Temperature

Yes. Topical plants can’t stand low temperatures. They may even die in temperatures above freezing.

That’s right. When ice crystals are formed in the plant cells, their membranes get cut and the cells die. Some plants can avoid this by lowering their freezing-point, using a kind of anti-freeze in the cell-sap.

It’s similar, but instead of salt plants usually use sugar.

Some plants are freezing tolerant. The water does not freeze within the cells, but in the intercellular space. The formation of ice there pulls water out of the cells. They dehydrate but will not break. Lots of our local plants go through a phase of adaptation in autumn, when then they develop a freezing tolerance for the winter – until spring, when they lose it again.