2.3 Flashcards
Micropropagation
Technique of plant propagation using extremely small parts, tissue or organs of plants, placed and grown in suitable sterile environment/culture to produce new plants.
Totipotency
Capacity for differentiated cells to regenerate whole new plants.
It is possible because all cells contain a complete set of genetic information necessary to form a new plant.
Being totipotent means that many techniques using a variety of plant cells can be used for tissue culture.
Plant selection for micropropagation.
Plant selection taken from an intact plant in sterile condition.
Free from pests, fungi and diseases.
Once plant material is chosen collection of explant begins; this is dependent on the type of tissue to be used.
Explant
Tissue selected from a plant from which new cells are multiplied to provide material for micropropagation.
Preparation of explant.
Explant material needs to be fully sterilized across it’s surface.
This usually dine with bleach and alcohol washes and final wash and rinsed in sterilised water.
Portion of plant tissue (maybe single cell) is placed in growth medium.
Growing medium usually contains sucrose as energy source and plant growth regulators.
Medium is usually thickened with agar to create gel to support explant.
Use of PGRs (plant hormones)
On plant medium plant tissue will start to grow and differentiate into tissues, depending on medium and types of hormones used.
Eg media containing cytokinins is used to create branched shoots from plant buds.
Multiplication in micropropagation
Growing explant creates large amount of differentiated tissue which is then multiplied. Multiplication is the taking of this tissue and using it to increase numbers of plant tissue,
Micropropagation
Weaning off
Preparation of plants produced by micropropagation for natural growth.
Necessary as plants have been produced in highly protected environments resulting in soft, vulnerable growth.
Plants often don’t have functional dermal coverings and are highly susceptible to disease. Because of high humidity environment cuticle and stomata have not formed.
Hardening up involves slowly weaning the planlets from a high-humidity, low light, warm environment to ‘normal’ growth environment..
Micropropagation
Transplanting
The final stage of micropropagation.
Once plantlets have been weaned off they are removed from growing Mia and transferred to potting compost to continue growth in more conventional environment.
Micropropagation
Uses in Commercial horticulture
Propagation of difficult to propagate plants eg. Orchids
Quick increase of commercial stock eg. Pot plants such as Gerbera or strawberry runners.
Producing virus free stock - eg. Soft fruit plants such as strawberries and apple rootstocks
