Multi-physics modeling for ion homeostasis in multi-compartment plant cells using an energy function
Fig 4
Slice view of the space of states in the plane (,
) for the toy problem.
The level curves in the background represent the energy function G. Once the hydrogen pump has brought the system from to
, the passive evolution toward an equilibrium is only possible along the affine subspace
, which is directed by
and
(
is out of the plane). The minimum of G in
corresponds to points where the level curves of G are tangent to
. As x increases, the plane
continuously moves, dragging the equilibrium state
, which follows the thick curved trajectory. Thus, the system state always minimizes the same function G, but in a subspace that moves as x increases.