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Transpiration Lab. Transpiration. Drives movement of water through a plant Enters through the root hairs, passes through the xylem, up into the leaves, and out through stomata Transpiration = evaporation of water from the leaves
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Transpiration • Drives movement of water through a plant • Enters through the root hairs, passes through the xylem, up into the leaves, and out through stomata • Transpiration = evaporation of water from the leaves • Hydrogen bonding—weak interaction between hydrogen atom of one molecule and the oxygen atom of another molecule • You investigated factors that affect the rate of transpiration
Stomata (singular: stoma) • Hundreds of stomata in the epidermis of a leaf • Most on lower surface • Receives less solar radiation • Allow carbon dioxide to enter
Guard Cells • Guard cells surround each stoma • Regulate rate of transpiration by opening and closing • Fig. A—guard cells are turgid, stomatal opening is large • Fig B—guard cells are flaccid, stomal opening closes
Photosynthesis • 6CO2 + 6H2O C6H12O6 + 6O2carbon + water glucose + oxygen dioxide (sugar) • Leaf needs carbon dioxide and water for photosynthesis • For carbon dioxide to enter, stomata must be open • However, plant must not lose too much water • Balance between conserving water and having enough CO2 for photosynthesis
Factors That Affect the Rate of Transpiration • Light vs. dark • Humid vs. dry • Breezy vs. still air • Hot vs. warm
Calculating Water Loss • Rate of transpiration is measured as the amount of water lost/sq. meter/minute
Part 2: Stem Structure • Stems are specialized for storage, transport, and structural support
Identify each of the structures • Choices for Tissue Type: xylem, phloem, parenchyma, epidermis • Choices for Function: food transport, water transport, food storage, protection