Leaving Certificate Agricultural Science

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Leaving Certificate Agricultural Science
Plant Science
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Learning Outcomes....

• In this unit you will learn about
• Plant and animal cells
• Structure of a plant (leaf, stem , root, etc)
• Photosynthesis, Respiration, Osmosis,
  Translocation, Active Transport, etc.
• Sexual Reproduction in a flowering plant.
• Plant hormones
• Food Biomolecules and their tests.

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Cell Types

• Plant Cells
• Has a cell Wall
• Has a large Vacuole
• Has Chloroplasts

• Animal Cells
• Has no cell wall
• Has small vacuoles
• Has no Chloroplast

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Leaf Functions

• Photosynthesis
• Transpiration
• Gaseous Exchange
• Food Storage

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Stomata- Gaseous Exchange
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Gaseous Exchange in Stems

• Lenticels-Gaseous Exchange in Stems

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Learning Check...

• State 3 differences between plant and animal
  cells.
• Give 4 functions of a leaf.
• Where does gaseous exchange take place in the
  leaf?.
• Where does gaseous exchange take place in the
  stem?.

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Photosynthesis
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Outline of Photosynthesis
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Experiment
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Transpiration

• Is the loss of water vapour from the surface of
  the leaf of the plant

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Transpiration (Video)
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Investigating Transpiration
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Transpiration Experiment
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Translocation

• The movement of food around the plant.
• Phloem tissue
• In both directions
• Sugar is transported from the leaf to the root.
  Beet root.
• Vascular Tissue
• Xylem- transports water and minerals.
• Phloem- transports food.

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Cells and Tissues

• Parenchyma Cells-Photosynthetic Cells
• Schlerenchyma Cells- Strengthening Cells
• Collenchyma Cells- Strengthening Cells
• Meristematic Tissue- cell Division
• Ground Tissue- bulk of cell. Photosynthesis takes
  place here.
• Vascular Tissue- Transport tissue
• Xylem- Transports Water and Minerals
• Phloem- transports food

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Learning Check....

• State the balanced chemical equation for
  photosynthesis.
• Define the term Transpiration.
• Define the term Translocation.
• Name 2 types of vascular tissue and give their
  functions.
• Name the cells responsible for strengthening?
• Name the cells where photosynthesis takes place?
• Name the cells responsible for cell division

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Functions of the stem

• 1. Transports water, minerals from the roots.
• 2. Transports food from the leaf
• 3. Supports the aerial part of the plant
• 4. Stores food e.g. potatoes

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Stems

• T.S. Monocot

• T.S. Dicot

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T.S Root

• Functions
• Food Store
• Anchorage

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Osmosis

• Is the movement of water from an area of high
  concentration of water to an area of low
  concentration of water across a semi permeable
  barrier

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Osmosis (Animation)
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Diffusion

• Is the movement of gases from an area of high
  concentration to an area of low concentration.

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Active Transport

• Is the movement of substances from an area of low
  concentration to an area of high concentration.
  It requires energy.

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Active Transport (Animation)
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Learning Check...

• Give functions of the root
• Give functions of the stem
• Define osmosis, active transport and diffusion.
• Compare Monocots to Dicots.

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Pollination

• Is the transfer of pollen from the anther of one
  plant to the stigma of another plant
• Self Pollination when pollination occurs
  between flowers on the same plant.
• Cross Pollination- when pollination occurs
  between flowers of the same species but on
  different plant.

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Pollination Types

• Insect Pollinated
• Lily
• Large Flowers
• Scented
• Brightly coloured
• Male and female parts
• inside flower
• Sticky pollen grains
• Small pollen grains

• Wind pollinated
• Grass
• Smaller flowers
• Not scented
• Not brightly coloured
• Male and female parts outside the petals
• Smooth Pollen grains
• Large amount of pollen

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Fertilisation

• Is the fusion of the male
• gamete with the female gamete.
• It forms a Zygote

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Development of the embryo, seed and fruit

• The zygote divides repeatedly until it forms the
  embryo that will contain
• 1 or 2 cotyledons with a food store
• Plumule
• Radicle
• The ovary becomes the fruit

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Dispersal

• Is the transfer of the seeds/fruit away from the
  parent plant
• Wind
• Water
• Animal
• Self

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Dormancy

• Where a plant suspends all growth and metabolism
• Shortage of hormones
• Low temperature
• Growth inhibitors
• Maximises growth of the plant.
• Allows for seed dispersal
• Ensures survival

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Germination

• Is the regrowth of a plant after a period of
  dormancy
• Conditions necessary
• Water
• Oxygen
• Warmth

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Germination (Video)
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Learning Check...

• Name the male and female parts of the flower.
• What is a calyx and a corolla.
• Define pollination, fertilisation, dormancy and
  germination.
• Differentiate between self and cross pollination.
• Compare wind pollinated flowers to insect
  pollinated flowers.
• What does a plumule and a radicle develop into?
• Define Dormancy
• List the conditions necessary for germination.
• Describe Epigeal and Hypogeal germination using
  examples.

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Seed Structure
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• If the cotyledons absorb the endosperm the seed
  is NON-ENDOSPERMIC Broad Bean
• If the cotyledons absorb only some of the
  endosperm the seed is ENDOSPERMIC Maize.

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Lifecycles

• Annuals/perennial- Complete their lifecycle in
  one year
• Biennials- it takes 2 years to complete their
  lifecycle. In the first year the plant grows
  leaves, stems, and roots (vegetative structures),
  then it enters a period of dormancy over the
  colder months. During the next spring or summer,
  the stem of the biennial plant elongates greatly,
  The plant then flowers, producing fruits and
  seeds before it finally dies.

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Plant hormone AUXIN

• Naturally produced in the root and shoot tip.
• It promotes cell elongation
• Stimulates fruit development.
• Promotes root development.(rooting agent)
• Control apical dominance
• Its used in seedless fruits Parthenocarpic fruit
• IAA

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Giberellin Cytokinin

• Encourages cell elongation
• Promotes seed germination
• Cytokinin. Used as a herbicide by massively
  increasing rate of growth and the plant cannot
  produce enough food and it dies!

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Tropism

• A growth response to a stimulus.
• Phototropism- A growth response to light
• Geotropism- a growth response to gravity
• Thigmotropism- a growth response to touch
• Chemotropism- A growth response to chemicals
• Hydrotropism- A growth response to water
• Thermotropism- A growth response to temperature.

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Clinostat.
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Respiration- Aerobic/Anaerobic
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To Show Respiring Seeds produce energy.
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Learning Check...

• What is a tropism.
• What is phototropism and geotropism?
• What piece of apparatus is used to show
  geotropism?
• Define Aerobic respiration
• Give a balanced chemical equation for aerobic
  respiration.

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Indicator Species

• An indicator species is a species that shows the
  conditions in habitat.
• Examples
• Wet rushes, moss, buttercup.
• Dry/Sandy Thistle.
• Low in lime (acidic) Plaintain/rhododendron
• Rich in Lime (alkaline) Clovers, Chickweed.

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Food Tests
Starch Protein Reducing Sugar Vitamin C Sugar
Reagent Iodine Biurets Benedicts Reagent DCPIP Refractometer
Source Potato, Starch solution Peas, Milk Glucose Solution Orange Grass, beet, etc.
Initial Colour Golden Brown Blue Blue Blue
Positive Colour Blue Black Purple Brick Red Yellow