What is phototropism in plants?
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Learn how plants detect and respond to environmental stimuli and stressors.
Mastering this deck enables you to understand how plants adapt to changing environments, enhances your ability to interpret plant behavior in ecological and agricultural contexts, and informs strategies for sustainable plant management and conservation.
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| # | Front | Back | Hint |
|---|---|---|---|
| 1 | What is phototropism in plants? | Phototropism is the growth response of a plant toward or away from light, typically caused by the differential distribution of the hormone auxin, which promotes cell elongation on the shaded side. | Think of plants 'seeking' light |
| 2 | Which hormone primarily mediates positive phototropism? | Auxin, which accumulates on the shaded side of the plant, promotes cell elongation leading to bending toward the light source. | Remember 'A' for Auxin and 'A' for Attraction to light |
| 3 | How do stomata help plants respond to water stress? | Stomata regulate gas exchange and water loss; during water stress, plants often close stomata to conserve water, reducing transpiration. | Think of stomata as water-saving valves |
| 4 | What is hydrotropism? | Hydrotropism is the growth response of plant roots toward water sources, helping them access moisture in the soil. | Roots 'search' for water |
| 5 | How do plants detect water availability in their environment? | Plants sense soil moisture through changes in turgor pressure and water potential, triggering responses such as root growth toward moist areas. | Water availability influences plant 'turgor' and growth |
| 6 | What is a stress response in plants to drought conditions? | Plants respond to drought by closing stomata, synthesizing abscisic acid (ABA) to signal stress, and developing deeper roots to access water. | ABA is a key drought hormone |
| 7 | Describe how plants respond to excessive light exposure. | Plants can protect themselves from high light intensity by producing protective pigments (e.g., anthocyanins), reducing chlorophyll content, or adjusting leaf orientation to minimize damage. | Think of plants as 'sunglasses' for intense light |
| 8 | What role does the hormone abscisic acid (ABA) play in plant stress responses? | ABA is a key signaling molecule during stress conditions like drought; it promotes stomatal closure and induces stress-related gene expression to conserve water and protect the plant. | ABA = 'Anti-drying' hormone |
| 9 | How do plants adapt to waterlogged conditions? | Plants may develop aerenchyma (air spaces), form adventitious roots, or produce fermentation enzymes to survive low oxygen levels caused by waterlogging. | Think of 'aerenchyma' as internal 'air channels' |
| 10 | What is thigmotropism? | Thigmotropism is the growth response of plants to touch or physical contact, seen in climbing vines that wrap around supports. | Touch guides growth |
| 11 | How does light quality (wavelength) influence plant responses? | Plants detect different light wavelengths through photoreceptors; for example, red and far-red light influence seed germination and shade avoidance responses. | Think of photoreceptors as 'light sensors' |
| 12 | What is the shade avoidance response in plants? | When exposed to low red to far-red light ratios, plants detect shade and respond by elongating stems and leaves to outgrow competitors. | Plants 'seek the sun' when shaded |
| 13 | How do plants respond to cold stress? | Plants can increase production of antifreeze proteins, alter membrane fluidity, and accumulate solutes like sugars to prevent ice formation inside cells. | Think of 'antifreeze' proteins |
| 14 | What is the function of reactive oxygen species (ROS) in plant stress responses? | ROS are produced under stress conditions; at controlled levels, they act as signaling molecules to activate defense mechanisms, but excessive ROS can cause cellular damage. | Balance is key: ROS as 'double-edged sword' |
| 15 | Why do some plants develop thicker leaves or cuticles under stress? | Thicker leaves and cuticles reduce water loss and protect against environmental damage like UV radiation and desiccation. | Physical barriers for survival |
| 16 | What is the role of osmolytes in plant water stress tolerance? | Osmolytes like proline and glycine betaine help maintain cell turgor and protect cellular structures during dehydration. | Osmolytes act as 'cellular protectants' |
| 17 | How do plants detect and respond to light direction? | Plants use photoreceptors to detect light direction, causing differential growth that results in bending toward the light source (phototropism). | Photoreceptors 'sense' where the light is coming from |
| 18 | What adaptive feature helps desert plants conserve water? | Many desert plants have succulent tissues, extensive root systems, reduced leaf surface area, or spines instead of leaves to minimize water loss. | Desert 'survival structures' |
| 19 | How does increased CO₂ concentration affect plant water use efficiency? | Higher CO₂ levels often enhance photosynthesis and allow plants to keep stomata closed longer, reducing water loss and increasing water use efficiency. | CO₂ helps plants 'breathe better' with less water |
| 20 | What is the significance of circadian rhythms in plant responses? | Circadian rhythms regulate daily cycles in processes like opening and closing of stomata, optimizing water use, and anticipating environmental changes. | Internal 'biological clock' for plant timing |
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