Bio 2 lab 5 transpiration

transpiration

the loss of water vapor by plant parts(usually the leaves)

stomata

epidermal openings on the undersides of the leaves

-water vapor primarily exits through these openings

reasons for transpiration

-cools the plant

-water from roots and stems is “pulled” into the leaves

the problem with transpiration

plants are not well adapted to retain water, so they lose a significant amount of water daily

adaptations for transpiration

guard cells (2 per stomatal opening) open and close the stomata to regulate water loss

thickened cuticle (waxy covering on the leaves)

reduced leaves

modified photosynthetic pathway (C4 and CAM photosynthesis allow to keep stomata closed during the day

guard cells

-2 per stomatal opening

-open and close the stomata to regulate water loss

prepared slide of privet (Lingstrum)

observe the stomata on the lower epidermis of the leaves

potometer

can be used to measure rate of transpiration

calculated by measuring the distance traveled by water over time

the greater the rater of water uptake, the greater the transpiration rate

temperature effect on transpiration

increased-evaporation and diffusion are faster

humidity effect on transpiration

decreased

wind speed effect on transpiration

increased-moving air removes water vapor, increasing rate of diffusion of water vapor from the leaf

light intensity effect on transpiration

increased- stomata open wider to allow more CO2 into the leaf for photosynthesis

look over