Light boosts transpiration via stomatal opening

Steps:

• Transpiration is water loss from leaves through stomata.
• Light opens stomata for photosynthesis, increasing water vapor escape.
• Both plants at 20°C, so temperature equal; only light differs.
• Light plant shows higher rate; dark plant lower or steady.

Why A is correct:

• Graph A depicts higher transpiration in light, matching light-induced stomatal opening per photosynthesis-transpiration link.

Why the others are wrong:

• B shows identical rates, ignoring light's effect on stomata.
• C shows higher rate in dark, contradicting light's role in opening stomata.
• D shows decreasing rates overall, unrelated to light difference.

Final answer: A