botanical nomenclature monocotyledons and … · monocotyledons and dicotyledons life cycle of...
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© Endeavour College of Natural Health endeavour.edu.au 1
Botanical Nomenclature
Monocotyledons and Dicotyledons
Life Cycle of Flowering Plants Seeds
WHMF121
Session Three
(Photograph with permission - Wendy Williams)
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Today’s Topic
Botanical Nomenclature
Understand the difference between the 2 types of
flowering plants:
Monocotyledons & Dicotyledons
The process of germination
We will start some seeds germinating in class
Seasonal variation in plants
© Endeavour College of Natural Health endeavour.edu.au 3
Botanical Nomenclature
• Phylogeny (evolutionary or ancestral
relationships between organisms) is the basis of
taxonomy (system of organising living things), in
which the species is the basic unit.
• This is essential to the understanding of
taxonomy.
• Nomenclature is defined as: “The procedure of
assigning names to the kinds and groups of
organisms listed in a taxonomic classification”.
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Botanical Nomenclature
• Taxonomy is the group of plants – this occurs
first – to what Family do they belong to?
• Nomenclature then happens – the plant is given
its name
• Common names for plants are as diverse as
the environments in which they grow. The
names can vary by region and nation
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Botanical Nomenclature
• Carl von Linné / Linnaeus (1707 – 1778) was the man who pioneered the system of classifying all living organism
• Binomial nomenclature is the system of naming plants – 2 names
• Linnaeus based his plant classification on floral characteristics
• Linneaus implemented this change in 1753 with his system, of which is still used – the L. at the end of plant names.
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Botanical Nomenclature
• Nomenclature is a Science – it is governed
by the International Code of Nomenclature
(ICN) – for fish, animals, insects, bacteria,
plants etc
• Latin is used because that was the
language used by scholars during the 18th
century when many of the species were
first identified and named. Greek is also
sometimes used…
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Botanical Nomenclature
Modern taxonomy combines a number of
techniques to classify plants:
o Traditional classification as a starting point
oComparative DNA
oComparative morphology & anatomy
oComparison of chemical compounds
Modern taxonomy has been the basis of name
changes as you will see further on
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Botanical Nomenclature
A Latin binomial by convention is written in italics and
consists of two words:
1.Generic name
o - Always has a capital letter.
o - Is the name of the genus to which the species
belongs.
2.Specific epithet
o - Does not have a capital letter
o - Is specific to, or defines the species within the
genus.
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Botanical Nomenclature• The Universality of Language – the base of which is Latin
• Within the ICN there is Botanical Nomenclature –
• Binomal is the Latin with two names aka Scientific names
• The common names vary depending on many things
• A plant will only have one Generic/Scientific name, however at times of change or transition the previous name is sometimes in brackets preceded by prev.
• How to write the plants names is always the same way, for all your future assignments or articles it will be the same Family species or Family species
• The International Code is revised every six years, the last time was in Melbourne in 2011
• Check out the resource page for the link to ICBN
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Botanical Nomenclature
How the herb ‘Chamomile' is botanically classified:
• Kingdom: Plantae
• Phylum: Magnoliophyta
• Class: Magnoliopsida
• Order: Compositae
• Family: Asteraceae
• Genus: Matricaria
• Species: recutita.
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Botanical Nomenclature
o Variations from that previously as chamomile =- aka
Matricaria chamomilla
o Every plant has this breakdown.
o Sometimes you may see written in books the Generic /
Scientific name is just an initial capitalized e.g., M. recutita
o That abbreviation would only occur after the full name has
been mentioned – one of the rules in Academic / Scientific
writing
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Botanical Nomenclature
• Specific epithets may be used in combination with
different generic names to name different species. It will
often describe the species in some way:
• “piperita” means peppery
• “vulgaris” means common
• “sativa” means “of the fields”
• “tinctora” means it was used as a dye
• “longa” describing the length of leaf, stem etc
• “alba” meaning white
• “odorata” meaning fragrance
• “nigrum” meaning black
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Botanical Nomenclature
o Where did the Latin come from? Botanical Latin is usually
Greek based.
o The early botanical writers, from Pliny the Elder (23-49AD)
through Dioscorides utilised Latin until the printing press
came into use in 1450. The monks had control of the
written documents and the Benedictines used Latin –
therefore it is the ‘lingua franca’ or scientific language.
o The first herbals were medically focussed, then they
changed into creating more botanical texts.
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Botanical Nomenclature
•Hundreds of herbs have the specific epithet “officinalis”
or “officinale”
• This is because they were official medicines included in
published official Materia Medica or Pharmacopeoia
(books that tell you how the use the herbs) at the time
Linnaeus set about to give each species on earth it’s
own specific name.
• Taraxacum officinale
• Zingiber officinale
• Rosmarinus officinalis
• Symphytum officinale
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Activities to consider…
o Refer to the reading:
o “Botanical Latin - The Poetry of Herb Names”
• Find 6 medicinal plants you know, find their Botanical
names and the meaning of their names
• Why does the spelling of the word officinalis / officinale
differ?
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Hybrid Plants• Plants of two different species do not usually interbreed
• When interbreeding does occur the offspring is said to be a hybrid.
• Hybrid species have not evolved like other species but have been bred by crossing parents of different species.
• Hybrids are named using both parents names separated by “x”
• Digitalis lutea crossed with Digitalis purpurea would be “Digitalis lutea x D.purpurea.
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Hybrid Plantso Another term for cross breed,
o These are a subspecies, that come about due to intentional plant breeding
o It occurs when the best traits of each parent plant are cross pollinated
o As you can see the written terminology also has its own format
o Peppermint is Mentha x piperita and Spearmint is Mentha xspicata
o And Pennyroyal, another member in the Mint (Mentha) family, pennyroyal is Mentha x pulegium
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Hybrid Plants
o International Code of Nomenclature for Cultivated
Plants (ICNCP), also known as the Cultivated Plant
Code, is a guide to the rules and regulations for naming
plants whose origin or selection is primarily due to
intentional human activity – namely cultivars.
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Botanical Nomenclature
• Herbalists do not use common names and always use the
herbs scientific name to avoid confusion.
• Dirr’s Manual of Woody Landscape Plants, 5th Edition.
• White Waterlily has:
• 15 common names in English
• 44 common names in French
• 81 common names in German
– but only one Latin name Nymphaea alba L.
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Botanical Nomenclature
• As a Naturopathic student, start now and always use the
herbs scientific name to avoid any confusion.
o Nomenclature is separate from Taxonomy - The body of
rules prescribing which name applies
o Botanical Nomenclature is the crossing over between
specialities –
o Horticulture + Botanist + Herbalist +
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The International Code of
Nomenclature for algae, fungi and
plants (ICN)• Most plants have a common name which varies from country to
country and regionally within countries.
• The ICN formalises the convention for the scientific or botanical naming of plants, especially the names of species.
• Formed in 1867, it regularly meets every six years to discuss changes to plant names or the naming of new species.
• According to the ICN, Latin names used in print are either italicised or underlined.
o Example: Mentha x piperita or Mentha piperita
© Endeavour College of Natural Health endeavour.edu.au 22
The International Code of
Nomenclature for algae, fungi and
plants (ICN)o The International Rules came into play in 1906
o The most recent collaboration was in Schenzhen, China in 2017, previous to that it was in Melbourne 2011 – therefore it is anticipated there may be some name changes being implemented in the near future.
o The International Code of Nomenclature for algae, fungi, and plants(ICN) is the set of rules and recommendations dealing with the formal botanical names.
o It was formerly called the International Code of Botanical Nomenclature(ICBN); according to the Melbourne Code.
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Botanical Names can Change•Classification and names can be changed for 3 reasons:
1. To be consistent with new conventions
2. More information or material becomes available
3. Information is reinterpreted or a different opinion
becomes accepted.
•More information regarding ICN:http://courses.washington.edu/bot113/summer/WebReadings/PdfReadings/BOTANICAL_NOMENCLATURE.pdf
4/7/16
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Botanical Names can Changeo Prior to the Botanical Congress, there are four days dedicated just to
Nomenclature – the changes are then taken to the Congress, where it
then gets turned into a rule.
o Digitizing of everything is doing away with the plant specimens that
have ben used for hundred of years…
o An important change was implemented in 2012, whereby New plants
no longer require a Latin name.
o New species now only need to be described and published in a
scientific journal where anyone can access the information and digital
versions are acceptable.
o The DNA determinants of the plant also need to be sent to Kew for
verification that it is indeed a new species
© Endeavour College of Natural Health endeavour.edu.au 25
These names changed at the last meeting of the ICBN in
2012 in Melbourne & validated by the Australian Register of
Therapeutic Goods as the correct medicinal plant names.
Old Name New Authenticated Name
Aloe barbadensis Aloe vera
Anthemis nobilis Chamaemelum nobile
Cassia senna Senna alexandrina
Cimicifuga foetida Actaea cimicifuga
Cimicifuga heracleifolia Actaea heracleifolia
Cimicifuga racemosa Actaea racemosa
Pulsatilla vulgaris Anemone pulsatilla
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Changes to naming of Plant
Families
o Even the plant families can be changed, as well
as plants getting reassigned to different families.
o This has come about as the DNA is being
compared and there is more details known
about each plant.
o Again the terminology sometimes is slow to
change
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Changes to naming of Plant
Families
Common name Former name Current name Typical genus
Parsely family Umbelliferae Apiaceae Apium
Daisy family Compositae Asteraceae Aster
Cabbage family Cruciferae Brassicaceae Brassica
Bean family Leguminosae Fabaceae Faba
Mint family Labiatae Lamiaceae Lamium
Grass family Graminae Poaceae Poa
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Flowering PlantsThe Division Anthophyta/Magnoliaphyta (Angiosperms) is divided into two very different classes:
• Class Monocotyledones (Liliopsida)• Have one seed leaf “mono”=one;” “cotyledon”=seed
leaf.• Often called monocots.• Approximately 62,000 species.• e.g. Grasses, Lilies, Irises, Orchids, Palms.
• Class Dicotyledones (Magnoliopsida)• Have two seed leaves “di”=two; “cotyledon”=seed leaf• Often called dicots• Approximately 290,000 species• e.g. Trees, Bushes, Herbs
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Monocots & Dicots
Plant Parts Monocotyledons Dicotyledons
Seeds 1 cotyledon 2 cotyledons
Roots Fibrous root system Tap root system
Vascular Tissue Scattered bundles Bundles in a ring
Stems Usually herbaceous Herbaceous or woody
Leaves Typically parallel
venation
Typically reticulate
venation
Flowers Parts usually in 3’s Parts usually in 4’s or
5’s
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Monocotyledon
• Monocots seeds have
only one seed leaf or
cotyledon inside the
seed coat.
•
• It is often only a thin leaf,
because the endosperm
to feed the new plant is
not inside the seed leaf.
• As it germinates it
produces 1 seed leaf -
‘mono’ meaning one (1)
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Monocotyledon
•Monocots seeds have an outer layer
- Pericarp
•Endosperm is the food/energy source
•Within the embryo are the plumule
and radicle.
• Plumule - enclosed in the coleoptile
that will grow into the stem
•Radicle - enclosed in the coleorhiza
that will grow into the root
•Many medicinal & foods are seeds -
Poaceae family [wheat, oats, corn] as
well as Sesame, sunflower, pumpkin,
celery, linseed. Nuts are also seeds
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Dicotyledons• Dicots seeds have two seed
leaves or cotyledons inside
the seed coat.
• They are usually rounded
and fat, because they contain
the endosperm to feed the
embryo plant.
• As it germinates, it produces
two seed leaves - ‘di’ means
two (2)
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Dicotyledons
• Dicots seeds
Outside coast of the seed is called
the Testa
Hilium – is the attachment scar,
where the seed was joined in the
ovary to the seed stalk in the ovary
Micropyle – is the hole where the
pollen entered
© Endeavour College of Natural Health endeavour.edu.au 34
Can you identify the monocot?
(Halasz, n.d. https://bioweb.uwlax.edu/bio203/s2013/phillips_reb2/classification.htm)
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Monocotyledons• The stems of monocots
are usually unbranched
and fleshy.
• The vascular tissue is
scattered
• They do not grow thicker
from year to year.
• New leaves often grow
wrapped in a protective
sheath formed by the
older leaf - grasses
• The roots are fibrous
(Photograph with permission - Wendy Williams)
© Endeavour College of Natural Health endeavour.edu.au 36
• The stems of dicots are
usually tough.
• They can grow wider each
year and are often
branched.
• The vascular tissue is
bundled in a ring
• The root is often a single
long tap root with smaller
feeder roots growing from
it.
Dicotyledons
(Photograph with permission - Wendy Williams)
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Can you spot the Dicotyledon?
(http://apbio-werle.wikispaces.com/Plants)
vascular bundles
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Monocotyledon
• The leaves of monocots are often long and narrow, with their veins in straight lines up and down the leaf.
• Sometimes, the veins run from the centre of the leaf to the edge, parallel to one another.
(Photographs with permission - Wendy Williams)
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• The leaves of dicots come in many different shapes and sizes.
• The veins go from the central midrib to the edge of the leaf, crossing and joining to form a netted pattern all over the leaf.
Dicotyledons
(Photographs with permission - Wendy Williams)
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Monocotyledons
o Monocot flowers are in
multiples of threes.
o Sepals are often the same
colour as the petals.
o Usually the same number
of stamens as petals.
(Photographs with permission - Wendy Williams)
© Endeavour College of Natural Health endeavour.edu.au 41
o Dicot flowers are usually in multiples of
• fours or fives.
Dicotyledons
(Photographs with permission - Wendy Williams)
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Monocots and Dicots
Fill in the Blanks
Plant Parts Monocotyledons Dicotyledons
Seeds
Roots
Vascular Tissue
Stems
Leaves
Flowers
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(https://commons.wikimedia.org/wiki/File:Monocot_vs_Dicot.svg)
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Seeds
• The gymnosperms and angiosperms together comprise
the spermatophytes or seed plants.
• The ancestors of flowering plants diverged
from gymnosperms around 245–202 million years ago,
and the first flowering plants known to exist are from 140
million years ago.
• They diversified enormously during the Lower
Cretaceous period and became widespread around 100
million years ago, but replaced conifers as the dominant
trees only around 60-100 million years ago.
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Seeds
• All plants produce an embryo after fertilisation but the
presence of food gives the embryo greater chances of
survival.
• The coat protects the embryo from unfavourable conditions
and the food source allows the embryo to wait until
environmental factors are suitable for germination.
• This allows the gymnosperms and angiosperms (the seed
plants) a greater evolutionary advantage over other plants,
as many primitive divisions produce an unprotected embryo
only.
© Endeavour College of Natural Health endeavour.edu.au 46
Seeds
• The Gymnosperms form a group of
• seed-bearing plants.
• “Gymnosperm” comes from the Greek word gymnospermos, meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilised state).
• These include: Conifers, Cycads, Ginkgo and Gnetales.
• Gymnosperm seeds develop either on the surface of scale or leaf-like appendages of cones, or at the end of short stalks (Ginkgo).
(https://commons.wikimedia.org/wiki/Plants#mediav
iewer/File:L%C3%A4rchenzapfen.jpg)
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Ginkgo biloba
male strobili
Photograph with permission – David Stelfox
female ovules
Male & female trees, the ovules
develop into nuts
(http://commons.wikimedia.org/wiki/Ginkgo_biloba#mediavi
ewer/File:Ginkgo_biloba_-_female_flower.JPG)
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Ginkgo biloba - nuts
A dissected Ginkgo seed showing the embryo
(Clark, n.d.
http://en.wikipedia.org/wiki/File:Ginkgo_emb
ryo_and_gametophyte.jpg)
(http://commons.wikimedia.org/wiki/
Ginkgo_biloba#mediaviewer/File:Gin
kgo_biloba_007.jpg)
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Seeds
• The flowering plants (angiosperms, also known
as angiospermae) are the most diverse group of land
plants.
• They can be distinguished from the gymnosperms by
a series of derived characteristics:
• Seeds or ovules are enclosed during pollination.
• Flowers
• Endosperm within the seeds
• Production of fruits that contain the seeds.
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Life Cycle of a Flowering Plant• The cycle of a flowering plant starts with:
• Fertilisation of the flower
• Fruit develops
• Seeds are produced
• Germination occurs
• Plant starts to develop
• Flowering takes place
• The cycle begins over again
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Botany – the big picture
The Story of Flowers - a botanical animation
Enjoy -
https://www.youtube.com/watch?v=vDpFyHmt0
AE
Directed by : Azuma Makoto
Illustration by : Katie Scott
Animation by : James Paulley
Visual Supervisor : Shunsuke Shiinoki
Project Management by : Eri Narita
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Terminology for Seeds• Testa - seed coat or pericarp - protects the seed
• Embryo - immature plant inside the seed
• Hilum - scar of attachment where the seed stalk joined inside the
ovary
• Micropyle - where the pollen tube entered to fertilise ovule.
• Plumule - immature shoot
• Coleoptile - encloses the plumule
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Terminology for Seeds
• Radicle - immature root
• Coleorhiza - encloses the radicle
• Hypocotyle - embryonic stem - between the radicle & plumule
• Endosperm - a source of nourishment for germinating seed
• Cotyledon - seed leaves
See The Glossary in readings
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Monocot Seed
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A picture demonstrating the testa, micropyle, hilum and the point
from which the radicle emerges inferior of the hilum.
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(https://au.pinterest.com/pin/523402787919613988/)
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Germination• Germination is the transition state between quiescent
embryo (dormancy) and a new photo-synthetically active plant. (Gimeno-Gilles et al., 2009)
• The most common example of germination is the sprouting of a seedling from a seed.
• Growth of hyphae (feeding part of fungus) from fungal spores, is also germination.
• Generally speaking, germination can imply anything expanding into something greater from a small existence or germ.
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Radicle and Plumule
(https://commons.wikimedia.org/wiki/File:Bean_germination.jpg)
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Germination
• The seed of a plant is a small package produced in
a fruit or cone after the union of male and female sex cells.
• All fully developed seeds contain an embryo and, in most
plant species some store food reserves, wrapped in a seed
coat.
• Most plants produce some seeds that do not contain
embryos, these are called empty seeds and never germinate.
• You can check for this by placing dicot seeds in water – those
that float to the top are empty.
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Germination
• Most seeds go through a period of dormancy -
quiescence.
• Dormant seeds are ripe seeds that do not germinate
because they are influenced by environmental conditions
that prevent the initiation of metabolic processes and cell
growth.
• Once the seed has favourable conditions it begins to
germinate and the embryonic tissues resume growth,
developing towards a seedling.
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Germination
• Plants need different circumstances for successful seed
germination.
• Depends on the individual seed variety and is closely
linked to the plant's natural habitat.
• Plants which grow in cold climates produce seeds that
need cold storage before germination.
• The cold temperature ensures germination will not occur
until ideal survival conditions are met e.g. bulbs.
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2 Types of Seed Germination
Hypogeous or Hypogeal
• The cotyledons remain in the ground during
germination e.g peas
• Watch time-lapse video of germination filmed over 1 week:
• https://www.youtube.com/watch?v=T-Z53GVinpk• Permission given from Neil Bromhall
http://www.mastergardenerssandieg
o.org/newsletter/article.php?ID=26
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2 Types of Seed Germination
Epigeous or Epigeal
• The cotyledons elevate above ground during germination
before they fall away e.g. beans
• Watch time-lapse video of dicot germinating:
• https://www.youtube.com/watch?v=G2RuVxdr0mA• Permission given from Neil Bromhall
https://gardenerdy.com/bean-plant-facts
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Germination
• The resumed growth (germination) of
the embryo depends on the right
combination of:
• Water
• Oxygen
• Warmth
• Particular triggers such as
light or darkness
• Hormone control
(https://commons.wikimedia.org/wiki/File:Date_Seed_sprouting-002.jpg)
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Germination - Water
• Water is required for germination as mature seeds are often extremely dry.
• Absorption of water activates enzymes in the seed that stimulate cellular metabolism. Deactivate enzyme inhibitors.
• The uptake of water by seeds leads to the swelling and the breaking of the seed coat.
• Most seeds store a food reserve such as starch, proteins, or oils.
• This food reserve provides nourishment to the growing embryo.
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Germination - Water
• After the seedling emerges from the seed coat and
starts growing roots and leaves, the seedling's food
reserves become exhausted.
• At this point photosynthesis provides the energy
needed for continued growth.
• The seedling now requires a continuous supply of
water, nutrients, and light for it’s continued
development.
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Germination - Oxygen
• Oxygen is needed by the germinating seed for
metabolism.
• Oxygen is used in cellular respiration, the main source
of the seedling's energy until it grows leaves.
• Oxygen is found in soil pore spaces.
• If a seed is buried too deeply within the soil or the soil
is waterlogged, the seed can be oxygen starved.
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Germination - Temperature
• Temperature affects cellular metabolic and growth rates.
• Seeds from different species and even seeds from the same plant germinate over a wide range of temperatures.
• Seeds often have a temperature range within which they will germinate, and they will not do so above or below this range.
• Some seeds germinate when the soil is cool (-2 - 4 C), and some when the soil is warm (24-32 C).
• Some seeds require exposure to cold temperatures to break dormancy.
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Germination - Temperature• Seeds in a dormant state will not germinate even if
conditions are favourable.
• Seeds that are dependent on temperature to end
dormancy have a type of physiological dormancy.
• For example:
• Seeds requiring the cold of winter are inhibited from
germinating until the ground temperature starts to
heat up and they take in water in spring / summer.
• Some seeds will only germinate after hot
temperatures during a forest fire which cracks their
seed coats (Banksia spp.)
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Germination - After fire
Banksia telmatiaea
(http://en.wikipedia.org/wiki/File:B_telmatiaea_25_gnangarra.jpg)
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Germination - Light
• Most seeds are not affected by light or darkness.
• Some species found in forest / jungle settings, will not
germinate until an opening in the canopy allows sufficient
light for growth of the seedling.
(https://commons.wikimedia.org/wiki/File:Jungle_stream_(La_Selva_Biological_Station).jpg)
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Germination - Animal assisted
• Some seeds need
to be passed
through an
animal's digestive
tract to weaken the
seed coat enough
to allow the
seedling to
emerge.
Mistletoe
(https://commons.wikimedia.org/wiki/Mistletoe#mediaviewer/File:200501_Gui_I.JPG)
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• The bird’s stomach
acid helps soften
the seed coat &
faeces cement the
seed to the tree
branch and provide
moisture for the
germinating seed.
Viscum album
(https://commons.wikimedia.org/wiki/Mistletoe#mediaviewer/File:Viscum-album-germination.JPG)
Germinating seeds on the branch of a tree after they have
been through the digestive tract of a bird.
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Germination - Hormones
Factors affecting seed dormancy include the presence of
the plant hormones:
• Abscisic acid
– Inhibits germination
– Stops seeds from spontaneously germinating
• Gibberellin
– Ends seed dormancy
– Biosynthesis precursors
– Gardeners often soaking seeds overnight before planting to
speed up germination
– Helps fruit ripen and mature
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Monocot Germination
• In monocot seeds, the radicle and plumule are
covered by a coleorhiza and coleoptile, respectively.
• The coleorhiza is the first part to grow out of the seed,
followed by the radicle.
• The coleoptile is then pushed up through the ground
until it reaches the surface.
• There, it stops elongating and the first leaves emerge.
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Dicot Germination• The part of the plant that first emerges from the seed is the
embryonic root, the radicle or primary root.
• It allows the seedling to become anchored in the ground and
start absorbing water. After the root absorbs water, an
embryonic shoot emerges from the seed.
• This shoot comprises three main parts:
• The cotyledons (seed leaves)
• The section of shoot below the cotyledons (hypocotyl)
• The section of shoot above the cotyledons (epicotyl)
• The way the shoot emerges differs among plant groups.
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3 Phases of Germination
• 1st Phase: characterized by a passive increase in water
content of the dry and mature seed.
• 2nd Phase: the water content remains constant and the
synthesis of new mRNAs and proteins start developing.
• 3rd Phase: the embryo axis elongates and radicle
emerges. A further increase in water uptake occurs
afterwards during post-germination growth and seedling
establishment.
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Rice seed germinating, notice the time frame of the 3
different phases
(http://journal.frontiersin.org/Journal/10.3389/fpls.2013.00246/full)
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Millenium Seed Bank
• Watch video – Jonathon Drori:
http://www.ted.com/talks/jonathan_drori_
why_we_re_storing_billions_of_seeds
What do you know of local Seed Saving Efforts?
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Seasonal Variation in Plants
• The earth tilts on its axis at 23.50 as it rotates around the
sun
• One revolution of the sun takes a year
• Depending on the tilt of the planet as is circles the sun,
we can have 4 seasons on planet earth:
o Temperate regions on earth have 4 seasons
o The North Pole and the South Pole only have 2
seasons, summer and winter
o The equator only has one season, summer
© Endeavour College of Natural Health endeavour.edu.au 81
(https://commons.wikimedia.org/wiki/Category:Seasons_on_Earth#media
viewer/File:Earth-lighting-equinox_EN.png)
Earths Axis – Seasonal Tilt
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(https://commons.wikimedia.org/wiki/Category:Seasons_on_Earth#media
viewer/File:Earth-lighting-equinox_EN.png)
Applying the 23.50Tilt
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• Winter
• Daylight hours greatly
reduced
• Ground temperature cools
down
• Signalling no growth period
in the plant
• Deciduous trees are
dormant
• Non-deciduous trees shed
some leaves to reduce their
photosynthetic ability eg.
Gum trees
Seasonal Variation in Plants
(https://commons.wikimedia.org/wiki/Category:Trees
_in_winter#mediaviewer/File:Bare_Tree_Sunset.jpg)
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Seasonal Variation in Plants
Spring
• Daylight hours start to increase
• Ground temperature begins to
warm up
• Signalling end of the dormancy
• Plants start switching on their
growth hormones
• New growth
• Leaves start to shoot on
deciduous trees
• Underground bulbs start to swell
and shoot
• Flower buds start developing (https://commons.wikimedia.org/wiki/Spring#mediav
iewer/File:Prunus_dulcis_LC0009.jpg)
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Seasonal Variation in Plants
• Summer
• Period of real expansion - long daylight hours
• Flowers open to release scents which can attract
pollinators
• Fruit developing
(Photographs with permission – Wendy Williams)
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Seasonal Variation in Plants
Autumn
• Daylight hours start to
reduce
• Ground temperature starts
to cool down
• Signalling plant hormones
• Sugars will be pulled out of the
leaves to the roots
• This accounts for the change
in leaf colour of some species
as chlorophyll is replaced by
carotenoids - yellow & orange
pigments
(Photo permission of Wendy Williams)
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Climate Change & Plants
Effects on Plant Diversity - Please consider…
• Species becoming extinct as they are unable to change
distribution fast enough.
• Species with long life cycles and/or slow dispersal are
particularly vulnerable.
• Isolated species are particularly vulnerable - arctic & alpine
species
• Coastal species which will be 'squeezed' between human
settlements and rising sea levels.
(http://www.bgci.org/climate/climate_change_effects/)
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Climate Change & Plants
• Coastal species which will be 'squeezed' between
human settlements and rising sea levels.
• Plant genetics may change in response to climate
change - natural selection
• Increased invasions as conditions become more
suitable for exotic species as native species become
less well suited
• Many plant communities act as 'sinks' (store carbon),
which helps to offset carbon emissions.
http://www.bgci.org/climate/climate_change_effects/)
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Foraging
• Please watch the video as it may help
you choose your plants for your
projects:
• http://www.eatthatweed.com
From the Weed Foragers Website -
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Tutorial / Practical Session
• We are going to start some seeds germinating in damp
cotton wool in disposable cups:
Monocots & Dicots
– The seeds may have been soaking over night, why?
– Which type of seed will start to photosynthesise first,
the monocot or dicot and why?
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Avocado Seed Diagram
• How many plumules will an avocado
produce & why?
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Botany - Labelling
• Label the diagram on the next slide accordingly:
• Cotyledons, embryo, testa, plumule and radicle
• Indicate where you would expect to find coleoptile and coleorhiza
• Which seed is the monocot and which is the dicot?
• What are the differences between angiosperms & gymnosperms?
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Label the Diagrams
(https://commons.wikimedia.org/wiki/File%3AMonocot_dicot_seed.svg)
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Botany Next Week
• Preparation:
– Read through the slides for session 5 – Roots
– Read through the chapter on roots in your
textbook
– Read the 2 readings attached for the session
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Suggested ReadingsChase, M.W. (2004). Monocot relationships: An overview. American Journal of
Botany 91(10): 1645–1655. doi:10.3732/ajb.91.10.1645.
Read pp. 1645-1646 and pay particular attention to the structural differences between the monocots and dicots.
Clarke, I., & Lee, H. (1987). Name that flower: The identification of flowering plants. (p. 36). Carlton, Vic: Melbourne University Press.
Dicots (pp.117, 172-4, 189, 769-80)
Mauseth, J. (2014). Botany: An introduction to plant biology (5th ed.). (pp. 440-459). MASS: Jones & Bartlett Publishers.
Tan, E. (2013). Botany of the flowering plants (4th ed.). (pp. 18-19). Preston, Vic: Northern Melbourne Institute of TAFE.
These readings will be elaborated on in the tutorial session and prior reading is essential to participate.
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ReferencesClarke, I. & Lee, H. (1987). Name that flower: The identification of flowering plants.
Victoria, Australia: Brown Prior Anderson for Melbourne University Press.
Gimeno-Gilles, C., et al. (2009). ABA-Mediated inhibition of germination is related to
the inhibition of genes encoding cell-wall biosynthetic and architecture:
Modifying enzymes and structural proteins in Medicago truncatula embryo
axis. Molecular Plant, 2(1), 108-119. Retrieved
from http://dx.doi.org/10.1093/mp/ssn092
He, D., & Yang, P. (2013). Proteomics of rice seed germination. Front. Plant Sci. 09
July 2013. Retrieved from https://doi.org/10.3389/fpls.2013.00246
Tan, E. (2004). Herbal preparations laboratory manual. Preston, VIC: Northern
Melbourne Institute of TAFE.
Tan, E. (2013). Botany of the flowering plants (4th ed.). Preston, VIC: Northern
Melbourne Institute of TAFE.
Wohlmuth, H. (1992). An Introduction to botany and plant identification (2nd ed.).
Lismore, NSW: MacPlatypus Productions.
© Endeavour College of Natural Health endeavour.edu.au 97
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