Foundation Certificate in Plant Growth for Horticulture Level 3

Understand the principals of plant growth.

This 200 hour course will provide the student with a comprehensive learning in plant growth, health and propagation.

• Develop your ability to describe the principles of plant taxonomy, structure, function and growth, the management of plant health, and plant propagation.

Lesson Structure

There are 15 lessons in this course:

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

• Demonstrate knowledge of the major divisions of the plant kingdom and an understanding of the taxonomic hierarchy and its relevance to horticultural practice.
• Identify and describe the different types of plant cells and tissues, their structure, and function.
• To understand the role and function of the reproductive parts of the plant and the seed in the plant lifecycle.
• Understand the mechanism and role of photosynthesis and respiration in the metabolism of plants, the role of water in the plant, and the movement of water, solutes, and assimilates through the plant.
• To develop an understanding of the effects of tropisms and other plant movements on growth and development.
• Understand the physical properties of growing media and their significance in relation to plant growth.
• To understand basic chemistry of soils and other growing media, and the relationship between their air and water content and plant growth.
• To understand the role of living organisms in the biological processes of soils and other growing media.
• To understand how nutrients affect plant growth and describe a range of fertilisers and their applications.
• To determine appropriate management programs for different soils in horticultural situations.

Course Duration: 200 hours

1. Roots (the parts which generally grow below the soil)
2. Stems (the framework that sits above the roots)
3. Leaves (parts attached to the stems that are required for respiration, transpiration and photosynthesis)
4. Reproductive Parts (flowers and fruits).

Most flowering plants are dicotyledons. They are so called because the embryo within the seeds of these plants contains two separate seed leaves (cotyledons). Conversely, the seeds of monocotyledons contain only one seed leaf. Other differences include the fact that in monocotyledons the vascular bundles used for the transport of food and fluids are closed systems that are scattered within the stem, whereas in dicotyledons they are arranged in a single ring within the stem. Also, the leaves of monocotyledons have parallel veins and typically have no midrib (central vein) whereas those of dicotyledons have a network of veins with a distinct midrib. The few woody species of monocotyledons have no bark but their many dicotyledonous counterparts all have bark. Furthermore, the pollen grains of monocotyledons have just one furrow whereas those of dicotyledons have three furrows.

Of more importance to this lesson, is the difference between the flowers of monocotyledons and dicotyledons. The flower parts of monocotyledons are arranged in groups of three and they usually have three or six petals. Those of dicotyledons are arranged in groups of four, five, or very rarely, two. Monocotyledons are estimated to account for around a quarter of all flowering plant species and include: grasses, reeds, rushes, palms, lillies, and orchids. Even the most complex orchid flowers still have the characteristic monocotyledonous arrangement of flower parts in groups of three, although it may be difficult to discern. 
    

THE FLOWER

The function of flowers is to produce seed, thus allowing plants to reproduce sexually.  Flowers are made up of whorls of four parts:

• Sepals – these are usually green, and they protect the other parts of the flower.  Collectively, sepals are known as the calyx.
• Petals – the petals are usually the showy part of the flower, and collectively, the petals are known as the corolla.  The calyx and corolla together are known as the perianth. In monocotyledons, the petals and sepals are indistinguishable and are individually known as tepals.
• Stamens – the stamens consist of the anther and filaments (stalks).  The anthers hold pollen.  The stamens are the male part of the flower, and collectively are known as the androecium.
• Carpels – in the center of the flower is the female part: the gynoecium.  It consists of one or more carpels.  A single carpel is made up of a stigma, style and ovary.  The term pistil is used ambiguously to describe either a single carpel or a group of fused carpels.

These four main flower parts are arranged from the flower base or receptacle (tip of the flower stalk).  An important distinction in flowers is whether the ovary is inferior or superior.  Flowers in which the floral parts (i.e. sepals, petals and stamens) are inserted onto the receptacle below the ovary are said to have superior ovaries.  Where a flower has the receptacle fused to the sides (and often over the top) of the ovary, the ovary is said to be inferior.  Where a receptacle is fused only part way up the ovary wall, it is known as half inferior.

The Inflorescence

Some flowers are borne singly on a stalk.  These are solitary flowers e.g. lily.  Others, however, are borne in groups known as inflorescences e.g. sunflowers. Sometimes, it is difficult to tell the difference between the two, especially when the individual flowers are very small.  For example, members of the daisy or Asteraceae family such as the aforementioned sunflower have a composite head which looks like one large flower but which, in actual fact, is a collection of many small flowers surrounded by specialised 'ray florets' which look like petals. The outer ray florets are sterile whereas the inner 'disc' florets mature into seeds.

The stalk of an inflorescence or a solitary flower is known as a peduncle.  The stalk of an individual flower in an inflorescence is a pedicel.  The main types of inflorescences are as follows:

• Panicle - this is a highly branched inflorescence.
• Umbel - an inflorescence in which the individual flower stalks arise from the one point at the tip of the stem. They are typically flat-topped.
• Composite Head (Capitulum) - an inflorescence composed of many small, tightly packed sessile (not stalked) flowers, such as a sunflower and other members of the Asteraceae family.
• Raceme - a simple elongated inflorescence in which the flowers appear on stalks.
• Cyme - a dome-shaped or flat-topped flower head in which the inner flowers open first.
• Corymb - a dome shaped or flat-topped flower head in which the outer flowers open first.
• Spike - a simple elongated inflorescence comprised of sessile flowers.
• Catkin - a typically densely packed spike, or spike-like raceme of miniature bracted flowers (or fruits).
• Compound Umbel - comprising of two or more umbels.
• Plume (Capitulum) - a dense, feathery, branched arrangement of flowers on the stalk.
• Whorl (Verticallaster) - three or more flowers (or leaves) arranged in a circle arising from one central location on the stalk.

REPRODUCTION

Seed is produced by pollen from a flower (i.e. the male part of the flower) fertilising the ovary of a flower (i.e. the female part).  Refer to the flower structure diagrams in this lesson. If the pollen comes from the same plant (i.e. self-pollinating) as the ovary, then the seed will grow into a plant identical to the parent plant. If the pollen and ovary come from two different plants (cross pollination), the seed will grow into a plant which will be a mixture of characteristics from the two parents. 

• Self pollinating – pollen is transferred, on the same flower and the same plant, from the male anther to the female stigma. This means that genetic diversity can be maintained with fewer plants and less distance is required between varieties of the same species to make sure of genetic diversity. Beans and tomatoes are examples of self-pollinating types.
• Cross pollinating – pollen is transferred from the anther of one plant to the stigma of a different plant through wind, insects or by hand-pollination. Constant inbreeding between cross-pollinators can lead to a loss of vigour and quality in following generations. To prevent this, cross pollination of varieties within the same species should be avoided.