How does salt and sugar affect plants growth?
What happens is that the higher concentration of salt in the soil outside of the plant cells causes water to move outside of the cells to try and equalize the concentration. Root cells die and, if bad enough, the plant will die. The damage gives the plant a burnt look- often on the leaf edges first.
The same thing happens with too much of any mineral.
Some types of plants can tolerate higher levels of salt and not be damaged. Their cells have a high concentration of salt already in them, so the water doesn't move out.
Sugar Water Effect Plants.