This page describes the leaf structure, highlighting its layers: the upper epidermis, which reduces water loss, and the palisade layer for photosynthesis; the spongy layer for sugar storage and gas ex...This page describes the leaf structure, highlighting its layers: the upper epidermis, which reduces water loss, and the palisade layer for photosynthesis; the spongy layer for sugar storage and gas exchange; and the lower epidermis with stomata regulated by guard cells. It also outlines the role of leaf veins, which contain xylem and phloem for water and nutrient supply, and the protective sclerenchyma cells around them, facilitating photosynthesis and food transport.