VIRGINIA NURSERY & LANDSCAPE
ASSOCIATION (VNLA) CERTIFIED
HORTICULTURIST EXAM STUDY GUIDE
Comprehensive Practice Questions, Verified Answers, & Detailed
Explanations
Section 1: Plant Anatomy, Physiology, & Taxonomy
Q1: Where on a plant are the majority of stomata located, and what is their primary
function?
A. On the stem; absorption of mineral nutrients
B. On the leaves; regulating gas exchange and transpiration
C. On the root hairs; anchoring the plant in soil
D. Inside the flower petals; attracting pollinators
Answer: B. On the leaves; regulating gas exchange and transpiration
Explanation: Stomata are microscopic pores located primarily on the underside of leaves. They
open and close via guard cells to regulate water loss through transpiration and allow oxygen
and carbon dioxide exchange during photosynthesis.
Q2: What plant tissue forms around the base of a stem cutting during the vegetative
rooting process?
A. Callus
B. Cambium
C. Lenticel
D. Xylem
Answer: A. Callus
Explanation: Callus is an unorganized mass of parenchymal cells that develops over a cut
stem surface as part of the plant's natural healing response. Root primordia differentiate from
callus tissue under appropriate humidity and hormonal signaling.
, Q3: What are lenticels, and what function do they serve in woody stems?
A. Small corky pores along the stem that allow gas exchange
B. Protective scales that shield terminal winter buds
C. Root nodules that house nitrogen-fixing bacteria
D. Specialized leaf veins that transport manufactured sugars
Answer: A. Small corky pores along the stem that allow gas exchange
Explanation: Lenticels are raised, corky openings in the bark of woody plants. They allow
oxygen and carbon dioxide to diffuse between internal living stem tissues (like the cambium)
and the outside atmosphere.
Q4: A houseplant bending towards light coming from a nearby window demonstrates
what physiological growth response?
A. Geotropism
B. Phototropism
C. Thigmotropism
D. Photoperiodism
Answer: B. Phototropism
Explanation: Phototropism is a directional growth response triggered by light intensity. Auxins
accumulate on the shaded side of the stem, causing those cells to elongate faster and curving
the plant toward the light source.
Q5: In botanical plant nomenclature, what does the specific epithet "rubra" indicate when
added to a genus name like Acer rubrum or Quercus rubra?
A. Evergreen foliage
B. Red color characteristics
C. Rough bark texture
D. Native to rocky soils
Answer: B. Red color characteristics
Explanation: In Latin botanical nomenclature, "rubra" or "rubrum" means red, describing red
flowers, red fruit, or vibrant red autumn foliage.
Section 2: Soil Science, Nutrition, & Fertilizer
Management
ASSOCIATION (VNLA) CERTIFIED
HORTICULTURIST EXAM STUDY GUIDE
Comprehensive Practice Questions, Verified Answers, & Detailed
Explanations
Section 1: Plant Anatomy, Physiology, & Taxonomy
Q1: Where on a plant are the majority of stomata located, and what is their primary
function?
A. On the stem; absorption of mineral nutrients
B. On the leaves; regulating gas exchange and transpiration
C. On the root hairs; anchoring the plant in soil
D. Inside the flower petals; attracting pollinators
Answer: B. On the leaves; regulating gas exchange and transpiration
Explanation: Stomata are microscopic pores located primarily on the underside of leaves. They
open and close via guard cells to regulate water loss through transpiration and allow oxygen
and carbon dioxide exchange during photosynthesis.
Q2: What plant tissue forms around the base of a stem cutting during the vegetative
rooting process?
A. Callus
B. Cambium
C. Lenticel
D. Xylem
Answer: A. Callus
Explanation: Callus is an unorganized mass of parenchymal cells that develops over a cut
stem surface as part of the plant's natural healing response. Root primordia differentiate from
callus tissue under appropriate humidity and hormonal signaling.
, Q3: What are lenticels, and what function do they serve in woody stems?
A. Small corky pores along the stem that allow gas exchange
B. Protective scales that shield terminal winter buds
C. Root nodules that house nitrogen-fixing bacteria
D. Specialized leaf veins that transport manufactured sugars
Answer: A. Small corky pores along the stem that allow gas exchange
Explanation: Lenticels are raised, corky openings in the bark of woody plants. They allow
oxygen and carbon dioxide to diffuse between internal living stem tissues (like the cambium)
and the outside atmosphere.
Q4: A houseplant bending towards light coming from a nearby window demonstrates
what physiological growth response?
A. Geotropism
B. Phototropism
C. Thigmotropism
D. Photoperiodism
Answer: B. Phototropism
Explanation: Phototropism is a directional growth response triggered by light intensity. Auxins
accumulate on the shaded side of the stem, causing those cells to elongate faster and curving
the plant toward the light source.
Q5: In botanical plant nomenclature, what does the specific epithet "rubra" indicate when
added to a genus name like Acer rubrum or Quercus rubra?
A. Evergreen foliage
B. Red color characteristics
C. Rough bark texture
D. Native to rocky soils
Answer: B. Red color characteristics
Explanation: In Latin botanical nomenclature, "rubra" or "rubrum" means red, describing red
flowers, red fruit, or vibrant red autumn foliage.
Section 2: Soil Science, Nutrition, & Fertilizer
Management
