For Rod: This is not scientific white paper, but written more like a magazine article that may be a little easier to understand.... little less scientific words so to speak.
Root Oxygenation http://maximumyield.com/maintaining-healthy-hydroponic-root-systems/
"Some plants require large amounts of oxygen within the root zone, particularly when growing in the protected, warm conditions provided year-round with indoor gardens. A restricted root zone is limited in how much oxygen it can hold, so it relies heavily on oxygen replenishment. This can be carried out by dissolved oxygen in the nutrient solution, or by oxygen percolation down into the root zone during irrigation."
"If roots require more oxygen than what they can get through replenishment, their function begins to slow, as does the uptake of water and nutrients."
Suffocation is clearly real bad for the plant.
Hope you enjoy the piece Rod
Cheers
J