Bentham & Hooker's Classification. along with the merits and demerits of the ...
Basic_Botany_and_Plant_ Pathology_(script).ppt
1. Basic Botany and Plant
Physiology
Written By Latif Lighari, Ph.D
Cooperative Extension Program
Tennessee State University
Modified for Master Gardener training
& Presented by
Karla Kean, UT/Montgomery County Extension Agent
2. What is Botany?
Botany is the study of
plants.
An understanding of basic
botany, plant physiology and
the environmental factors
that affect plant growth can
help one gain practical
knowledge of horticulture.
4. INTRODUCTION
All flowering plants have certain structure and
functions in common.
There are also common responses to environmental
conditions.
This unit looks at what most plants have in
common, some differences between plants, and
applies this information to practical gardening.
5. INTRODUCTION
Non-vascular Plants vs. Vascular Plants
Primitive, non-vascular plants, such as liverworts
and mosses lack conductive tissue for the circulation
of water and nutrients, and are thus confined to a
moist environment.
Their small size and relatively dull appearance
render them of limited value in the landscape.
Vascular plants, which include both flowering and
non-flowering plants, are very diverse.
The adaptability of their root and shoot systems
have enabled them to establish and thrive in
many habitats.
6. PLANT PARTS AND FUNCTIONS
Stems
Leaves
Buds
Roots
Flowers
Fruit
Seeds
8. PRINCIPLE PARTS
OF A VASCULAR PLANT
Think of these parts as divided into two
groups: reproductive and vegetative.
Reproductive parts include flower buds,
flowers, fruit and seed.
Vegetative parts include roots, stems,
leaves and leaf buds.
Many vegetative parts are used in asexual or
vegetative reproduction such as cuttings,
grafting, layering, etc.
9. STEMS
Support buds, flowers
and leaves.
Transport water, minerals
and sugars through the
plant.
The points where leaves
develop along the stem
are called nodes.
Area between the two
nodes is called an
internode.
10. STEMS
The length of an internode depends on
many factors:
Vigorous growing, healthy plants
tend to have longer internodes than
less vigorous plants.
Reduced light intensity in areas of
high foliage density may increase
internode length.
11. STEMS
So, what does this mean to the gardener?
Many plants root more easily at the nodes
and some root only at the nodes.
Short, stocky transplants are more likely to
develop when plants grow in strong light,
have adequate spacing, and are only
moderately fertilized.
12. TYPES OF STEMS
A Shoot is a young stem with leaves present.
A Twig is a stem which is less that one year old and has no
leaves, since it is in the winter dormant stage.
A Branch is a stem which is more than one year old, and
typically has lateral stems.
A Trunk is a main stem of a woody plant. Trees typically
have a single trunk, but shrubs often have multiple trunks.
Vines produce long trailing stems that are sometimes able
to support themselves by winding around or attaching to
another plant or structure.
Canes are stems that usually live only a year or two.
Plants with canes include rose, grape, blackberry and
raspberry.
13. INTERNAL STEM STRUCTURE
Stems generally consist of several different
types of tissue:
Xylem: conducts water, nutrients, and
minerals from the roots to upper areas of a
plant and generally forms the wood of
woody plants.
Phloem: comprises much of the bark of
woody plants and conducts sugars from
leaves to growing points, fruits and storage
areas.
14. INTERNAL STEM STRUCTURE
Cambium: is a meristem tissue; a site of
cell division and active growth. It is located
between the xylem & phloem and is
responsible for diameter growth. The
apical meristem is responsible for stem
elongation.
Because xylem & phloem conduct water,
nutrients, and manufactured substances
throughout the plant, they are called
vascular tissues.
15. INTERNAL STEM STRUCTURE
There are two distinct
arrangements of vascular
tissue: Dicots and
Monocots.
Dicots:
Have vascular tissue
arranged in rings as
found in most trees
Monocots:
Have veins arranged in
bundles
Corn is a typical monocot
as are grasses, orchids,
lilies and palms.
16. INTERNAL STEM STRUCTURE
Most, if not all monocots lack cambium tissue
between xylem & phloem tissues. This
means that a mature monocot stem does not
increase much in diameter.
Dicots continue to increase in diameter
throughout their lives.
17. INTERNAL STEM STRUCTURE
With this knowledge of stem structure, one
can understand how a rodent chewing the
bark off a tree kills the tree.
This information is also essential in grafting.
Since only the cambium layer produces new
xylem and phloem, the cambium layer of both
plants must be exactly aligned if a graft is to
grow.
20. STEM LIFE SPAN
Plants are sometimes classified by how long
they live.
Annuals: produce seed, and die within a
single growing season. (cantaloupe, corn,
marigold etc.)
Biennials: produce vegetative structure
and food storage organs the first growing
season. The second season they flower,
fruit, develop seed and then die. (carrots,
cabbage, hollyhocks etc.)
21. STEM LIFE SPAN
Perennials: live three or more years.
Woody Perennials: have shoots & roots
which survive many years, such as many
trees & shrubs.
Herbaceous Perennials: have shoots
which die back to the ground each year
like hardy hibiscus, lilies, and many
wildflowers.
22. LEAVES
Leaves are the primary organs to
manufacture food for plants (like a
factory).
Leaves can be narrow-leaves like pine
needles or broad-leaves, like all other
plants
The enormous diversity of leaf shapes,
sizes, forms and arrangements is the result
of plants adapting to conditions in a vast
range of habitats.
24. LEAVES
The principle function of a leaf is to
manufacture plant sugars in a process called
photosynthesis (which we will discuss a bit
later). An important component of
photosynthesis is light.
Typically, flattened leaf blades present a large
area for efficient absorption of light. The vein
system conducts water, sugars & other items
through the leaf.
25. LEAVES
The greatest division within leaf types lies
between deciduous and evergreen foliage in
trees and shrubs.
Evergreen leaves are shed and replaced
throughout the year.
Deciduous leaves are all replaced annually,
mostly falling in autumn to minimize
moisture loss in winter.
26. LEAVES
The leaf blade
is comprised of
several layers
as illustrated.
The primary
function of the
epidermis is to
protect the
inner tissues.
27. LEAF SHAPE & VEIN ARRANGMENT
The term venation refers to the vein pattern
in the leaf blade.
28. LEAF SHAPE & VEIN ARRANGMENT
Leaves may be simple or compound in
arrangement:
Simple leaves consist of a single blade
Compound leaves have more than one
blade.
Compound leaves may be palmately
compound like horse chestnut, pinnately
compound like a locust, or even double
pinnately compound like the Kentucky
Coffee Tree.
30. LEAF ARRANGMENT
Leaf arrangement is another characteristic which
helps identify plants.
Opposite leaves are positioned exactly across the
stem from each other, with two leaves at each node.
Maple, ash, dogwood
Alternate leaves are arranged in steps or spiraled
along the stem.
Oak, willow, sycamore
Whorled leaves are found in circles around the stem
with 3 or more at a node.
Catalpa
32. BUDS
Buds grow at nodes and tips of the stem
A bud is a condensed form of shoot which
leaves or flower parts develop.
There are two types of buds:
Terminal Bud
Axillary or Lateral Bud
35. BUDS
Axillary buds may grow into lateral branches,
so when pruning it is important to make
pruning cuts just above an axillary bud.
It is also important that the axillary bud
just below a pruning cut point in the
direction you want the plant to grow,
whenever possible.
This bud will be the strongest new growing
point and will grow in the direction it
points.
37. BUDS
The terminal bud of many plants
produces a chemical called auxin
which inhibits the growth of nearby
lateral or axillary buds.
This is referred to as apical
dominance. If the terminal bud is
removed, several lateral buds may
quickly begin to grow.
The strongest growing bud is
frequently the one nearest the end
of the pruned stem.
Keep this in mind when pruning….
38. ROOTS
Absorb moisture and nutrients for the entire plant,
but their functions go beyond this:
Transport moisture and nutrients to the base of
the stem.
Anchor the plant, provide it with physical support
and serve as food storage organs.
In some plants, roots may be used for
propagation and as food
40. FLOWER
Flowers are usually the showiest part of the
plant and their function is sexual
reproduction.
The bright color & fragrance attracts
pollinators, usually insects, as well as
gardeners.
Since the scientific name of plants is based on
flower structure, knowledge of flowers is
essential to plant identification.
41. PARTS OF A FLOWER
Sepals (Calyx)
Petals (Corolla)
Stamen –Anther &
Filament (male
part)
Pistil –
Stigma,style and
ovary (female
part)
42. TYPES OF FLOWERS
A flower having all four parts, sepals,
petals, pistil & stamens is called a
complete flower.
If one or more of these parts is missing,
the flower is designated incomplete.
Flowers containing functional stamens &
pistils are called perfect flowers such as
peaches or tomatoes. If either of these
parts are lacking, the flower is imperfect.
43. FLOWERING PATTERNS
Peaches & tomatoes are examples of perfect
flowers.
Insects, wind or contact transfers pollen
from the anthers to the stigma which
pollinates the flower.
The pollen grows, fertilization occurs and
seed develops. These plants are self
pollinated.
44. FLOWERING PATTERNS
Other plants, such as apples & pears, require
pollen from a genetically different plant for
fertilization to occur even if they have perfect
flowers.
They must be cross-pollinated, usually by
wind or insects.
45. FLOWERING PATTERNS
Monoecious plants have flowers with male
parts (staminate) and female parts (pistillate)
located separately on the same plant.
Corn, nut trees, vine crops such as
cucumber, squash etc.
Dioecious plants are those which produce
only male or only female flowers.
Holly, ginkgo, honey locust
48. FRUITS
Fruit consists of fertilized and mature ovules
called seeds and the ovary wall.
Botanically, tomatoes are a fruit as are
squash, cucumber, eggplant and beans.
The ovary wall may be fleshy as in peach or
dry and hard as maple fruit and walnuts.
49. FRUITS
The edible portion of cantaloupe and other
fleshy fruit is not affected by the pollen
source.
The pollen source is only significant when
the seed is saved or eaten.
Corn is an example.
Cantaloupe does not taste like cucumbers
because of cross pollination.
50. TYPES OF FRUITS:
Fruits can be classified as:
Simple Fruit: develop from a single ovary,
such as cherries, peaches, apples,
tomatoes, nuts, maple seed and poppies.
Compound or Aggregate Fruits: develop
from single flowers with many ovaries;
most berries are aggregate fruits.
51. TYPES OF FRUITS:
Multiple Fruits: are derived from a tight
cluster of independent flowers borne on a
single structure.
Examples include pineapple, fig and beet
seed which are really small, dry, many-
seeded fruit.
52. SEEDS
Seed is a reproductive part
of the plant.
Seeds generally have three
main parts:
The embryo is a partially
developed plant in a
dormant stage.
The endosperm – a food
supply (Starch).
A hard seed coat
53. SEED GROWTH
Germination
Germination is the beginning of seed growth.
For germination to occur, the proper
environmental conditions must exist.
There must be:
Moisture
Oxygen
Favorable temperature and,
sometimes, light.
54. SEED GROWTH
Seeds may not germinate immediately after
ripening and remain dormant for a time.
Some seeds are dormant because of a hard
seed coat and need to be soaked in water,
nicked with a file or may require cold
treatment (stratification) for several weeks.
55. SEED GROWTH
Seeds cannot germinate unless they are living
and they live longer when maintained cool &
dry.
Reseal left-over seed packets, store in
air-tight containers in a refrigerator or
freezer.
Seed stored properly can live several
years.
56. PLANT GROWTH & DEVELOPMENT
Photosynthesis
One major difference between plants &
animals is that most plants can
manufacture their own food (sugars) while
animals cannot.
To manufacture sugars, a plant requires
energy from light, carbon dioxide from the
air, water and a suitable temperature.
57. PHOTOSYTHESIS
Photosynthesis literally means “to put
together with light.”
Carbon dioxide + water in the presence of
light = simple sugars are formed & oxygen
is given off.
Plants store energy from light first as
simple sugars, then those may be
converted to other sugars & starches &
transported to storages areas.
59. PLANT GROWTH & DEVELOPMENT
Any green plant is capable of photosynthesis;
however, the leaves are the site of most sugar
production because of their great surface area
and specialized structures.
When photosynthesis stops, plants eventually
stop growing. If it stops long enough, the
plant will die.
Any factors required for photosynthesis
(carbon dioxide, water, light, temperature)
can limit this process.
60. PLANT GROWTH & DEVELOPMENT
The importance of photosynthesis cannot be
over emphasized.
All plant life relies directly or indirectly on
photosynthesis.
All animal life feeds directly or indirectly on
plants.
Respiration: the process by which sugars &
starches are converted into energy.
61. PLANT GROWTH & DEVELOPMENT
PHOTOSYNTHESIS:
Produces sugars
Stores energy
Releases oxygen
Uses water
Uses carbon dioxide
Occurs in sunlight
Occurs in
chloroplasts
RESPIRATION
Uses sugars for
energy
Releases energy
Uses oxygen
Produces water
Produces carbon
dioxide
Occurs in darkness &
light
Occurs in all cells
62. PLANT GROWTH & DEVELOPMENT
Transpiration
Transpiration is the process by which a plant
loses water vapor, primarily through leaf
stomates.
Transpiration is part of a complex system of
water movement through plants.
The amount of water lost depends on many
environmental factors including temperature,
humidity, wind, leaf thickness and shape,
cuticle thickness, light intensity and plant
turgor.
63. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Temperature
Is the main environmental factor affecting
plant growth.
Determines planting dates, growing season
and what plants can be grown in a locale.
Contributes to rate of plant growth and
plant quality.
64. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Hardiness
Plant hardiness refers to whether a plant or
plant part will survive outdoors in a given
location.
The chief determinant of hardiness is the
degree of similarity between conditions in the
garden and those in the plant’s natural
habitat, especially soil type, fertility, drainage,
soil and air temperature, and levels of
humidity, light and rainfall.
65. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Germination
Seeds won’t grow until temperatures are
within a specific range.
Figure 15 in your text illustrates the
variation in optimum temperature and
speed of germination for some common
vegetables.
66. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Cool-Season vs. Warm Season Plants:
Cool-season plants require cool temperature to
germinate, grow and mature properly.
They can usually withstand a considerable
frost. (pansies, daffodils, peas, spinach,
lettuce)
Warm-season plants require warm temperatures
to germinate, grow and mature properly.
They are deep rooted & resistant to drought.
Frost will kill or damage most warm-season
crops. (zinnia, tomato, pepper, okra)
67. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Growth & Fruit Set
Temperature is one of the factors that affects
photosynthesis
Extremes in temperature reduce photosynthesis
and thus growth rate.
Extremes in temperature can also cause bud,
blossom or fruit drop in many crops such as
tomatoes or peppers.
This is why some plants become unproductive
during summer months.
68. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Light
Light has 3 principle characteristics that affect
plant growth: quantity, quality and duration.
Quantity: Light quantity refers to the intensity
or brightness.
Some plants require relatively low light
intensity. These plants must be placed in
low light levels such as in shaded areas.
Most plants grow best in full sunlight.
Young plants may grow tall & leggy if the
light is not bright enough for long enough.
69. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Red & Blue light are the most effective for plant
growth.
Green light is reflected by plants & is the least
effective.
Incandescent light is generally high in red &
orange light by produces too much heat to be
effective as a lighting source for plants.
Cool white fluorescent lights are high in blue &
encourage leafy growth.
70. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Duration
Light duration or photoperiod refers to the
amount of time a plant is exposed to light.
It was once thought that the length of the
light period triggered flowering in many
plants. We now know that it is the length
of uninterrupted dark period that is
important.
71. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Water
Rainfall is the primary source of water for
plants grown outdoors, and is vital for plant
growth.
Water is a primary component for:
photosynthesis
maintains turgor pressure
transports nutrients throughout the
plant.
72. ENVIRONMENTAL FACTORS
AFFECTING PLANT GROWTH
Acquisition of water: Plants acquire most of their
water from the soil through root hairs. Seedlings
will quickly be killed by a lack of water.
Larger plants suffering from lack of water will
wilt, cease growing, yellow & drop leaves,
become stunted and finally die.
Loss of water: Plants lose water through all their
parts, but most water is lost through the leaves.
This is because water loss is proportional to the
surface area exposed to air.
Plants reduce water loss by closing the
stomates.
73. PLANT CLASSIFICATION &
NOMENCLATURE
Botanical names are preferred to common names as
they are recognized internationally and apply to only
one plant.
Example:
Family: Rosacea
Genus: Rosa
Species: Rosa eglanteria
Subspecies: Rosa subsp. gallica
Varieties: Rosa gallica var. officinalis
Cultivars: Rosa “Cordon Bleu”
74. CONCLUSION
Every plant is hardy in its natural, native
habitat, since it has survived by adapting to
the distinctive conditions that exist there.
Flowering plants have evolved a range of
strategies and structures that enable them to
survive and reproduce in diverse habitats.
Knowing how plants function and
understanding their life cycle are vital to
raising and maintaining healthy specimens.
