Unit 3- Module 8 Transport of Water

Q: Describe the movement of water in plants in terms of water potential.

A: Water moves from areas of higher (less negative) water potential to lower (more negative) water potential; it follows a gradient driven by pressure and solute concentrations.

Q: What happens to the turgor potential of a leaf when it opens its stomata?

A: Turgor potential decreases because water exits the guard cells, causing them to become flaccid.

Q: What is gravity potential? What is the impact on short vs. tall plants?

A: Gravity potential is the effect of gravity on water potential; it's more significant in tall plants and minimal in short ones.

Q: What is the main driver of water movement through xylem?

A: Transpiration (evaporation of water from leaves) creates a negative pressure that pulls water upward.

Q: What percent of the water taken up by the roots may be lost to transpiration?

A: Up to 99% of the water absorbed by roots is lost via transpiration.

Q: What is an adaptation found in epiphytes to reduce transpiration?

A: Thick, waxy cuticles or trichomes reduce water loss.

Q: Translocation occurs via what tissue in plants?

A: Phloem.

Q: What component of the cell connects the mesophyll cells that produce photosynthates to the phloem for translocation to the closest sink?

A: Plasmodesmata.

Q: Where are photosynthates directed during vegetative growth?

A: To actively growing parts like roots, stems, and young leaves (the "sinks").