(That rehydration with water containing salts such as nitrate ion sometimes works when plain water (tap water or de-ionized?) doesn't implies (to me, anyway:smile
an enzyme getting turned on or off rather than simple dehydration.)
Ruth, I've tried to find out from several seed physiologists what nitrate ion is known to do re seed germination, and to date, I haven't corresponded with ONE seed person who knows the answer at a molecular level.
So in cases such as this, while there are some of us who like to understand mechanisms, I forget about it and just add some extra nitrate ion which has long been known to aid germination of many kinds of seeds.