Do plants produce any heat? Many plants (e.g. roses, palms) can be protected from frost during the winter if shielded with an appropriate coat that can be bought in garden shops. Do plants produce any heat that can be kept inside with these "clothes"?

Cellular respiration in plants is slightly different than in other eukaryotes because the electron transport chain contains an additional enzyme called Alternative Oxidase (AOX). AOX takes some electrons out of the pathway prematurely - basically the energy is used to generate heat instead of ATP.

The exact purpose of AOX in plants is still unclear. Plants will make more AOX in response to cold, wounding, and oxidative stress. We know of at least one plant (skunk cabbage) that exploits this pathway to generate enough heat to melt snow. This link gives a pretty good overview.

!Eastern skunk cabbage melting a hole through the snow.

(AOX is dear to my heart, since my first 3 years working in a laboratory were spent studying this gene <3)