Nitrogen deficiency affects wheat plants by reducing chlorophyll and protein levels, photosynthesis rate, and water transpiration. This study used different types of wheat to show that under low nitrogen conditions, wheat plants had lower chlorophyll and protein content, slower photosynthesis, and less water loss. The roots grew more compared to the shoots, and the internal CO2 levels were higher. Overall, nitrogen deficiency hinders chlorophyll production, leading to decreased photosynthesis and plant growth.