.
➢ The flower is used in several cultures as a laxative and general purge.
➢ Morning Glory also acts as an emmenagogue to bring on menstruation or labor.
◼ Nasturtium
➢ The anti-microbial properties of Nasturtium makes it an effective remedy against colds and
flu.
➢ It is also useful in treating infections of the lungs, bladder and reproductive organs.
◼ Passionflower
➢ Passionflower contains medical properties best suited for treating disorders such as
insomnia, agitation, anxiety, and epilepsy.
➢ It also acts on the nerves to reduce pain and induce a calming sensation.
100. ◼ Peony
➢ Medicinal use of Peonies dates back to the ancient Chinese civilization.
➢ Consuming a tonic made from the flower is helpful as a muscle relaxant in cases such
as general muscular pain and cramps and also menstrual discomfort.
◼ Peony
➢ Medicinal use of Peonies dates back to the ancient Chinese civilization.
➢ Consuming a tonic made from the flower is helpful as a muscle relaxant in cases such
as general muscular pain and cramps and also menstrual discomfort.
◼ Plum Flowers
➢ Plum flowers are primarily used in Chinese medicine to free the body from parasites
and ulcers.
➢ They are also used to boost digestive health.
◼ Rose (PDF)
➢ Roses contain a good deal of Vitamin C and are very safe for human consumption.
➢ The petals can be eaten raw to increase blood circulation, and they also relieve
depression. Rose tea acts as a mild laxative.
➢ A paste or cream made from the petals does wonders to improve the condition of the
skin, especially on the face.
◼ Purple coneflower (Echinacea purpurea) and other species of Echinacea has been used
for at least 400 years by Native Americans to treat infections and wounds, and as a general
"cure-all" (panacea). It is currently used for symptoms associated with cold and flu
101. ◼ Rosy Periwinkle
➢ Rosy periwinkle has traditionally been given as a tea for diabetes and high blood
pressure.
➢ It has also made the news in recent years for its beneficial properties towards diseases
that include leukemia, cancer and Hodgkin’s Disease.
◼ Snapdragon (PDF)
➢ Snapdragon can be used as a gentle sedative and mental relaxant.
➢ It is especially useful when battling insomnia or stress.
◼ Sunflower
➢ Consuming a brew made from sunflowers helps greatly with ulcers and menstrual
cramps.
➢ It can also be used as a wash for gargling in cases of sore throats.
102. Examples of Medicinal Flowers
◼ Wafer Ash (Ptelea trifoliata) root bark is used for the digestive system. Also known as
hoptree.
106. Fruit
Types
◼ Fruit- seed-bearing organ
◼ Fleshy fruit- composed of a soft and fleshy material with
seed or seeds enclosed
◼ Ex. Blueberry, peach, tomato, watermelon
◼ Dry fruit- consists of seed enclosed in a fruit wall that is
hard and brittle when mature
◼ Ex. Pea, oak, elm
107. Examples of Medicinal Fruits
◼ Hawthorn (specifically Crataegus monogyna and Crataegus laevigata) fruit has
been used for centuries for heart disease. Other uses include digestive
and kidney problems
108.
109.
110.
111. What are the parts of a seed?
◼ Seeds - mature, fertilizes eggs contained in the fruit
◼ Seed embryo - root, stem, & one or two seed leaves
called cotyledons
◼ Monocots - one cotyledon
◼ Dicots - two cotyledon
◼ Endosperm - contains stored food for seed
◼ Seed coat - tissue surrounding embryo and endosperm to
protect seed from moisture loss, injury
112. How do we go from seed to
plant?
◼ Germination- seed embryo goes from
dormant state to active growing state
◼ Seed absorbs water and swells
◼ Primary root develops and emerges
◼ Stem or shoot emerges
113. Medicinal seeds
◼ Celery (Apium graveolens) seed is used only occasionally in tradition medicine.
Modern usage is primarily as a diuretic.
◼ Horse chestnut (Aesculus hippocastanum) seeds, leaves, bark, and flowers have
been used medicinally for many centuries. The raw plant materials are toxic unless
processed.
◼ Water Dropwort (Oenanthe aquatica) seeds are used for coughs, intestinal gas,
and water retention.
117. Plant Structural Physiology
To understand how plants work, you need to combine knowledge of plant structure with
understanding of plant physiology.
▪This lecture topic is intended to covers some aspects of physiology, emphasizing
transport and photosynthesis.
Transport
You’ve already seen the structure of xylem and phloem and has been stated what these
plant tissues do. How does transport in these systems work? How is a redwood tree able
to move water from the soil to leaves 100m above the soil?
Successful movement is based on the chemical nature of water. Water molecules are
bonded to each other by hydrogen bonds. That makes the water in roots, xylem, and
leaves a continuous network. How does water move?
Plant Physiology
118. Transport
We’ve already seen the structure of xylem and phloem.
How does transport in these systems work?
How is a redwood tree able to move water from the soil to leaves 100m
above the soil?
Successful movement is based on the chemical nature of water as already
being alluded to.
Water molecules are bonded to each other by hydrogen bonds.
That makes the water in roots, xylem, and leaves a continuous network.
How does water move then?
119. There are 5 major forces that move water from place to place:
1. diffusion –
- The net flow of molecules from regions of higher to regions of lower
concentration.
- This is the major force moving water in gaseous (vapor) phase.
2. osmosis –
- the diffusion of liquid water molecules from a dilute solution (more
water, less solute) across a selectively permeable membrane into a
more concentrated solution (less water, more solute).
- Osmosis is important in moving water from the solution bathing cells
(the apoplast) into the cytoplasm.
- This flow will continue until the hydrostatic pressure (turgor
pressure) inside the cell balances the osmotic pressure.
120.
121. 3. capillary forces
- not only is water cohesive (tends to stick together), it is also adhesive,
sticking to hydrophilic surfaces.
- That includes carbohydrates (cellulose) of the xylem tubes’ walls.
- They are very narrow in bore sizes, and water is pulled to cover the
surface of the inside of the tubes.
- The force pulling is capillary force.
- How large can it be? It can be 1,000 atmospheres, or 15,000 lbs.
- Eventually the force of gravity balances the upward pull, in theory.
- That balance is not reached in plants, and capillary force moves water
upward to replace evaporative loss.
122. 4. Hydrostatic (Turgor) Pressure –
- Turgor pressure pushes the plasma membrane against the cell wall of
plant, bacteria, and fungi cells as well as those protist cells which have
cell walls.
- This pressure, turgidity, is caused by the osmotic flow of water from
area of low solute concentration outside of the cell into the cell's
vacuole, which has a higher solute concentration.
- Eventually, the cell's membrane is enlarged such that it pushes against
the cell's rigid wall.
- At this point the cell is said to be turgid
123. 5. Gravity –
- Gravitation, or gravity, is a natural phenomenon
by which all physical bodies attract each other.
- It is most commonly experienced as the agent that
gives weight to objects with mass and causes
them to fall to the ground when dropped.
- This could be the main force in phloem tissue
when food is being transported to various parts of
the plant
124. How much pressure is involved?
➢To move water to the top of a 33m elm tree (species doesn’t matter)
requires a pressure of 6.7 atmospheres (for those into proper SI units,
this is equivalent to 0.67 megapascals).
➢To move water to the top of a 100m redwood requires a pressure of 20
atmospheres or 2 MPa.
➢Ecologists can measure the force exerted in a plant stem using a tool
called a Schollander Bomb.
125. ➢Since the water column is continuous from the roots to the leaves,
water loss from transpiration affects the entire column.
➢Water is ‘pulled’ upward from the roots out of cohesion of water in the
entire system. How much water is transpired (and replaced by absorption
from soil into roots)? Counts to the total water movement or transported
for example,
•One corn plant may be estimated to use (transpires) about 50 – 100
gallons of water (text: 196 L)
•A tomato plant ~ 120 L
•An apple tree ~ 8000 L
•date palm (warmer, wetter, more tropical habitat) ~ 140,000 L
126. ➢Plant biologists determine how water will flow by combining these
forces into a measure called water potential.
➢Water flows from a region of high water potential to one having lower
potential.
➢There is generally a higher potential in roots and shoots than in leaves.
➢Transpiration involves water evaporating from the humid interior of
leaves and diffusing through stomata.
➢That loss generates strong forces pulling water up through the plant,
first from stems into leaves, then upward through the xylem, from roots
into xylem, and from soil into root tissues.
➢Let’s begin at the leaves and (briefly) follow the process and forces…
127. ➢Air spaces within the leaves are generally in equilibrium with the
liquid water in cellulose fibrils of cell walls, i.e. at 100% relative
humidity. Air outside the leaves is almost always at a lower relative
humidity.
➢That difference drives diffusion, as long as there is an available
pathway. Given hydrophobic cuticle, the pathway is through stomata
when they are open.
➢How fast water diffuses out is in part determined by the thickness of
the boundary layer around the leaf, a region of almost unstirred air.
Thicker boundary layers slow diffusive loss.
➢What can make for a thicker boundary layer? A dense layer of
trichomes does the job. So does putting stomatal openings below the
surface of the leaf, in stomatal crypts.
129. Loss of water from intercellular spaces within the leaf causes water to
evaporate from the surfaces of cellulose cell walls. That produces
capillary forces attracting water from adjacent areas of the leaf.
Much of that water comes from inside plant cells, moving across the
plasma membrane (osmosis). Turgor pressure decreases. Cell walls
‘relax’, and, if sufficient water is lost without replacement, the leaf wilts.
If the plant is well watered, then replacement is available from the
xylem. This water flows out of tracheids through the pits in their
secondary cell walls and into fibrous cell walls of the mesophyll cells.
What follows on the next slide is a diagrammatic representation of these
movements…
130.
131. Water flowing out of a tracheid pulls on the rest of the water in the
tracheid and on the walls of the tracheid. That force is transferred by
hydrogen bonding of water through the system.
The walls of the tracheid are strong and rigid, so the force effectively
acts only on the water column, producing a hydrostatic tension.
Water may move among neighboring tracheids under this pressure, and
may move up through the column of tracheids. However, tracheids are
connected only by pits, which makes this path high resistance. Vessels
are uninterrupted, have larger diameters, and are, therefore, a low
resistance path.
Tracheids are too small for bubbles to form, blocking flow and there are
many of them. Blocking one tracheid has little impact. Not so in vessels.
132. What causes bubbles? Very high tension and freezing mostly.
Angiosperms have xylem with both tracheids and vessel elements.
Conifers (dominant in boreal forests with cold climates) have only
tracheids. This may explain, in part, their dominance there.
Finally, there is flow into the xylem in roots. The xylem pulls water from
the intercellular space (the apoplast) of the stele (the core of the root).
The water flowing from apoplast into xylem is replaced by water
flowing into the stele from root cortex. In turn, that cortical water is
replaced by water drawn into the root from the soil.
133. The movement from cortex to stele involves both apoplast and
symplast (the interconnected cytoplasms of adjacent cells). The
pathways work in parallel as shown below:
134. There is a limit to water movement through the apoplast. There is a layer
of cells around the stele called endodermis, and these cells have
something called a Casparian strip on their walls made of suberin (and
sometimes lignin) that prevents intercellular water movement into the
stele. Water is transported to the stele at this point by the symplastic path
only.
135. Now let’s move to transport of sugars in phloem. It is commonly sucrose
(common table sugar) that is exported from leaves. Export is by means of
the sieve tubes of phloem.
The rate of movement in sieve tubes is ~ 1-2 cm/min. This is faster than
diffusion or cell-to-cell transport, but slower than the movement of water
in vessel elements of xylem.
The current belief is that the sucrose is carried along with a bulk flow of
solution. The flow is directed by a gradient in hydrostatic pressure, and is
powered by an osmotic pump.
Sucrose is the solute that is osmotically active. It is pumped from
photosynthetically active cells into sieve tubes of small, minor veins.
Accumulation of sucrose in sieve tube cells pulls water into the cells by
osmosis. That increases hydrostatic pressure at a source of sucrose. That
initiates flow.
136. Flow directs the water and sucrose to areas where sucrose is in low
concentration (a sink). At the sink, sucrose is removed from sieve tubes
(and water, as well) by companion cells. That decreases hydrostatic
pressure in the sieve tube at the sink, so that a difference in pressure is
maintained, and flow continues from the source to the sink.
The same tissue can be a sink at one time and a source at another, e.g.
• a young, growing leaf starts out as a sink; once mature its sucrose is
exported and it is a source
• carrots are biennial plants – they complete their life cycle over two
years. In year 1 the root is a sink, a storage organ for starch and sugar
in its parenchyma cells. In year 2, when the shoot starts to bolt and
flower, the root becomes a source.
137. This diagram does not incorporate the importance of companion cells in
sieve tube unloading.
138. Photosynthesis
Photosynthesis involves two sets of reactions: the light reactions and
‘dark’ reactions (that are otherwise called the Calvin cycle).
The Light Reactions
These reactions occur on the thylakoid membranes of chloroplasts. There
are two photosystems involved, named, logically enough, Photosystem I
and Photosystem II.
Each of these photosystems contains proteins complexed with
cholorophyll pigments, and photosystem II also contains carotenoids.
The chlorophyll and carotenoids are organized into light harvesting
complexes. They trap photons.
139. The energy of the trapped photon excites a chlorophyll a molecule and,
through what is called resonance, that energy is transferred to a
Photosystem reaction centre.
Either directly (if the photon excited Photoystem I) or indirectly via
electron transport (if the photon excited Photosystem II), light energy is
converted into electron energy that is used in electron transport to NADP
to reduce it to NADPH, splitting water and releasing an electron and
oxygen.
140. Showing both photosystems I and II…in addition to reducing NADP to
NADPH (photosystem I), ATP is produced when light excites
photosystem II.
Fd – ferredoxinPq – plastoquinone Pc - plastocyanin
141. The diagram on the previous slide showed the excitation of Photosystem
II caused P680 to become oxidized (lose an electron). That electron is
replaced by one from water (as part of splitting water into hydrogen and
oxygen). That electron is passed through a series of carriers, losing some
energy in each step. The labeled sequence of acceptors are Pq
(plastiquinone), a cytochrome complex and plastocyanin. That energy
is captured (partly) in the formation of an ATP molecule from ADP
(called photophosphorylation).
The electron is eventually passed to an oxidized P700 of photosystem I.
When P700 was itself excited by light, it was oxidized, and passed an
electron through a series of acceptors, with the energy used to reduce
NADP to NADPH.
This whole process is non-cyclic photophosphorylation.
142. Just to make it all more complicated, photosystem I can function
independent of photosystem II, in cyclic photophosphorylation. This
sequence of electron transfer produces ATP directly, rather than forming
NADPH.
143. The energy captured in ATP and NADPH is used to drive the chemical
reactions of the Calvin-Benson cycle.
Melvin Calvin, from the University of California, won a Nobel Prize for
the ‘discovery’ and description of the dark reactions (meaning not light
requiring) of photosynthesis.
Here’s one diagram of the process.
The molecules involved:
RuBP – ribulose biphosphate
PGA – phosphoglyceric acid
PGAL – phosphoglyceraldehyde
rubisco – ribulose biphosphate
carboxylase
144. The steps of the Calvin cycle are:
1. Fixation of CO2 by enzymatically adding a carbon to ribulose 1,5
biphosphate. The enzyme is rubisco (ribulose biphosphate
carboxylase. Rubisco is a common protein in photosynthetic plants,
representing from 1/8 to 1/4 of total leaf protein.
2. The 6-carbon molecule formed is unstable, and very rapidly splits into
two 3-carbon molecules of phosphoglyceric acid (PGA).
3. PGA is modified enzymatically (with the energy input from one
NADPH and one ATP from the light reactions) into two molecules of
glyceraldehyde phosphate (PGAL). Most of the PGAL (10 out of
every 12) is used to regenerate RuBP. That makes the series of
reactions cyclic.
145. 4. The other two PGAL are re-combined enzymatically to form a 6-
carbon sugar, fructose 1,6 biphosphate. That sugar molecule is
converted rapidly to glucose, which is, in turn, converted into sucrose
or starch.
146. The Calvin-Benson cycle is universal in photosynthetic plants. However,
as you already know, there are alternatives in carbon fixation.
In C4 photosynthesis, the initial carbon fixation step uses PEP
carboxylase to attach a carbon from CO2 to phosphoenol- pyruvate, a 3-
carbon molecule, to form a 4-carbon molecule, oxaloacetate. There are
then a cycle of reactions during which a CO2 is passed to the Calvin
cycle. Note the location of these steps within the leaf. This mode of
carbon fixation is called the Hatch-Slack pathway.
CAM carbon fixation occurs as in the Hatch-Slack pathway, fixing
carbon into 4-carbon acids. The difference is in timing and location.
CAM plants fix carbon at night in the same mesophyll cells that undergo
light reactions during day.
147. This is the C4 pathway.
Carbon fixation in the
mesophyll, but Calvin cycle
reactions in the bundle sheath.
In CAM, both light and dark
reactions occur in mesophyll,
but carbon fixation is limited to
nighttime hours.
148. Photorespiration
Some of the CO2 fixed in photosynthesis is lost to photorespiration.
The actions of rubisco depend on the relative concentrations of CO2 and
O2 in the leaf. When CO2 is high, rubisco acts to catalyze the addition of
CO2 to RuBP. However, when O2 is high and CO2 low, rubisco catalyzes
the addition of O2 to RuBP. Eventually, CO2 is formed, but without
formation of ATP or NADPH.
This occurs in C3 plants, but not in C4 plants, and, on a hot day, may cost
a C3 plant as much as 50% of fixed carbon, at a high energy cost. On
cooler days (or in cooler climates) when photorespiration is low or
unlikely to occur, C3 plants are more efficient (expend less energy) to fix
CO2.
149. Photorespiration is, therefore, a key factor in explaining the distributions
of C3 and C4 species.
Cellular Respiration
All living organisms use energy, and form ATP to use in the many
enzymatic reactions involved in molecular synthesis. The basic steps are
glycolysis and the reactions of the Krebs cycle.
Glycolysis means the splitting (lysis) of sugars. The usual steps are to
split a glucose molecule into two three-carbon glyceraldehyde phosphate,
then convert those molecules into pyruvate molecules. The net energy-
yielding result is 2 ATP and 2 NADH being formed.
150. The pyruvate is transferred into mitochondria, where the reactions of the
Krebs cycle occur. The details (which you were probably forced to learn
in high school biology) are not critical. What is important is the energy
result of the cycle of reactions.
The two molecules of pyruvate that are produced from one molecule of
glucose yield 2 ATP, 8 NADH and 2 FADH2 in being carried through the
Krebs cycle.
These energy-rich molecules are passed to the electron transport
system of the mitochondria, where more ATP is produced (24 ATP from
8 NADH). The process is called oxidative phosphorylation.
The Krebs cycle is diagrammed on the next slide.
151.
152. And here is a diagram of the electron transport chain. These proteins are
all located on the internal membrane (the crista) of the mitochondrion.
153. There are many more important components of plant physiology, some
of which may arise later in the semester (e.g. plant hormones). This has
been a “bare bones” treatment of a few basics.
155. Some Key Concepts
◼ Diffusion: movement of molecules
from high to low concentration.
◼ Osmosis: diffusion across a semi-
permeable membrane.
◼ Mass or bulk flow: movement of fluid
due to pressure or gravity differences.
156.
157.
158.
159.
160.
161.
162.
163.
164. Long-distance movement of water
◼ Plants mostly obtain water & minerals
from soil.
◼ Water moves up the xylem by bulk
flow.
◼ Movement of water depends on
transpiration pull, cohesion & adhesion
of water molecules, capillary forces, and
strong cell walls.
165.
166.
167. •transpirational pull
•flow from greater to lower
water concentration
•relies on cohesion &
adhesion of water
–cavitation breaks chain of
water molecules
Ascent of xylem sap
169. Other mechanisms of water
transport not important.
◼ Diffusion (note mosses, etc.)
◼ Capillary forces
◼ Osmotic pressure (guttation)
170.
171. The availability of soil water and minerals
Long-distance transport of water from roots to leaves
172. Mineral Uptake Key Points
◼ Mineral movement to root by diffusion or bulk flow or
root growth.
◼ Uptake controlled at root endodermis.
◼ Uptake by either simple diffusion (no protein),
facilitated diffusion (protein channel), or active uptake
(requires energy and a protein carrier).
◼ Organisms concentrate minerals and most other
substances.
◼ Usually biggest energy expenditure of roots, cause
nutrients are being concentrated.
173.
174.
175.
176.
177. Movement of sugars
◼ Sugars (etc.) move from the source
◼ Photosynthetic leaves
◼ Storage organ
◼ To the sink
◼ Growing organs
◼ Developing storage tissue
◼ Through mass flow in phloem
◼ Pressure Flow Hypothesis
178. Phloem transport
◼ pressure flow
1 high sugar concentration
at “source”
2 sugar diluted with water
from xylem creating
pressure for flow
3 sugar unloaded at “sink”
where it is metabolized
or converted to starch
4 excess water flows to
xylem back to “source”
◼ translocation:
movement of food from
“source” to “sink(s)”
Pressure flow in a sieve tube
180. Some “hot” areas in plant
water and nutrient research
◼ Improving plant water-use efficiency
◼ Improving salt tolerance
◼ Improving nutritional value of plants
(e.g., golden rice, increasing Fe
content)
◼ Phytoremediation
183. Life processes are driven by
energy
◼ Plants are dynamic metabolic systems
◼ 1000s of reactions occur every second
◼ Processes can be
◼ energy consuming (endergonic) or
◼ energy releasing (exergonic) and
◼ catabolic (breakdown) or
◼ anabolic (synthesis)
184.
185.
186.
187. The most common and
important forms of cellular
energy.
◼ Chemical bonds (e.g., ATP, CH2O)
◼ Electrons (redox reactions)
◼ Electrochemical gradients
188.
189.
190. Cellular respiration
◼ Chemical-bond energy in sugars is converted
to energy-rich compound ATP which can
then be used for other metabolic reactions
191.
192.
193.
194.
195.
196. Energy yield depends on
oxygen
◼ Aerobic (with oxygen)
◼ 36 ATP molecules per glucose molecule
◼ Anaerobic (without oxygen)
◼ 2 ATP molecules per glucose molecule
197.
198.
199. Medicinal Plants
◼ Abscess root (Polemonium reptans) is used to reduce fever, inflammation, and
cough.
◼ Açai (Euterpe oleracea) Although açai berries are a longstanding food source for
indigenous people of the Amazon, there is no evidence that they have historically
served a medicinal, as opposed to nutritional role. In spite of their recent popularity in
the United States as a dietary supplement, there is currently no evidence for their
effectiveness for any health-related purpose.
◼ Arnica (Arnica montana) is used as an anti-inflammatory and for osteoarthritis.
◼ Asafoetida (Ferula assa-foetida) might be useful for IBS, high cholesterol, and
breathing problems.
◼ Ashoka tree (Saraca indica) is used in Ayurvedic traditions to treat gynecological
disorders. The bark is also used to combat oedema or swelling.
200. ◼ Asthma-plant (Euphorbia hirta) has been used traditionally in Asia to treat
bronchitic asthma and laryngeal spasm. It is used in the Philippines for dengue
fever.
◼ Astragalus (Astragalus propinquus) has long been used in traditional Chinese
medicine to strengthen the immune system, and is used in modern China to
treat hepatitis and as an adjunctive therapy in cancer.
◼ Barberry (Berberis vulgaris) has a long history of medicinal use, dating back to
the Middle Ages particularly among Native Americans. Uses have included skin
ailments,scurvy and gastro-intestinal ailments.
◼ Belladonna (Atropa belladonna), although toxic, was used historically in Italy by
women to enlarge their pupils, as well as a sedative, among other uses. The name
itself means "beautiful woman" in Italian.
◼ Bilberry (Vaccinium myrtillus) used to treat diarrhea, scurvy, and other conditions.
◼ Bitter gourd (Momordica charantia) is used as an agent to reduce the blood
glucose level.
◼ Bilberry (Vaccinium myrtillus) used to treat diarrhea, scurvy, and other conditions.
◼ Bitter gourd (Momordica charantia) is used as an agent to reduce the blood
glucose level.
◼ Bitter leaf (Vernonia amygdalina) is used by both primates and indigenous
peoples in Africa to treat intestinal ailments such as dysentery
201. ◼ Bitter orange (Citrus × aurantium) used in traditional Chinese medicine and by indigenous
peoples of the Amazon for nausea, indigestion and constipation.
◼ Black cohosh (Actaea racemosa) historically used for arthritis and muscle pain, used more
recently for conditions related to menopause and menstruation.
◼ Blessed thistle (Cnicus benedictus) was used during the Middle Ages to treat bubonic plague.
In modern times, herbal teas made from blessed thistle are used for loss of
appetite, indigestion and other purposes.
◼ Blueberries (genus Vaccinium) are of current medical interest as an antioxidant and
for urinary tract ailments
◼ Burdock (Arctium lappa) has been used traditionally as a diuretic and to lower blood sugar
and, in traditional Chinese medicine as a treatment for sore throat and symptoms of the
common cold.
◼ Cat's claw (Uncaria tomentosa) has a long history of use in South America to prevent and
treat disease.
◼ Cayenne (Capsicum annuum) is a type of chili that has been used as both food and medicine
for thousands of years. Uses have included reducing pain and swelling,
lowering triglyceride and cholesterol levels and fighting viruses and harmful bacteria, due to
high levels of Vitamin C.
◼ Chamomille (Matricaria recutita and Anthemis nobilis) has been used over thousands of years
for a variety of conditions, including sleeplessness, anxiety, and gastrointestinal conditions such
as upset stomach, gas, and diarrhea.
202. ◼ Chasteberry (Vitex agnus-castus) used over thousands of years for menstrual problems, and
to stimulate lactation.
◼ Chili (Capsicum frutescens)'s active ingredient, capsaicine, is the basic of commercial pain-
relief ointments in Western medicine. The low incidence of heart attack in Thais may be
related to capsaicine's fibronolytic action (dissolving blood clots).
◼ Cinchona is a genus of about 38 species of trees whose bark is a source of alkaloids,
including quinine. Its use as a febrifuge was first popularized in the 17th century
byPeruvian Jesuits.
◼ Clove (Syzygium aromaticum) is used for upset stomach and as an expectorant, among other
purposes. The oil is used topically to treat toothache.
◼ Coffee senna (Cassia occidentalis) is used in a wide variety of roles in traditional medicine,
including in particular as a broad-spectrum internal and external antimicrobial, for liver
disorders, for intestinal worms and other parasites and as an immune-system stimulant.
◼ Comfrey (Symphytum officinale) has been used as a vulnerary and to
reduce inflammation. It was also used internally in the past, for stomach and other ailments,
but its toxicity has led a number of other countries, including Canada, Brazil, Australia, and
the United Kingdom, to severely restrict or ban the use of comfrey.
203. ◼ Cranberry (Vaccinium macrocarpon) used historically as a vulnerary and for urinary
disorders, diarrhea, diabetes, stomach ailments, and liver problems. Modern usage
has concentrated on urinary tract related problems.
◼ Dandelion (Taraxacum officinale) was most commonly used historically to treat liver
diseases, kidney diseases, and spleenproblems
◼ Digitalis (Digitalis lanata), or foxglove, came into use in treating cardiac disease in
late 18th century England in spite of its high toxicity. Its use has been almost entirely
replaced by the pharmaceutical derivative Digoxin, which has a shorter half-life in
the body, and whose toxicity is therefore more easily managed. Digoxin is used as
an antiarrhythmic agent and inotrope
◼ Dong quai (Angelica sinensis) has been used for thousands of years in Asia,
primarily in women's health.
◼ Elderberry (Sambucus nigra) berries and leaves have traditionally been used to
treat pain, swelling, infections, coughs, and skin conditions and, more
recently, flu, common cold, fevers, constipation, and sinus infections.
◼ Ephedra (Ephedra sinica) has been used for more than 5,000 years in traditional
Chinese medicine for respiratory ailments. Products containing ephedra for weight
loss, energy and athletic performance, particularly those also containing caffeine,
have been linked to stroke, heart arrhythmia, and even death. Such products have
been banned in the United States since December 2003. Other dietary
supplements containing ephedra were similarly banned in February 2004.
204. ◼ European mistletoe (Viscum album) has been used to treat seizures, headaches, and other
conditions.
◼ Evening primrose (Oenothera spp.) oil has been used since the 1930s for eczema, and more
recently as an anti-inflammatory
◼ Fenugreek (Trigonella foenum-graecum) has long been used to treat symptoms
of menopause, and digestive ailments. More recently, it has been used to treat diabetes, loss of
appetite and other conditions.
◼ Feverfew (Tanacetum parthenium) has been used for centuries
for fevers, headaches, stomach aches, toothaches, insect bites and other conditions.
◼ Flaxseed (Linum usitatissimum) is most commonly used as a laxative. Flaxseed oil is used for
different conditions, including arthritis
◼ Goldenseal (Hydrastis canadensis) was used traditionally by Native Americans to treat skin
diseases, ulcers, and gonorrhea. More recently, the herb has been used respiratory tract and a
number of other infections
◼ Guava (Psidium guajava) has a rich history of use in traditional medicine. It is traditionally
used to treat diarrhea; however, evidence of its effectiveness is very limited
◼ Gum Arabic (Senegalia senegal) might be useful for dental plaque and weight loss.
◼ Garlic (Allium sativum) widely used as an antibiotic and, more recently, for
treating cardiovascular disease
205. ◼ Ginger (Zingiber officinale) is used to relieve nausea
◼ Ginseng (Panax ginseng and Panax quinquefolius) has been used medicinally, in particular in
Asia, for over 2,000 years, and is widely used in modern society.
◼ .
◼ Henna (Lawsonia inermis) exhibits potential antibacterial activity. The alcoholic extract of the
root has antibacterial activity due to the presence of flavonoid and alkaloids. Henna is also
thought to show anti-inflammatory, antipyretic, and analgesic effects in experimental animals.
◼ Hibiscus (Hibiscus sabdariffa)
◼ Hoodia (Hoodia gordonii) is traditionally used by Kalahari San (Bushmen) to
reduce hunger and thirst. It is currently marketed as an appetite suppressant.
◼ Horsetail (Equisetum arvense) dates back to ancient Roman and Greek medicine, when it was
used to stop bleeding, heal ulcers and wounds, and treat tuberculosis andkidney problems.
206. ◼ Jamaica dogwood (Piscidia erythrina / Piscidia piscipula) is used in traditional medicine for
the treatment of insomnia and anxiety, despite serious safety concerns. A 2006 study
suggested medicinal potential.
◼ Kava (Piper methysticum) has been used for centuries in the South Pacific to make a
ceremonial drink with sedative and anesthetic properties. It is used as a soporific, as well as
for asthma and urinary tract infection
◼ Khat is a mild stimulant used for thousands of years in Yemen, and is banned today in many
countries. Contains the amphetamine-like substance cathinone.
◼ Konjac (Amorphophallus konjac) is a significant dietary source of glucomannan, which is
used in treating obesity, constipation, and reducing cholesterol.
◼ Kratom (Mitragyna speciosa) Kratom is known to prevent or delay withdrawal symptoms in
an opioid-dependent individual, and it is often used to mitigate cravings thereafter. It can also
be used for other medicinal purposes. Kratom has been traditionally used in regions such as
Malaysia, Thailand, and Indonesia.
◼ Kanna (Sceletium tortuosum) African treatment for depression. Suggested to be an SSRI or
have similar effects, but unknown mechanism of activity.
◼ Lavender (Lavandula angustifolia) was traditionally used as an antiseptic and for mental
health purposes. It was also used ancient Egypt in mummifying bodies. There is little scientific
evidence that lavender is effective for most mental health uses.
207. ◼ Lemon (Citrus limon), along with other citruses, has a long history of use
in Chinese and Indian traditional medicine. In contemporary use, honey and lemon is
common for treating coughs and sore throat.
◼ Licorice root (Glycyrrhiza glabra) has a long history of medicinal usage in Eastern and
Western medicine. Uses include stomach ulcers, bronchitis, and sore throat, as well
as infections caused by viruses, such as hepatitis.
◼ Lotus (Nelumbo nucifera) Sacred lotus has been the subject of a number of in-vitro and
animal studies, exploring its pharmacologic effects, including antioxidant, hepatoprotective,
immunomodulatory, anti-infective, hyperlipidemic, and psychopharmacologic activity although
clinical trials are lacking.
◼ Marigold (Calendula officinalis), or calendula, has a long history of use in treating wounds
and soothing skin
◼ Marsh-mallow (Althaea officinalis) has been used for over 2,000 years as both a food and a
medicine
◼ Moringa oleifera is used for food and traditional medicine. It is undergoing preliminary
research to investigate potential properties of its nutrients and phytochemicals
MoringaplantinGarden
◼ Milk thistle (Silybum marianum) has been used for thousands of years for a variety of
medicinal purposes, in particular liver problems.
◼ Neem (Azadirachta indica), used in India to treat worms, malaria, rheumatism and skin
infections among many other things. Its many uses have led to neem being called "the village
dispensary" in India.
◼ Noni (Morinda citrifolia) has a history of use as for joint pain and skin conditions.
208. ◼ Opium poppy (Papaver somniferum) is the plant source of morphine, used for pain relief.
Morphine made from the refined and modified sap is used for pain control in terminally ill
patients. Dried sap was used as a traditional medicine until the 19th century.
◼ Oregano (Origanum vulgare) Used as an abortifacient in folk medicine in some parts of Bolivia
and other northwestern South American countries, though no evidence of efficacy exists in
Western medicine. Hippocrates used oregano as an antiseptic, as well as a cure for stomach
and respiratory ailments. A Cretan oregano (O. dictamnus) is still used today in Greece as a
palliative for sore throat. Evidence of efficacy in this matter is lacking.
◼ Papaya (Carica papaya) is used for treating wounds.
◼ Peppermint (Mentha x piperita) oil, from a cross between water mint and spearmint, has a
history of medicinal use for a variety of conditions, including nausea, indigestion, and
symptoms of the common cold.
◼ Passion Flower (Passiflora) - Thought to have Anti-depressant properties. Unknown MOA.
Used in traditional medicine to aid with sleep or depression.
◼ Red clover (Trifolium pratense) is an ingredient in some recipes for essiac tea. Research has
found no benefit for any human health conditions.
◼ Rosemary (Rosmarinus officinalis) has been used medicinally from ancient times.
◼ Sage (Salvia officinalis), shown to improve cognitive function in patients with mild to
moderate Alzheimer's disease
209. ◼ Syrian Rue (aka Harmal) (Peganum harmala) - MAOI. Can be used as an antidepressant, but
carries significant risk. Used in traditional shamanistic rites in the amazon, and is a component
of Ayahuasca, Caapi or Yajé (which is actually usually Banisteriopsis caapi but has the same
active alkaloids).
◼ St. John's wort (Hypericum perforatum), widely used within herbalism for depression.
Evaluated for use as an antidepressant, but with ambiguous results.
◼ Saw palmetto (Serenoa repens) was used medicinally by the Seminole tribe
◼ Summer savory (Satureja hortensis) extracts show antibacterial and antifungal effects on
several species including some of the antibiotic resistant strains.
◼ Tea tree oil (Melaleuca alternifolia) has been used medicinally for centuries by Australian
aboriginal people. Modern usage is primarily as an antibacterial or antifungalagent.
◼ Thunder God Vine (Tripterygium wilfordii) is used in traditional Chinese medicine to treat
inflammation or an overactive immune system
◼ Thyme (Thymus vulgaris) is used to treat bronchitis and cough. It serves as
an antispasmotic and expectorant in this role. It has also been used in many other medicinal
roles in Asian and Ayurvedic medicine, although it has not been shown to be effective in non-
respiratory medicinal roles.
◼ Tulsi (Ocimum tenuiflorum or Holy Basil) is used for a variety of purposes in Ayurvedic
medicine.
◼ Turmeric (Curcuma longa), a spice that lends its distinctive yellow color to Indian curries, has
long been used in Ayurvedic and traditional Chinese medicine to aid digestion and liver
function, relieve arthritis pain, and regulate menstruation.
210. ◼ Umckaloabo, or South African Geranium (Pelargonium sidoides), used in treating
acute bronchitis
◼ Valerian (Valeriana officinalis) has been used since at least ancient Greece and Rome for sleep
disorders and anxiety.
◼ Velvetleaf (Cissampelos pareira) is used for a wide variety of conditions.
◼ Verbena (Verbena officinalis) is used for sore throats and respiratory tract diseases.
◼ Veronica (Veronica officinalis) is used for sinus and ear infections.
◼ Vetiver (Chrysopogon zizanioides) is used for skin care.
◼ Wahoo (Euonymus atropurpureus) is a purgative and might effect the heart.
◼ Wallflower (Erysimum cheiri) contains constituents that may affect the heart.
◼ Water Germander (Teucrium scordium) has been used for asthma, diarrhea, fever, intestinal
parasites, hemorrhoids, and wounds.
◼ Water Hemlock (Cicuta virosa) Despite being one of the most poisonous plants in the world,
it is sometimes used for pain and inflammation.
◼ Water Plantain (Alisma plantago-aquatica) is used for the urinary tract.
◼ Watercress (Nasturtium officinale) may be diuretic and antibacterial.
◼ Wheatgrass (Triticum aestivum) may contain antioxidant and anti-inflammatory compounds.
211. ◼ White willow (Salix alba) is a plant source of salicylic acid, a chemical related to aspirin,
although more likely to cause stomach upset as a side effect than aspirin itself. Used from
ancient times for the same uses as aspirin.
◼ Xanthoparmelia scabrosa is a lichen used for sexual dysfunction.
◼ Yerba Santa santa (Eriodictyon crassifolium) was used by the Chumash people to keep airways
open for proper breathing.
216. Study Questions
◼ Respond to the following questions:
➢ Give a detailed description of the anatomical structures of the plant
➢ Explain the vital roles of various parts of the plants they respectively render
to the existence plants
➢ Give detailed illustration of plant parts descriptions using the following as
examples:
✓ Leaf,
✓ Stem,
✓ Root
✓ Flower
✓ Fruit
➢ Give an illustrative explanation of what is referred to as plant structural
physiology
➢ What is involved in photosynthetic process of the plant structural physiology
➢ Give a detailed description of some key concepts during the photosynthetic
process of plants
217. Study Questions
◼ Group work discussional questions:
➢ State and explain some of the natural medicinal products that can be
obtained from various stated natural resources
➢ Give a detailed description of the anatomical structures of the plant
➢ Explain the vital roles of various parts of the plants they respectively render
to the existence plants
➢ Give detailed illustration of plant leaves descriptions as critical part of the
plant
➢ Give detailed illustration of plant stems descriptions as critical part of the
plant
➢ Give detailed illustration of plant roots descriptions as critical part of the
plant
➢ Give detailed illustration of plant flowers descriptions as critical part of the
plant
➢ Give detailed illustration of plant fruits descriptions as critical part of the
plant
➢ Give an illustrative explanation of what is referred to as plant structural
physiology
➢ What is involved in photosynthetic process of the plant structural physiology
➢ Give a detailed description of some key concepts during the photosynthetic
process of plants
