Free Certified Arborist Tree Biology Questions and Answers — Questions and Answers
Question 1: Mycorrhizae refers to the beneficial relationships between the roots of trees and ________.
- fungi (Correct answer)
- mulch
- grasses
- insects
Correct answer: fungi
Mycorrhizae refers to a symbiotic relationship between the roots of trees and fungi. The fungi extend the root system's reach, enhancing the tree's ability to absorb water and nutrients, especially phosphorus. In return, the tree provides the fungi with carbohydrates produced through photosynthesis, making it a mutually beneficial association vital for tree health.
Question 2: What is a highly fertile region around growing roots?
- Substrate
- Macropore
- Periderm
- Rhizosphere (Correct answer)
Correct answer: Rhizosphere
The rhizosphere is the narrow region of soil directly surrounding plant roots, significantly influenced by root exudates and associated microorganisms. This zone is highly active biologically, with intense nutrient cycling and microbial interactions. Its rich microbial community and nutrient availability make it a highly fertile region crucial for plant growth.
Question 3: What factor in the atmosphere leads to the greenhouse effect when present in excess amounts?
- Carbon (Correct answer)
- Helium
- Nitrogen
- Oxygen
Correct answer: Carbon
Carbon, primarily in the form of carbon dioxide (CO2), is a major greenhouse gas in the atmosphere. When present in excess amounts, it traps heat radiated from Earth's surface, preventing it from escaping into space. This phenomenon leads to a warming of the planet, known as the greenhouse effect, and is a significant contributor to climate change.
Question 4: What term describes a close collection of multiple palm flowers?
- Monocot
- Petiole
- Inflorescence (Correct answer)
- Frond
Correct answer: Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem, which can be a main branch or a complex arrangement of branches. For palms, flowers are typically borne in large, often branched, structures called inflorescences. This term specifically describes the entire flowering structure containing multiple individual flowers.
Question 5: What is a turgid leaf?
- Bipinnate
- Serrated
- Dehydrated
- Fully Hydrated (Correct answer)
Correct answer: Fully Hydrated
A turgid leaf is one that is firm and rigid because its cells are fully hydrated. Water fills the plant cells, creating turgor pressure that pushes the cell membrane against the cell wall. This pressure helps maintain the leaf's shape, supports the plant, and indicates healthy water status, preventing wilting.
Question 6: Although they are made in the ____, cytokinins are crucial for the growth of the ____.
- roots, leaves
- roots, shoots (Correct answer)
- shoots, trunk
- shoots, roots
Correct answer: roots, shoots
Cytokinins are a class of plant hormones primarily synthesized in the roots. From the roots, they are transported throughout the plant, where they play a crucial role in promoting cell division, differentiation, and the growth of shoots and leaves. This hormonal action helps regulate the balance between root and shoot development.
Question 7: What is the gradual process by which a tree adapts to changes in its surroundings?
- Selection
- Hardening off
- Acclimation (Correct answer)
- Aggregation
Correct answer: Acclimation
Acclimation is the gradual physiological adjustment that an individual organism makes in response to changes in its environment. For trees, this involves non-heritable changes in their metabolism, structure, or function to better tolerate new conditions like temperature shifts, light intensity, or water availability. It allows a tree to adapt within its lifetime to new surroundings.
Question 8: When a leaf exhibits chlorosis, it is deficient in:
- Water
- Vitamin D
- Glucose
- Chlorophyll (Correct answer)
Correct answer: Chlorophyll
Chlorosis is a condition where leaves exhibit a yellowing of their tissue due to insufficient chlorophyll production. Chlorophyll is the green pigment essential for photosynthesis, and its deficiency can be caused by various factors, including nutrient deficiencies (like iron or magnesium), poor drainage, or disease. The yellowing directly indicates a lack of this vital pigment.
Question 9: Which arrangement, with a petiolule for each leaflet, places the leaflets of a compound leaf along a single stem?
- Palmate
- Pinnate (Correct answer)
- Bipalmate
- Bipinnate
Correct answer: Pinnate
In a pinnately compound leaf, the leaflets are arranged along a central stem or rachis, resembling the structure of a feather. Each individual leaflet is attached to the rachis by a small stalk called a petiolule. This arrangement distinguishes it from palmate leaves, where leaflets radiate from a single point.
Question 10: What distinguishes simple leaves from compound leaves?
- A compound leaf may have many leaflets, whereas a simple leaf just has one leaf blade. (Correct answer)
- A compound leaf has two midribs, whereas a simple leaf only has one.
- A compound leaf is oblong in shape, whereas a basic leaf is spherical.
- A simple leaf has no serrations.
Correct answer: A compound leaf may have many leaflets, whereas a simple leaf just has one leaf blade.
The fundamental difference between simple and compound leaves lies in their blade structure. A simple leaf has a single, undivided leaf blade, even if it is deeply lobed. In contrast, a compound leaf is divided into multiple distinct leaflets, each appearing as a separate small leaf, all attached to a common petiole or rachis.
Question 11: In a pine fascicle sheath, how many needles are uncommon?
- Seven
- Four (Correct answer)
- Eight
- Six
Correct answer: Four
Pine needles are typically found in fascicles (bundles) with a species-specific number of needles, commonly two, three, or five. While some species might rarely exhibit four needles, it is generally considered an uncommon or atypical number compared to the more prevalent groupings. This characteristic helps in pine species identification.
Free Certified Arborist Tree Biology Questions and Answers
Mycorrhizae refers to the beneficial relationships between the roots of trees and ________.