Plant Responses to the Environment Introduction My goal for this class is to convince you that plants are not as boring as many people think they are. They are quite dynamic creatures doing amazing things, if observed carefully. Plants live on a different time scale from that of humans and other animals. Often we have to use time lapse video images to catch their movements.

Plants respond to many environmental stimuli

Plants respond to the direction of light CB 39.0

Spectrum of light energy CB 10.6

Photosynthesis: Plants can make sugar using energy from the sun, water from the ground, and CO2 from the air. CB 10.5

Action spectrum of photosynthesis CB 10.9

Seedling germination may depend on light CB 39.18

Light quantity and quality in different environments

Seedling germination may depend on light CB 39.18

Phytochrome: a reversible receptor CB 39.20

Shade Avoidance direct light shade

Light quality is different in shade…more far-red direct light shade

Why is phytochrome reversible?

Light quality is different in shade…more far-red direct light shade

Plants respond to many environmental stimuli

Plants respond to touch CB 39.26

Plants respond to touch touched not touched CB 39.26

Another touch response CB 39.27

Bad touch: Herbivory

Bad touch: Herbivory sytemin

Bad touch: Herbivory Jasmonic acid systemin

Bad touch: Herbivory Jasmonic acid systemin Protease Inhibitors

Bad touch: Herbivory Jasmonic acid systemin I’ve got indigestion! Protease Inhibitors Protease Inhibitors Protease Inhibitors Jasmonic acid Protease Inhibitors systemin Protease Inhibitors Protease Inhibitors I’ve got indigestion!

Insect saliva can let plants know which insect is attacking plants respond to both the wound (mechanical damage) and to insect derived compounds, but they can tell the difference between a mechanical wound and an insect caused wound. - plants can sense insect saliva proteins that trigger a defense response

Plants release several volatile chemicals to signal other organisms CB 39.29

Plants release several volatile chemicals to signal other organisms Plant biology: Night moves of pregnant moths Clarence A. Ryan (29 March 2001) Nature 410, 530-531

Moth type and time Plants release different volatiles depending on who and when they are being eaten. De Moraes C. M., Mescher M. C., Tumlinson J. H. Nature 410, 577-580 (2001)

Plants release several volatile chemicals to signal other organisms Plant biology: Night moves of pregnant moths Clarence A. Ryan (29 March 2001) Nature 410, 530-531

Marine Biology… http://youtube.com/watch?v=ucMLFO6TsFM