Leaf at work

Interactions

click the watering can: a hand tips it over the pot, water rises up the xylem, turgor returns and the stomata reopen
click a stoma: it is pinched shut for about 6 s; CO₂ stops entering there, then the guard cells swell and it reopens
click a cloud in the window: it drifts over the sun for a few seconds and the rays thin out; click the sun to clear the sky and flare the light
drag a CO₂ molecule from the air under the leaf into a stoma: if the pore is open it goes in and joins the walk to the chloroplasts