Magnesium and cell energetics in plants under anoxia Available to Purchase

Stress conditions (e.g. anoxia) frequently result in a decrease of [ATP] and in an increase of [ADP] and [AMP], with a concomitant increase of [Mg²⁺] and other cations, e.g. Ca²⁺. The elevation of [Mg²⁺] is linked to the shift in the apparent equilibrium of adenylate kinase. As a result, enzymes that use Mg²⁺ as a cofactor are activated, Ca²⁺ activates calcium-dependent signalling pathways, and PP_i can serve as an alternative energy source in its active form of MgPP_i or Mg₂PP_i. Under anoxic conditions in plants, an important source of PP_i may come as a result of combined reactions of PK (pyruvate kinase) and PPDK (pyruvate, phosphate dikinase). The PP_i formed in the PPDK/PK cycle ignites glycolysis in conditions of low [ATP] by involving PP_i-dependent reactions. This saves ATP and makes metabolism under stress conditions more energy efficient.