Potassium deficiency can be greatly alleviated in the presence of sodium but the resulting sodium-rich plants are much more succulent than a high potassium plant. In some plants over 90% of the required potassium can be replaced with sodium without any reduction in growth.
http://4e.plantphys.net/article.php?ch=t&id=289 (way at the bottom)

I posted this previously, but I wanted to bring it to the forefront of all of our collectively short attention spans...

Thoughts???