Increasing Plant Production

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Increasing Plant Production

• AS 91290
• Demonstrate understanding of techniques used to
  modify physical factors of the environment for NZ
  plant production

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Contents

• THE BASICS
• Photosynthesis, respiration, transpiration,
  nutrient uptake, water uptake.
• Liebigs Law of the Minimum
• PLANT GROWTH
• Bud formation, flowering, pollination,
  fertilisation, fruit set, germination,
  maturation, ripening.
• ENVIRONMENTAL FACTORS
• light, sunlight hours, temperature (Growing
  Degree Days (GDDs) or heat units (HUs)), frost,
  chill requirements (as expressed by chill units),
  rainfall, humidity, wind, soil type, topography.
• TECHNIQUES (see PPT number 2)
• CO2 enrichment, artificial shelter, sprinkler
  irrigation, tile drainage, hail cannon, wind
  machines, reflective mulch, training systems.

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Plant Processes

• There are 6 key processes that happen inside a
  plant
• Photosynthesis
• Respiration
• Transpiration
• Nutrient Uptake
• Water Uptake
• Fertilisation/pollination Plants having sex to
  produce viable seeds and fruit
• Learn how to spell these!

Converting light energy to chemical energy
Using chemical energy to grow and function
Getting water from the roots to the leaves
Getting macro and micro nutrients into the plant
Getting water from the growing media into the
roots
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Photosynthesis
Light energy chlorophyll
Water Carbon Dioxide ? Glucose Oxygen
H2O CO2 ? C6H12O6
O2
Converted to
Carbohydrates (eg starch)
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Photosynthesis

• Is a chemical reaction occurring in the
  chloroplasts found inside plant cells
• One purpose of the photosynthesis is to convert
  light energy to chemical energy to be used by the
  plant.
• The other purpose is to create the molecule
  glucose that can then be used to build cell
  components

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Capturing Energy

• The chemical energy is initially in glucose but
  the plant converts some of the glucose into
  starch for long term storage.
• The energy is released in respiration to power
  other cell processes such as the formation of
  proteins and lipids.

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Photosynthesis - Chlorophyll

• Chlorophyll is a green pigment inside the
  chloroplasts found in plant cells.
• Chlorophyll is essential for photosynthesis
• What are the essential nutrients needed for
  chorophyll?

You do not need to learn the structure of
chlorophyll
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Photosynthesis light absorption

• So why are plants green?
• Chlorophyll does not absorb green light instead
  it reflects green light and it bounces back off
  the plant into your eye and the plant (leaf)
  looks green.
• So what colour light should plants be exposed to?

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Respiration
Oxygen Glucose ? Water Carbon Dioxide
O2 C6H12O6 ? H2O CO2
Energy released
This energy is the useful output of
respiration The energy is released in respiration
to power other cell processes such as the
formation of proteins and lipids
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Respiration

• The purpose of respiration is to release the
  energy from glucose.
• The water and carbon dioxide are waste products
  and most of the water and carbon dioxide exit the
  plants through the stomata.
• Respiration occurs in all living cells in the
  plant. Consequently oxygen is needed in all parts
  of the plants including the roots

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• Summary diagram showing the relation- ship
  between photosynthesis and respiration

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Transpiration

• Transpiration is the process of water movement
  into the roots. Up the stem and out of the
  stomata in the leaves.

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Transpiration

• Plant transpiration is pretty much an invisible
  processsince the water is evaporating from the
  leaf surfaces, you don't just go out and see the
  leaves "sweating". Just because you can't see the
  water doesn't mean it is not being put into the
  air, though. During a growing season, a leaf will
  transpire many times more water than its own
  weight. An acre of corn gives off about
  11,400-15,100 liters of water each day, and a
  large oak tree can transpire 151,000 liters per
  year.

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Photosynthesis

• Photosynthesis (echalk)

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Respiration

• Glucose Oxygen ? Carbon Dioxide Water

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Carbon dioxide (CO2) is an essential component of
photosynthesis (also called carbon assimilation).
Photosynthesis is a chemical process that uses
light energy to convert CO2 and water into sugars
in green plants. These sugars are then used for
growth within the plant, through respiration. The
difference between the rate of photosynthesis and
the rate of respiration is the basis for
dry-matter accumulation (growth) in the plant.
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Dry matter accumulation

• Carbon dioxide (CO2) is an essential component of
  photosynthesis (also called carbon assimilation).
  Photosynthesis is a chemical process that uses
  light energy to convert CO2 and water into sugars
  in green plants. These sugars are then used for
  growth within the plant, through respiration. The
  difference between the rate of photosynthesis and
  the rate of respiration is the basis for
  dry-matter accumulation (growth) in the plant.

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Nutrient Uptake

• Nutrients are up taken via the roots of the
  plant.

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• What is the optimum soil pH range?

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• The plant, through photosynthesis, fixes carbon
  dioxide and water in the form of sugars. The
  sugars are used in respiration to provide energy
  - breaking down again to carbon dioxide and
  water. Some sugars are synthesize into amino
  acids and finally proteins, the building blocks
  of living tissue.

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Liebigs Law of the minimum

• States that growth is controlled not by the total
  of resources available, but by the scarcest
  resource (limiting factor).
• This concept was originally applied to plant or
  crop growth, where it was found that increasing
  the amount of plentiful nutrients did not
  increase plant growth. Only by increasing the
  amount of the limiting nutrient (the one most
  scarce in relation to "need") was the growth of a
  plant or crop improved.

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Liebigs Law of the minimum - explained

• The water level in the barrel represents plant
  growth.
• By adding more light, Phosphorus, warmth etc
  there will be no further increase in growth.
• What is the limiting factor?

Nitrogen
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Effect of Light and Water on Plant Production
Click here for explanation
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Kiwifruit Data Exercise
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Inside a leaf
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Stomata
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Site Establishment
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Pests and Diseases

• Pests and diseases can influence the crop that
  can be grown in a certain region, ie apples
  arent grown in the Waikato and grapes are no
  longer commercially grown in West Auckland due to
  dampness of the climates (botrytis).
• New growth of all plants are very susceptible to
  pests and diseases.
• Pests chew the tender tasty tips of plants
  restricting the development of the plants and
  their ability to carry out plant processes.
• Fungi such as mildew destroy apical buds.
• Pests chew the plants providing an entry point
  for diseases which restricts the ability of the
  plant to grow at an optimum rate.

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Aphids sucking the growing shoot of a rose
Aphids sucking sap from cabbages
Mildew on growing tip
Grass grubs under turf
Clean
Infected
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Plate 1. Carbon dioxide generator.
Plates 6b. Liquid CO2 tanks.

• CO2 Enrichment

Liquid Carbon dioxide tank supplying a greenhouse.
Carbon dioxide generator for a large greenhouse
(burns fossil fuels to generate CO2
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CO2 Enrichment

• Normal CO2 level in outside air is about 340 ppm
  (0.3). All plants grow well at this level but
  as CO2 levels are raised by 1,000 ppm
  photosynthesis increases proportionately
  resulting in more sugars and carbohydrates
  available for plant growth.
• Any actively growing crop in a tightly clad
  greenhouse with little or no ventilation can
  readily reduce the CO2 level during the day to as
  low as 200 ppm. The decrease in photosynthesis
  when CO2 level drops from 340 ppm to 200 ppm is
  similar to the increase when the CO2 levels are
  raised from 340 to about 1,300 ppm

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Fruit Development

• Which of the following Horticultural products do
  not develop from a flower.
• Strawberries
• Bannanas
• Carrots
• Beans
• Peas
• Pumpkin
• Corgetts
• Tomatos

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Fruit Development

• 5 stages of fruit development
• Bud set
• Bud burst
• Pollination/ fertilisation
• Fruit development
• Fruit ripening

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• Link the five stages of fruit development with an
  image
• Bud set
• Bud burst
• Pollination/ fertilisation
• Fruit development
• Fruit ripening
• Then give each a definition

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Environmental factors affecting fruit development