Temperature affects photosynthesis, transpiration, respiration, germination and flowering.
Plants are killed and damaged by frost, by water no longer being available to the plant cells effectively creating dehydration. Ice sheets on plants could grow to a thickness that reduces light availability to a level that no longer supports photosynthesis. The cells of plants shrink and if the rate of thaw is rapid, the shrunken cell walls may rupture leading to either damage or the death of the plant. There is no guarantee of recovery of plants hence patience is a virtue of most horticultural life.
To avoid hard frost damage, protect plants with coverings such as horticultural fleece to prevent frost from touching the plant directly.
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