Plant Biotech (conditions for PTCs)

Question 1

What are the conditions of PTCs?

Answer 1

Light, temperature, humidity, growth medium, pH, plant growth regulators (PGRs)

Question 2

What are the conditions for light?

Answer 2

Light is on for the standard photoperiod of 16hrs (NOT 24hrs) to allow plants to respire

Photosynthetic lvls in vitro are low and effects of light are morphogenic (i.e. affects shape of plant)

Question 3

What are conditions for temp and humidity

Answer 3

Temp: 22 ℃ to 27 ℃ for in vitro growth
Humidity: maintained above 80% relative humidity

Question 4

What are the conditions for the growth medium?

Answer 4

Like bacteria culture medium (in microbial tech) there are:
macronutrients at high conc
micronutrients at low conc
vitamins
energy source

purpose: used as building blocks for synthesising molecules, catalysts of reactions, osmotic reactions

Question 5

What are conditions for pH?

Answer 5

pH MUST be appropriate to stimulate an internal environment within the plant cell

Optimum range is pH 5.0 - 6.0
If > pH 6.0 = poor diffusion of nutrients into tissues
If < pH 5.0 = poor gelling of agar (agar doesnt become hard)

Question 6

What are the plant growth regulators and their main effects

Answer 6

Auxins and Cytokinins

Auxins main effects:
- induces cell division
- induces root formation
- induces callus formation and growth
- inhibits outgrowth of buds (i.e. shoots)

Cytokinins main effects:
- induces cell division
- induces shoot formation
- induces callus formation and growth
- inhibits root formation

Question 7

What happens if theres a high auxin to cytokinin ratio (i.e. more auxin)

Answer 7

root formation

Question 8

What happens if theres a low auxin to cytokinin ratio (i.e. more cytokinin)

Answer 8

shoot formation

Question 9

What happens if both auxin and cytokinin have the same amt?

Answer 9

callus formation