Exam 37: Plant Signals and Responses to the Environment

Which of the following serves as a switching mechanism in the photoperiodic response in plants?

The plant hormone ____ trigger plant responses to environmental stresses such as cold snaps, high salinity, and drought.

At night, assuming no artificial lights, primarily ____.

The plant hormone ____ is primarily responsible for the growth of a floral stalk in rosette plants such as cabbages.

Plant hormones generally ____ concentrations to be effective, and usually have ____ on different plant tissues.

The plant hormone ____ is primarily responsible for the bending of a plant shoot toward light.

The plant hormone ____ governs senescence in plants, such as the loss of leaves in autumn by some plants.

If you want all of the orange trees in your orchard to uniformly flower and set fruit, you should spray ____ on your plants.

Thigmotropism is a growth response to ____.