How are heat-shock proteins thought to work?

Which of the following describes a plant's response to heat stress?

Seeds of many desert plants will not germinate until a heavy rain washes away their __________.

The triple response to mechanical stress results in __________.

In the autumn, the amount of __________ decreases, rendering the cells of the abscission layer more sensitive to __________.

The synthesis and release of abscisic acid in a plant is a response to __________.

Which of these features is/are characteristic of ethylene?

__________ appear to allow a plant cell to sense its orientation with respect to gravity.