Media Composition

1
Media Composition

• Mineral elements
• Organic compounds
• Support systems
• Growth regulators
• Media formulators

2
Units

• Units -
• mg/l
• mM - macronutrients, organics
• µM - micronutrients, hormones, vitamins, some
  organics

3
Macroelements

• Greater than 0.5 mM
• N,K,P,Ca, Mg,S

4
Micronutrients

• Less than 0.5 mM
• Fe, Mn, Zn, B, Cu, Mo, Co, I, (Ni, Al, Si)
• Fe - must be chelated or may not be available to
  plant tissues

5
Organic Compounds

• Sugars - sucrose, glucose, sorbitol
• Vitamins thiamine
• Myo-inositol
• Complex organics - juices
• Activated charcoal

6
Support systems

• Agar - from seaweed
• Gelrite (also known as Phytagel) - from bacteria
• Agarose - highly purified
• Mixtures - Phytagar (Sigma)
• Mechanical - bridges, rafts

7
Growth Regulators
8
Media formulations

• Many available
• Differ in salt concentrations
• Differ in presence or absence of salts
• Differ in pH

9
Storage of Media

• Can be stored up to 1 month
• Must be airtight or evaporation results
• Best if stored in the dark
• Best kept in sterile area

10
Selection of proper media

• How do you select a medium?
• Go to the literature
• Try pre-formulated media
• Alter constituents one at a time
• DeFossard method
• Trial and error

11
How important is media?

• Important for
• Growth
• Organogenesis
• Hyperhydricity
• Rooting
• Survival after culture

12
Comparison of Media