How are roots damaged by Anoxic Environments?

Question

This would be in terms of respiration and metabollism.

Answer 1

Recall that anoxic conditions means the absence of oxygen. Using this premise, it is obvious that a plant under anoxic environs would die. The reason why roots would die in this kind of environment is that oxygen is needed in respiration and metabolism. Without this processes the plant will die.

Hope this helps...

Answer 2

without oxygen the roots

would suffer from the secondary results of the overall plant decline, which would result in death

Answer 3

Root respireation rate and metabolism are affected even before oxygen is completely depleted from the root environment.  The critical oxygen pressure (COP) is the oxygen pressure at which the respiration rate is first slowed by O2 deficiency.  The COP for a maize root tip growing in a well-stirred nutrient solution at 25 C is about .2 atmospheres, almost the concentration in ambient air.  At this oxygen partial pressure, the rate of diffution of dissolved O2 from the solution into the tissue and from cell to cell barely keeps pace with the rate of O2 utilization.  However, a root tip is metabolically very active, with respiration rates and ATP turnover comparable to those of mammalian tissue.

In older zones of the root, where cells are mature and fully vacuolated and the respiration rate is lower, the COP is often in the range of .1 to .5 atmosphere.  When O2 concentrations are below the COP, the center of the root becomes anoxic (completely lacking in oxygen) or hypoxic (partly deficient in oxygen).

The COP is lower when respiration slows down at cooler temperatures; it also depends on how bulky the organ is and how tightly the cells are packed.  Large, bulky fruits are able to remain fully aerobic because of the large intercellular spaces that readily allow gaseous diffusion.  For single cells, an O2 partial pressure as low as .01 atm can be adequate because diffusion over short distances ensures an adequate O2 supply to mitocondria.  A very low partial pressure of O2 at the mitochondrion is sufficient to maintain oxidative phosphorylation.