Temperature-sensitive mutations are useful in understanding essential life processes. A temperature-sensitive mutant will be normal at a lower (non-restrictive) temperature; when shifted to a higher (restrictive) temperature, the mutant will reveal its mutant (and potentially deleterious) phenotype. You isolate a plant with a temperature-sensitive mutation in the water-splitting complex. You grow the plant at a non-restrictive temperature, then shift it to its restrictive temperature. The outcome you would most expect to see upon shifting temperature would be

decreased NADPH production.

increased NADPH production.

no change in NADPH production.

decreased sugar production.

no change in sugar production.

increased oxygen production.

decreased NADPH production.

decreased sugar production.

Explanation:

The water-splitting complex is associated with PSII and serves as a donor of electrons to the reaction center of PSII. PSII loses its electrons upon trapping of sunlight. These electrons are passed finally to NADP reductase via electron transport chain and PSI. NADP reductase reduces NADP into NADPH. The NADPH formed during the light-dependent phase serves as reducing power in reactions of the Calvin cycle.

A mutation in the water-splitting complex would result in no electron supply to PSII and thereby, reduced production of NADPH. The reduced NADPH production would limit the supply of reducing power for the Calvin cycle and the sugar production would be decreased.