Aponogeton Dormancy

I have a question that has bugging me for a while...and I think this is 
the place to air this "dirty laundry".  The problem is with the advice 
of what to do with the dormant Apono bulbs.  Commonly I have heard that 
you are supposed to keep them cool and dry.  I have to think with 
amusement where these bulbs are in nature and how they get to be "cool 
and dry" while they are dormant.  I think this advice was coming from 
Dutch and German gardeners who were extrapolating their experiences with 
tulip bulbs to these tropical species!  So the question I have is why 
not leave then in the substrate???  How is this going to differ to what 
happens to them when they are in the soil in a stream in Sri Lanka, or 
Madagascar??? Ok...that is all for my rant :)