Caterpillar Saliva Triggers Plant's Chemical Alarms
When a tobacco hornworm chews on a tobacco leaf, the leaf releases a chemical alarm into the air. A big-eyed bug senses the signal and flies to the leaf to feed on the hornworm's eggs.
Chemical Exchange in Plants
During the day, the sun shines on leaves, triggering guard cells to open. Guard cells allow CO2 to enter the leaf, fueling photosynthesis. While guard cells are open, 90% of the water taken up by a plant is lost. At night, guard cells close to conserve water.
The Venus Flytrap
A venus flytrap attracts insects with sweet-smelling nectar secreted by its leaves. When an insect lands to suck up the nectar, it brushes against a trigger hair. If a second trigger hair is touched within twenty seconds, the trap snaps shut. The plant then secretes digestive enzymes over the course of five to twelve days to break down its prey and absorb nutrients. The trap then reopens to discard the leftover exoskeleton and repeat the cycle.