Seed Coatings and Storage?

[Greatgardens]

Has anyone read about (or tried!) any experiments with seed coatings (either organic or inorganic in the chemical sense)? I have read that most seeds "dying" is from dehydration over time. If that is correct, then it seems like some type of coating similar to the food wax used commercially on fruits could be used to prolong seed life. Particularly if the coating also had some antibacterial properties.

My second question is more mundane. When you see "dark seeds," are they typically defective? I find normally on a ripe tomato that saving seeds will produce maybe 1-2% "dark seeds." Sometimes they look otherwise perfectly normal. I always cull them, but I also do find them frequently in commercial seed packets.

-GG