Transcript Unit 17 Agriscience Plant Reproduction - BROADUS

Unit 17 Agriscience
Plant Reproduction
The reason plants do such a good job of surviving all the problem
That the environment throws at them is that they do such a good
Job of reproducing. Reproduction using many methods have given
Them the ability to adapt. The first ideas of cloning and genetic
Manipulation came from the study of the vegetative reproduction
Of plants.
Propagation or reproduction – increasing the number of a
Type of plant by Sexual or Asexual means. Sexual reproduction is
The formation and union of gametes. Sexual reproduction allows us
To crossbreed plants to increase vigor. Asexual reproduction,
vegetative, is using parts or a part of a plant to produce another plant.
Sexual Reproduction
A seed has stored food in it and remains dormant until germination.
The following conditions are necessary for germination.
Water – (imbibition) activates enzymes that starts the usage of the
food
Some seeds need to be scarified the nicking of the seed coat so they
Can absorb water.
All living (viable) seeds respire and need oxygen.
Some seeds need light to aid the process of germination
The correct temperature is needed for the germination process
To take place each species requires a different temperature. If soil
Conditions are too cold seeds may rot before they germinate.
Asexual Reproduction
The processes of asexual reproduction is used extensively in the
Greenhouse industry.
Stem cuttings- can be made on herbaceous anytime while woody plants
Need to be done in the fall. It requires the use of a rooting hormone
And growth medium.
Tip cuts – a long stem that has a terminal bud
Section cut – taken from the middle of a stem with no terminal bud
Cane cut – section of stem placed in a horizontal position
Heel cut – a football shaped section cut out with a bud on it
Single eye cut – one bud per cut
Double eye cut – two buds per cut usually used on alternate leaf plants
Asexual Reproduction cont.
Leaf cutting is another method of propagating plants. This can only
Be used on herbaceous plants.
Leaf – A leaf without a petiole is placed vertically in the growth
medium
Leaf petiole – petiole of the leaf is placed in the growth medium
Leaf section – a leaf is cut into wedge shape each containing at least one
Vein.
Split vein – open a vein in a leaf turn leaf upside down and place it
in the growth medium.
Asexual Reproduction cont.
Root cuttings – can only be done when plants are dormant, the
Roots are actually cut.
Layering is done when the stem comes into contact with the growth
Medium.
Simple – The stem is made to contact the medium
Tip – bend the stem and place the tip into a hole in the medium
Air – splitting of bark, hormone applied and then covered
Divisions – separating crowns like strawberries
Grafting – the Scion is the top part that is grafted onto the root stock.
The union is the place where the two parts meet. When grafting care
Must be taken to make sure the cambium layers touch and that the
Wound is protected from insects and disease.
Asexual Reproduction cont.
Grafting continued
Bud – a small piece of bark is cut with a bud on it to be placed
On another stem
T- bud – t cut in the root stock and a shield shaped bud is placed in
Tissue Culture
This is the process of using a specialized part of a plant to create
A new plant in sterile conditions so no diseased associated with
The original plant. It may be called micro-propagation. Used
exclusively in seed potato production.
This process is very expensive and time consuming also the following
Areas must be done.
Everything must be clean and sterile
Clean plant tissue must be collected
Multiplication medium must be used usually agar.
Transplant medium must be used
Sterile glassware must be used
Sterile tools must be used
Scalpels must be used to make clean cuts.
Cloning
This is the process of tissue culture where a single cell is used
From a parent plant to create a genetically exact copy of that plant.