R2101: Plant classification, structure and function Flashcards
Exam syllabus notes for personal revision for RHS Level 2 exams. All information in answers is my own gathered by independent research across multiple resources and media. Feel free to study however I take no responsibility for any inaccurate information being provided.
(1.1) Identify the differences between conifers and flowering plants
GYMNOSPERMS: Mostly evergreen Woody Perennials Produces cones Naked seeds (not in an ovary)
ANGIOSPERMS: Evergreen and deciduous Herbaceous and woody Annual, biennial + perennial Produces flowers + fruits Seeds enclosed in ovaries
(1.1) Describe the differences between MONOCOTYLEDONS and dicotyledons:
Features of root, stem, leaf, flower and seed including internal arrangements of vascular bundles in stems and roots.
(NOTE: I have split this question up due to the amount of information contained in the answer. The term(s) highlighted in CAPITALS are the focus of the answers required for this individual flash card)
MONOCOTS:
Primary root develops fibrous adventitious roots.
Root vascular bundles in circular arrangement.
Soft tissue stems, no lignification.
Stem vascular bundles scattered with no cambium, defined cortex or stele.
Leaves long/oblong with parallel veins, grows from bottom up, sheathing frequent.
Flower petals in multiples of 3’s.
1 furrow in pollen.
Only 1 cotyledon present in seeds.
(1.1) Describe the differences between monocotyledons and DICOTYLEDONS:
Features of root, stem, leaf, flower and seed including internal arrangements of vascular bundles in stems and roots.
(NOTE: I have split this question up due to the amount of information contained in the answer. The term(s) highlighted in CAPITALS are the focus of the answers required for this individual flash card)
DICOTS:
Primary/tap root persists with smaller lateral roots.
Root vascular bundles lobed/star shaped.
Stems soft or woody with lignification/secondary thickening.
Stem vascular bundles arranged in a ring, with cambium.
Leaves broad with pinnate/palmate veins. Grow from tips out, sheathing infrequent, stalks + stilpules often present.
Flower petals in multiples of 4’s or 5’s.
3 furrows in pollen.
Two cotyledons present in seeds.
(1.2) State the reasons why botanical plant names are important.
Provides stability as Regulated by the ICN (International Code of Nomenclature for Algae, Plants + Fungi.
Internationally used and recognised.
Avoids confusion with common names as these may differ between regions.
Allows for accurate identification + communication.
Each name is unique to a single plant.
(1.2) Describe the binomial system of naming plants.
State the meaning of the terms ‘genus’ and ‘species’ and state how they are written, with reference to THREE plant examples
Comprised of the GENUS + SPECIES
Genus is always capitalised while species is all lower case, common names always all lowercase.
Appears in italic in text, underlined when in script.
GENUS: Is a group within a family that share some similarities that are not immediately obvious and are quite general, a genus can have a wide range of species.
Names are commonly; commemorative after the person that discovered it, descriptive of the plant, derrived from mythology.
SPECIES: Divided by more specific set of similar characteristics within a genus. Interbreeding can happen within a species. Referred to as SPECIFIC EPITHET.
Names are usually informative referrencing; origin/location, habitat, descriptive of the plant
Zea mays (corn) Daucus carota (wild carrot) Picea pungens (blue spruce)
(1.2) Describe the naming of cultivated plants.
State the meaning of the term cultivar and state how it is written with reference to THREE plant examples.
Cultivar is short for short for ‘cultivated variety’. Cultivars keep their characteristics in each generation usually via vegetative propagation thus is a clone of the parent plant.
Cultivar names are given when the mutation occurs due to human influence, usually by hybridisation.
The Cultivar name comes after the Bi-nominal name (genus + species), is capitalised and is in single quotations ‘Example’.
Written in roman type (not italics) and is not underlined in script.
Regulated by the International Code of Nomenclature for Cultivated Plants.
Acer forrestii ‘Alice’
Picea pungens ‘Fat Albert’
Lavandula stoechas ‘Fathead’
(1.3) Describe the stages of the life-cycle of a plant:
seed, juvenile (vegetative), adult (reproductive),
senescence, death and their significance for
horticulture.
SEED: Pollen fertilizes egg. In flowers seed is still attached to the parent plant gaining nutrients, leaves plant with high energy food store to nourish in juvenility. Seelings exhibit vigorous growth of newly divided plant cells and are very susceptible to environmental factors like frost and organsisms like grazing mammals and slugs.
JUVENILE: When seedling puts on rapid vegetative growth at expense of flowering. Juvenile plants can exhibit multiple different growth characteristics such as leaf shape, growth habit, rooting abilities, angle of branches and the presence or absence of thorns.
SIGNIFICANCE: Key time for propagation. Cuttings of juvenile plants root reletively easily vs mature plants which are difficult to root or may not root at all. Plant parts containing meristematic cells can yield juvenile growth with good potential for rooting when cuttings are taken. Some plants do not discard leaves until new juvenile growth is seen like in hedges.
ADULT: when plant reaches maturity and can reproduce. Seasonal, environmental or hormonals changes stops leafy growth and plant grows flowers which develop into fruits when pollinated.
SIGNIFICANCE: Difficult or impossible to propagate from cuttings. Stage where breeders can propagate and hybridise through pollination.
SENESCENCE: Process of aging before death, and point where some perennials go into dormancy. Deciduous trees turn colour due to declining chlorophyll + carbohydrate production before dropping leaves. Older plants may abandon extremities such as entire branches in order to preserve energy in core of plant to live another season.
SIGNIFICANCE: The display of autumnal colour prior to leaf abscission to be considered when designing a garden. Ability to get a third showy season of interest with autumnal colour. Environmental manipulation can prevent senescence and premature senescence often a sign that something is wrong with the plant.
DEATH: End of the living plant. Becomes a foodscource for endetrivore organsisms. Woody plants continue to provide a habitat for mamals, birds + insects.
(1.4) Define the BOTANICAL terms: ‘EPHEMERAL’, ‘annual’, ‘biennial’ and ‘perennial’ and the horticultural
meanings of ‘annual’, ‘biennial’ and ‘perennial’.
TWO plant examples should be known for EACH term.
(NOTE: I have split this question up due to the amount of information contained in the answer. The term(s) highlighted in CAPITALS are the focus of the answers required for this individual flash card)
EPHEMERAL: a plant that goes through many lifecycles in a year. If weather isn’t favourable seeds remain in the ground for the next season. Often presents as weed!
Senecio vulgaris (groundsel), Stellaria media (chickweed)
(1.4) Define the botanical terms: ‘herbaceous’, ‘woody’,
‘evergreen’, ‘semi-evergreen’.
TWO plant examples should be known for EACH term.
HERBACEOUS: A plant with soft tissue that does not form woody structures Daucus carota (wild carrot), Zea mays (corn) WOODY: Plants that lignify and form permanent structures Picea pungens (blue spruce), Acer Forrestii (forrest's maple) EVERGREEN: Plants that retain their leaves throughout the growing season and keep their function Picea pungens (blue spruce), Hedera helix (common ivy) SEMI EVERGREEN: can retain leaves in milder summers/winters but will drop leaves in extreme conditions. Lonicera japonica (japanese honeysuckle), Acanthus millis (big spinach)
(1.4) Define the horticultural terms: ‘tender perennial’,
‘half hardy annual’, and ‘hardy annual’.
TWO plant examples should be known for EACH term.
TENDER PERENNIAL: A perenial that cannot survive frost.
Begonia x semperflorens
Fuscia boliviana
HALF HARDY ANNUAL: Sown under protection early in season and planted out when temperatures are above 5 degrees. Cobea scandens (catherdral bell) Ricinus communis (castor oil plant)
HARDY ANNUAL: An annual that can survive most winter temperatures up to -15 degrees celcius. Echium vulgare 'Blue Bedder' (vipers bugloss) Helianthus annuus (sunflower)
(1.4) Define the terms ‘shrub’ and ‘tree’.
TWO plant examples should be known for EACH term.
SHRUB: Woody perennial. Either evergreen or deciduous. Smaller than a tree with numerous stems from ground level to produce a small crown.
Lavandula stoechas ‘Fathead’ (french lavender)
Prunus luscitanica (portugese laurel)
TREE: Woody perennial. Either evergreen or deciduous. Usually tall with singular or more boles/trunks. Bears crown of branches above for arial canopy. Picea pungens (blue spruce) Acer forrestii (forrest's maple)
(2.1) State the function of: cell wall, cell membrane,
nucleus, vacuole, cytoplasm, chloroplast &
mitochondrion.
(From the outside in)
CELL WALL: Separates cells, rigid in plants. Cellulose can contain lignin.
CELL MEMBRANE: Sits inside of cell wall and controls what passes in and out of cell.
NUCLEUS: contains all cell DNA. Controls cell fuctions by controlling protien production.
VACUOLE: Packets containing cell sap - air, water + dissolved foods. May contain leaf, flower or fruit pigments.
CYTOPLASM: Living part of the cell containing most organelles (chloroplasts + mitochondria)
CHLOROPLAST: Respsonsible for photosynthesis. Produces sugars from Co2, water + light. Has own DNA and contains chlorophyll.
MITOCHONDRIA: Energy storage and location of respiration. Sustains cell metabolic processes.
(2.1) Describe where cell division is located within the
plant - apical and lateral meristems.
APICAL MERISTEMS: At growing tips (shoots or roots). Gives length and height above and below ground. Primary growth leads to formation of permanent tissues.
LATERAL MERISTEMS: allows stems and roots to increase in girth, part of the secondary thickening process. Assossiated with cambium tissue. In dicot stems the cambium is arranged in a ring under the bark.
(2.1) Describe how plants increase in size – cell
division and enlargement.
(NO DETAILS OF
MITOSIS ARE REQUIRED).
CELL DIVISION: cells divide and duplicate themselves. Meristematic cells are undifferentiated and divide rapidly.
CELL ENLARGEMENT: vacuoles take on water to expand before cell wall thickens stretching cell lengthways.
(2.2) State what is meant by the term ‘plant tissue’.
An group of cells of the same type having a common function.
(2.2) Describe the characteristics and function of:
protective (epidermis), meristematic (cambium),
transport (phloem, xylem) and packing
(parenchyma) plant tissues.
PROTECTIVE: The EPIDERMIS is a protective layer of cells that forms a boundary between the plant and external environment. Covered in a waxy culticle that reduces water loss and protects agains fungal attack. Includes differentiated cells like guard cells and epsidermal hairs.
MERISTEMATIC: The growth tissue made up of rapidly diving cells - the apical meristems (CAMBIUM) which divide to form phloem, xylem and cork cambium.
TRANSPORT: Cells tightly packed and straw-like for transport. the XYLEM takes UP water and nutrients, PHLOEM conducts food from leaves UP and DOWN to the rest of the plant.
PACKING: The PARENCHYMA found in mesophyll are simple cells, templates for more specialised cells. Used for packing and maintaining shape. They contain large vacuoles and thin flexible walls- the site of metabolic activities.
(2.3) State the primary functions of the root.
Anchors plants in soil.
Absorbs and conducts water water and nutrients up to the plant.
Often acts as a food store.
(2.3) Describe root types - ‘tap’, ‘lateral’, ‘fibrous’ and
‘adventitious’, to include the origin of each type.
TAP ROOTS: Develop from radicle with a large single root growing downwards due to gravity.
LATERAL ROOTS: Smaller branching roots from tap root.
FIBROUS ROOTS: Replaces primary/tap root and are numerous and equal in size. Typical growth of monocotyledons.
ADVENTITIOUS ROOTS: The term used to describe a plant organ (not just roots) when produced in an abnormal position or unusual time of development. Can grow from variety of locations; near vascular tissue, upright stems, nodes on horizontal stems and underground stems. Of great import in propagation with cuttings.
(2.3) Describe the difference between monocotyledon
and dicotyledon roots.
MONOCOTS: Primary root replaced with shallow, fibrous roots. Vascular tissues arranged in a ring around central pith. Roots have no cambium.
DICOTS: Primary tap root persists and grows deep with smaller branching lateral roots. Xylem vascular bundles are lobed/star shaped in the centre of stele. Roots have no pith but have cambium.
(2.3) Describe the structure of the root and state the
function of its components - internal and external
structures to include drawings of transverse and
longitudinal sections through a young dicotyledon
root to show the following components: root cap,
apical meristem, zone of elongation, zone of
differentiation, root hairs, epidermis, cortex,
endodermis, pericycle, phloem, xylem and
cambium.
ROOT CAP: Cells that are sacrificed and contantly replaced from apical meristem for protection as root pushes through soil.
APICAL MERISTEM: The growing tip, produces cells in two directions, to elongate the root and sacrificial root cap cells.
ZONE OF ELONGATION: Behind the cap and meristematic area
ZONE OF DIFFERENTIATION: Behind the zne of elongation where rooot hairs arise and penetrate between soil particles.
From outside to centre:
ROOT HAIRS: Epidermal extensions that increase surface area for water and nutrient absorbtion.
EPIDERMIS: Sinlge layer of cells outside of the root that protects it.
CORTEX: Loosely packed parenchyma cells that allow easy movement of water and oxygen. Storage.
ENDODERMIS: Layer of cells between cortext and pericycle. Semi permeable membrane that controlls movement of water across root before moving up the plants vascular system.
PERICYCLE: Cells surrounding the xylem and phloem for support and protection.
PHLOEM: Conducts food from leaves up and down plant to all parts of the plant.
CAMBIUM: Cells between xylem and phloem that retain ability to divide to create sexondary xylem and phloem.
XYLEM: Conducts water and nutrients up the plant from the roots.
(2.3) Describe how the root is adapted to perform other
functions - storage/perennation, tap root and root tuber, climbing and support/prop.
PERENNATION: Swollen roots act as a storage for biennial plant, resources stored are used in second growing season for flowers and seed production.
TAPROOT: Daucus carota subsp. sativus (carrot)
TUBER: Dahlia pinnata
CLIMBING: Plants can produce secondary adventitious roots from stems aloowing plants to climb or compete for light. These can maintain a week shoot system that is supported at intervals by secondary root systems.
ADVENTITIOUS: Hedera helix (common ivy)
SUPPORT/PROP: Some tall plants develop roots from the stem which appear above ground but anchor back down into the soil propping the plant and providing addition support. Zea mays (corn)
(2.4) State the primary functions of the stem.
The stem hold leaves and flowers in optimum positions for light absorbtion and pollination and transports food, water and nutrients between roots and leaves.
(2.4a) Describe the structure of the stem and state the
functions of its components - internal structures to
include drawing of a transverse section through a
young dicotyledon stem to show the following
components: epidermis, cortex, vascular bundle, phloem, cambium, xylem, pith.
From outside to centre:
EPIDERMIS: Protective cells around the stem.
CORTEX: Packing Cells (parenchyma)
PHLOEM: Transports food up and down
CAMBIUM: Meristematic cells (secondary growth)
XYLEM: Transports water up the plant from the roots.
VASCULAR BUNDLE: Phloem | Cambium | Xylem
PITH: Central part of the stem (parenchyma)
(2.4b) Describe the structure of the stem and state the
functions of its components - external
structures to include lenticels, nodes, axillary and
apical buds, scars (scale and leaf).
LENTICLES: Pores on stem for gas and oxygen exchange for internal tissues.
NODES: Part of stem where leaves emerge, usually a slight swelling or knob.
APICAL BUDS: The undeveloped shoot where embryonic leaves or flower parts arise. Apical buds are found at the growing tips (apex) of the stem.
AXILLARY BUDS: The undeveloped shoot where embryonic leaves or flower parts arise. Axillary buds are found in the leaf axis.
SCARS: Bud scales are a protectve layer on buds found on some temperates zone trees or shrubs.
Leaf scars are found on stem where old leaves have fallen off, marks the site where the petiole was attached to the stem.
