The Plant Cell
Name three unique parts of a plant cell
- large central vacuole
- chloroplasts
- cellulose-based cell wall
The sun has to heat/pass through a _______ volume of atmosphere during sunset compared to when the sun is shining overhead at noon.
Greater
Why do clouds insulate the Earth at night?
Clouds (water vapor) trap and re-emit heat towards Earth; water has a high heat capacity
Why does snow melt directly surrounding a tree trunk?
Heat is re-emitted from the trunk to the surroundings.
Why do plants become limp and wilted if they freeze?
Cellular dehydration & eventual rupture of the plasmalemma (plasma membrane + cytoplasm)
Ice layer shields the plants and forms a relatively warmer layer just below the ice and prevents desiccation. Small bit of biological activity occurs releasing oxygen
Why are soils with higher organic matter more resistant to temperature fluctuation?
Organic matter has a higher water holding capacity because organic matter increases the number of micropores and macropores in the soil = more space for water to fill gaps in soil and "hold on" to the soil particles
Why does the inside of your car feel warm on a very cold day when the sky is sunny and clear?
Re-radiated heat from parts of car, trapped air, convection, think: greenhouse!
If a cactus is adapted to dry weather and cold temperatures cause plant dehydration, why are most cacti unsuited to survive very cold temps?
More water stored in tissue = more ice in tissue!
What type of heat transfer is occurring when we sprinkle plants with water to prevent them from freezing?
Specific latent heat (latent heat of crystallization of water)
How might heat waves impact crop physiology/quality/plant survival?
During the daytime: Is plant temperature higher, the same, or lower than the temperature of the air? What about if the day conditions are sunny, cloudy, or rainy?
The night?
Depends!
How do Holly bushes (and berries) survive in such a wide range of temperature climates compared to fruit such as grape?
Waxy leaves, "dry" fruit
Why might air temperatures be colder under a plastic sheet we use to insulate our plant from frost?
Plastic traps humidity and damp air transfers heat more quickly than dry air thus drawing more heat out of the plant.
Does a larger day-night temperature difference create sweeter fruit?
Bonus (200 pts): Why?
Yes, usually.
How might plant roots impact soil temperature?
More tunneling = more space for air and water, bacteria & fungi recruiting!