Drought stress affects the growth and productivity of wheat plants. Researchers studied how lack of water in the soil impacts gas exchange, pigment content, and other factors in durum and bread wheat. They found that drought reduces photosynthesis, stomatal conductance, and yield, while increasing leaf mass. The study showed that photosynthesis is less affected than transpiration by water stress, and the ratio of chlorophyll to carotenoids decreases under drought conditions. Overall, drought leads to lower yields and fewer wheat grains.