The study compared the levels of green pigments in wheat leaves at different growth stages. They found that the amount of chlorophyll and carotenoid varied between the first, second, and third leaves of the wheat plants. The levels of these pigments increased as the leaves moved from the top to the bottom of the plant during the heading and mid grain filling stages. However, at the mature stage, the pigment levels did not follow a consistent pattern across the leaves but varied significantly between different wheat cultivars. The ratio of chlorophyll a to chlorophyll b also changed throughout the growth stages, increasing with leaf position initially but decreasing at the mature stage.