Lecture 23: Abiotic Environment - 12/1

Question 1

What are 5 examples of abiotic stress?

Answer 1

Temperature, moisture (water/relative humidity), solar radiation, atmosphere, nutrient availability

Question 2

Stress

Answer 2

Any environmental condition that prevents the plant from achieving its full genetic potential

Question 3

Acclimation

Answer 3

When a plant redirects its flow of energy in response to stress, establishing a new state matched to the specific stress conditions

Question 4

Reactive oxygen species

Answer 4

Highly reactive forms of oxygen that rapidly react with and oxidize a wide variety of cellular components.

They are one of the most common group of toxic molecules

Question 5

What can happen to a plant/produce if temperatures are too high or low?

Answer 5

A chilling/high temperature injury

Question 6

What is the negative effect of freezing on plant tissue?

Answer 6

Damage due to dehydration

Question 7

Why does freezing cause dehydration in plant cells?

Answer 7

Because ice crystals form in the cell wall, making the solution more concentrated there

Water then moves from inside the cell to the cell wall to re-establish osmotic equilibrium, dehydrating the cell as a result

Question 8

Why do core tissues in fruit freeze first?

Answer 8

Because the soluble solids content is lower close to the pit

Question 9

BRIX

Answer 9

Each degree brix is equivalent to 1% sugar concentration when measured at 20°C

Question 10

How have global CO2 concentrations increased in the last <200 years?

Answer 10

They have increased by 50%