Questions and Answers
Which factor does NOT influence the growth of plants?
What term describes a plant's growth response towards a water source?
Which growth regulator is commonly used to promote fruit ripening?
Which of the following best defines geotropism?
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What is the primary role of plant promoters?
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Which structural defense mechanism does a plant employ against herbivores?
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What is thigmotropism primarily associated with?
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What defines the combined effect of plant growth regulators?
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Which of the following is a chemical defense mechanism of plants?
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Plants primarily produce growth regulators in which part?
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Study Notes
External Factors Regulating Plant Growth
- Light intensity and day length impact photosynthesis and growth patterns.
- Gravity directs root and shoot orientation, essential for nutrient and water uptake.
- Temperature influences metabolic rates and seasonal growth cycles.
Tropisms
- Tropism refers to directional growth responses of plants to external stimuli.
- Phototropism: growth towards light to enhance photosynthesis.
- Geotropism: roots grow downward in response to gravity, while shoots grow upward.
- Hydrotropism: roots grow towards areas of higher water availability.
- Thigmotropism: plants like vines respond to touch, enabling support through wrapping.
- Chemotropism: growth in response to chemical signals in the environment.
Plant Growth Regulators (PGRs)
- PGRs are chemicals that influence plant growth processes.
- They are produced in meristematic tissues, the regions of active cell division.
- The combined effect of different PGRs alters growth patterns efficiently.
- Promoters stimulate various growth processes within plants.
Applications of Plant Growth Regulators
- Ethene is used to ripen fruit, enhancing marketability and shelf life.
- Auxin is effective in weed control, disrupting the normal growth of unwanted plants.
Plant Defensive Mechanisms
- Plants must protect against water loss, overheating, infection, and herbivore attacks.
- Structural defenses: Bark acts as a barrier against pathogens, while stinging cells deter herbivores.
- Chemical defenses: Tannins render leaves unpalatable, and toxic chemicals prevent larval development.
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Description
Test your knowledge on how external factors like light and gravity influence plant growth. This quiz covers various tropisms, including phototropism and geotropism, which are essential for maximizing photosynthesis and ensuring root stability. Challenge yourself with these short answer questions!
