PLANT REPRODUCTION

1
PLANT REPRODUCTION

• Environmental and Agricultural Science

2
INTRODUCTION

• Propagation or Reproduction is simply the process
  of increasing the numbers of a species.
• Two types of propagation are sexual and asexual.

3
INTRODUCTION

• Sexual reproduction is the union of an egg
  (ovule) and sperm (pollen), resulting in a seed.
  Two parents creating a third individual is
  referred to as sexual propagation.
• Asexual reproduction uses a part or parts of only
  one parent plant. The new plant is a clone or an
  exact duplicate of its parent. This type of
  reproduction uses the vegetative parts of the
  plant, mostly stems, roots or leaves, so it is
  referred to as vegetative propagation.

4
ADVANTAGES OF SEXUAL PROPAGATION

• Less Expensive
• Quicker than some other methods
• Only way to obtain new varieties and capture
  hybrid vigor
• Avoids passing on some diseases
• For some plants, it is the only way to propagate
  them
• Hybrid vigor-refers to the tendency for hybrid
  plants to be stronger and survive better than
  purebred plants.

5
ADVANTAGES OF ASEXUAL PROPAGATION

• In some cases easier and less expensive
• Plants are identical to parent plants
• In some species, it is the only way to propagate
  them

6
SEXUAL PROPAGATION

• Parts of a Seed
• Seed Coat protects the seed
• Endosperm food reserve
• Embryo young plant

7
GERMINATION

• Germination to start to grow or sprout
• Must be in certain favorable conditions for
  effective germination
• Water absorption of water is the first step in
  germinating process
• Moist germination medium

8
GERMINATION

• Air Respiration takes place in all viable
  seeds. Oxygen is required.
• Respiration increases as the germination starts.
• Viable alive and capable of germinating
• Light Some seeds are stimulated to grow by
  light. Some are inhibited by the presence of
  light.
• Temperature Germination rate and the percentage
  of seed that germinates are affected by the
  availability of heat. Some seeds germinate over
  a wide range of temperatures, while others have
  narrower limits.

9
How do you scarify a seed with a hard seed coat?

• Scratch or nick it with a knife or file.
• Soak seeds in concentrated sulfuric acid.
• Place seeds in hot water and allow to soak.
• Place seeds in a warm, damp container.

10
Asexual Propagation

• Primary Methods cuttings, layering, division,
  grafting and tissue culture.
• Stem Cuttings
• Herbaceous and woody plants are often propagated
  by cuttings (vegetative parts that the parent
  plant uses to regenerate itself).
• Types of cuttings are named for the parts of the
  plants from which they come.
• They are stem tip cuttings, stem cuttings, cane
  cuttings, leaf cuttings, leaf petiole cuttings
  and root cuttings.

11
Cuttings Procedure

• Procedure is simple.
• Need sharp knife or razor blade
• Clean knife or razor blade with bleach or rubbing
  alcohol
• Flowers and buds should be removed
• Allows cutting to use its energy for food storage
  and root formation instead of flower fruit
  development
• Rooting hormone is used to stimulate root
  development
• Place cuttings in a medium of sand, perlite,
  soil, a mixture of peat and perlite or
  vermiculite
• Keep medium moist

12
Cuttings

• Leaf-type Cuttings
• Produces herbaceous plants quickly and
  efficiently.
• Will not normally work for woody plants
• Root Cuttings
• Best to use plants that are at least 2-3 years
  old
• Should be taken in the dormant season when the
  roots have a large supply of carbohydrates in
  reserve

13
Layering

• Layering
• Stems will develop roots in any area that is in
  contact with the medium while still attached to
  the parent plant.
• After roots form, shoots develop at the same
  point.

14
Division

• Division
• Propagating plants by dividing or separating the
  main part into smaller parts
• Used with plants that have crowns, corms, or bulbs

15
Grafting

• Grafting
• Procedure for joining two plant parts together so
  they grow as one
• Used when plants do not root well as cuttings or
  when a plants root system is unable to support
  the plant for good growth
• Allows production of unusual combinations of
  plants (several varieties of apples can be grown
  on one tree)