1. What is the main effect of auxin on cambial activity in woody plants?
A.
It stimulates the vascular cambium
B.
It permanently stops cambial activity
C.
It destroys xylem cells
D.
It prevents secondary growth
Correct Answer:
It stimulates the vascular cambium
Explanation:
Auxin promotes the activity of the vascular cambium, which contributes to secondary growth in woody plants.
2. The vascular cambium mainly produces which tissues during secondary growth?
A.
Secondary xylem and secondary phloem
B.
Root hairs and stomata
C.
Petals and sepals
D.
Pollen grains and ovules
Correct Answer:
Secondary xylem and secondary phloem
Explanation:
Auxin-supported cambial activity leads to the formation of secondary xylem toward the inside and secondary phloem toward the outside.
3. A higher auxin concentration near the stem cambium generally promotes which process?
A.
Cell division in the cambium
B.
Loss of all vascular tissues
C.
Formation of root caps only
D.
Destruction of conducting cells
Correct Answer:
Cell division in the cambium
Explanation:
Auxin stimulates cell division in the vascular cambium, helping the stem increase in thickness.
4. How does auxin help in the increase of stem girth?
A.
By stimulating secondary growth
B.
By stopping vascular tissue formation
C.
By reducing cambial cell division
D.
By preventing xylem development
Correct Answer:
By stimulating secondary growth
Explanation:
Auxin promotes cambial activity, and the resulting production of secondary vascular tissues increases stem girth.
5. Which cambial product is usually formed on the inner side of the vascular cambium?
A.
Secondary xylem
B.
Secondary phloem
C.
Epidermis
D.
Cork epidermis
Correct Answer:
Secondary xylem
Explanation:
During auxin-influenced cambial activity, the vascular cambium produces secondary xylem toward the inner side of the stem.
6. Which cambial product is usually formed on the outer side of the vascular cambium?
A.
Secondary phloem
B.
Secondary xylem
C.
Root cap
D.
Pith
Correct Answer:
Secondary phloem
Explanation:
The vascular cambium produces secondary phloem toward the outside, and auxin supports this cambial activity.
7. Auxin produced in young shoot tissues can influence cambial activity in which part of the plant?
A.
Stem
B.
Seed coat only
C.
Flower pollen only
D.
Leaf cuticle only
Correct Answer:
Stem
Explanation:
Auxin moving from young shoot tissues can stimulate the vascular cambium in the stem and support secondary growth.
8. What is likely to happen if auxin stimulation of the vascular cambium decreases?
A.
Secondary growth may decrease
B.
Stem thickening will always increase
C.
Secondary xylem formation will become unlimited
D.
Cambial cells will divide more rapidly in every case
Correct Answer:
Secondary growth may decrease
Explanation:
Reduced auxin stimulation can lower cambial activity, which may reduce the formation of secondary xylem and phloem.
9. Auxin is important in cambial activity because it helps regulate the formation of which type of growth?
A.
Secondary growth
B.
Only seed germination
C.
Only flower opening
D.
Only leaf fall
Correct Answer:
Secondary growth
Explanation:
Auxin regulates vascular cambial activity, which is responsible for secondary growth and the increase in stem thickness.
10. Which tissue is directly responsible for the cambial activity stimulated by auxin?
A.
Vascular cambium
B.
Epidermis
C.
Parenchyma of the leaf mesophyll only
D.
Root cap
Correct Answer:
Vascular cambium
Explanation:
The vascular cambium is a lateral meristem whose cell division, supported by auxin, produces secondary vascular tissues.
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