Soil compaction stress can harm cucumber plants in greenhouses by reducing their ability to photosynthesize effectively. This stress leads to lower rates of photosynthesis, stomatal conductance, and transpiration, while increasing CO2 concentration within the leaves. As a result, the plants become less efficient at converting light into energy, affecting their growth and fruit development. The decrease in photosynthesis is linked to changes in chlorophyll content and the functioning of the photosystem II reaction center in the leaves of cucumber plants under soil compaction stress.