ISA Tree Biology and Physiology 2

Question 1

What is the primary function of lenticels in woody plants?

Accepted Answer

Allow gas exchange through the bark

Answer

Lenticels are porous areas in the bark that allow oxygen and carbon dioxide to diffuse between the atmosphere and the living cells beneath.

Question 2

During which phase of cambial activity does the cambium produce xylem cells toward the inside of the stem?

Accepted Answer

Active growth

Answer

During the active growth phase, the vascular cambium divides to produce secondary xylem (wood) toward the pith and secondary phloem toward the bark.

Question 3

What term describes the gradual death and browning of leaf tissue starting at the margins or tips?

Accepted Answer

Scorch

Answer

Scorch refers to browning of leaf margins and tips often caused by drought, salt damage, or vascular disruption preventing adequate water delivery.

Question 4

Which of the following best describes 'reaction wood' in angiosperms?

Accepted Answer

Tension wood formed on the upper side of leaning stems

Answer

Angiosperms produce tension wood on the upper side of leaning stems or branches to pull them back toward vertical, unlike gymnosperms which form compression wood on the lower side.

Question 5

What is the role of abscisic acid (ABA) in trees under drought stress?

Accepted Answer

Triggers stomatal closure to reduce water loss

Answer

ABA is produced in roots and leaves under drought stress and signals guard cells to close stomata, reducing transpiration and conserving water.

(ISA) ISA Certified Arborist Practice Test

(ISA) ISA Certified Arborist Practice Test

ISA Tree Biology and Physiology 2