Botany II

Course CodeBSC204
Fee CodeS3
Duration (approx)100 hours
QualificationStatement of Attainment

Learn How Plants Grow

  • What  causes Flowering to occur?
  • What causes roots to form?
  • What causes plant growth to speed up or slow down?
  • What causes fruit to develop? 

Learn the principles and practices of plant physiology for a deeper insight into how plants function,  their growth, factors that promote development and which hinder growth. This course is for people that work or wish to work with plants or as a scientist (eg. for nursery personnel, technicians and researchers and science students wishing to further their knowledge in plant physiology).

Lesson Structure

There are 10 lessons in this course:

  1. Flower physiology
    • Introduction
    • The flowering response
    • Genes control flowering
    • Physiological age
    • Minimum leaf number
    • Photoperiodism
    • Terminology
  2. Phytochrome
    • Light sensing systems
    • Blue light responses
    • Red light responses
    • Other light responses
    • Phytochrome
    • Photoreceptor forms: Pr, Pfr
    • How molelcules changeRelevance to commercial horticulture
    • Controlling light
    • Terminology
  3. Phytoperiodism
    • Light
    • Measuring light
    • What wavelengths do plants need
    • Typical photoperiod responses
    • Photoperiodic responses in seasonal flowering plants
    • Photoperiodic classification of plants: short day plants, long day plants, day neutral plants
    • Detection of photoperiod
    • Critical photoperiod and flowering
    • Research facts
    • Other photoperiodic effects
    • Terminology
  4. Control of flower bud initiation and development
    • Stages in flower bud growth
    • What can affect flower bud initiation
    • Differentiation
    • Dvelopment
    • Anthesis
    • Effect of temperature on growth and flowering
    • VernalisationThermoperiodism
    • Research reports or reviews of specific plants
    • Terminology
  5. Dormancy
    • Dormancy in plants
    • Abscisic acid and dormancy
    • Breaking dormancy
    • Dormancy in seeds
    • Factors affecting seed dormancy
    • Breaking seed dormancy
    • Terminology
  6. Effects of plant associations and competition
    • Introduction
    • Competition
    • Parasitism
    • Coevolution
    • Mutualism
    • Plant herbivore and pathogen interactions
    • Crop spacing and crop yeilds
    • Crop canopy and plant density
    • Impact of weeds
    • Protected environments
    • Greenhouses
    • Shadehouses
  7. Respiration and post harvest physiology
    • Respiration
    • Glycolysis
    • Aerobic respiration
    • Anaerobic respiration
    • Bioluminescene and Fluorescence
    • Post harvest respiration
    • Terminology
  8. Post harvest storage, transport, retailing and shelf life
    • Effect of growing conditions on post harvest life
    • Controlled storage conditions: temperature, atmosphere, humidity
    • Normal atmospheric conditions
    • Controlled and modified atmospheres
    • Effect of oxygen levels Effect of carbon dioxide levels
    • Ethylene
    • Controlling ethylene levels
    • Modified Atmosphere Packaging
    • Commodity transport
    • Retailing and shelf life
  9. Endogenous and synthetic growth regulators
    • Nature of plant hormones
    • Auxins: IAA, IBA, NAA
    • Gibberellins: natural and synthetic
    • Cytokinins: over 130 different types
    • Abscisic acid
    • Ethylene
    • Other homones: anti auxins, growth inhibitors, growth retardants, defoliants, growth Stimulators, non standard hormones
    • Controlled ripening and degreening
    • Waxing
  10. Risks involved with plant growth manipulation
    • Commercial risks
    • Human health and safety risks
    • Plant pathology risks
    • Ecological risks
    • Genetic modification
    • Benefits
    • environmental hazards
    • Human hazards
    • Terminology

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

  • Investigate the physiology of growth development and flowering.
  • Examine the nature of phytochrome and its effect on flowering in the phytochrome reaction.
  • Examine the photoperiodic responses of flowering plants to differing dark and light periods.
  • Examine the effect of temperature on the onset of flowering and flower development.
  • Understand and describe the causes of dormancy in seeds and plants and describe the methods of breaking dormancy.
  • Understand plant associations and competition and their effects on quality and marketable yield.
  • Explain the process of respiration in plant cells and its effect on post-harvest storage and transportation of crops.
  • Describe physiological processes in post-harvest crops in relation to the storage conditions.
  • Investigate the effect on plants of endogenous and synthetic growth regulators.
  • Understand risk assessments relevant to plant growth manipulation.

How Do Plants Grow?

Plant growth is the process by which a plant increases in size, creating more leaves and stems. Plant development is the process by which plants change from one stage of growth to the next. These stages include juvenility, maturity, flowering and seeding. Plant development involves differentiation of the plant into specialised parts. This may include visible changes such as the structural organisation of the plant and new patterns of growth as well as less visible changes such as localised biochemical and metabolic activity.

 

Growth and development are characteristics not only of the entire plant, but also of each cell within that plant. Active cell division occurs in parts of the plant called meristems. Cell division results in growth in length and diameter of the plant, and in the differentiation of specialised plant organs. Differentiation results in the development of individual plant parts such as stems, leaves, new shoots, flowers, fruits, seed and other structures.

 

 

THE FLOWERING RESPONSE

For plants to flower they must first go through a vegetative phase, during which the main processes are elongation of the stem and roots and increase in stem girth. The end of the vegetative phase is marked by flower initiation, whereby the vegetative shoot apex undergoes a sequence of physiological and structural changes to become a reproductive apex (reproductive apical meristem – that which develops into a flower or an inflorescence). The transition from a vegetative to a floral apex is often preceded by an elongation of the internodes and the early development of lateral buds below the shoot apex. The apex undergoes a marked increase in mitotic activity, accompanied by changes in dimensions and organisation. The development of the flower or inflorescence terminates the meristematic activity of the vegetative shoot apex. When these flowers are formed, the plant is prepared for sexual reproduction.

 

Inasmuch as the reproductive apex exhibits a determinate growth pattern, flowering in annuals indicates that the plant is approaching completion of its life cycle. By contrast, flowering in perennials may be repeated again and again.

 

The period from germination to the time the seedling becomes established as an independent organism constitutes the most crucial phase in the life history of the plant. During this period, the plant is susceptible to injury by insect pests and parasitic fungi, and water stress can very rapidly result in death.

 

The stimuli for flower induction includes hormonal changes and environmental changes, such as day length (photoperiod) and temperature.

 

Enrol and study this course for a deeper understanding of how plants grow