mesophyll

Examples of mesophyll in the following topics:

• Leaf Structure, Function, and Adaptation

  • Below the epidermis of dicot leaves are layers of cells known as the mesophyll, or "middle leaf."
  • These are the cells of the spongy parenchyma (or spongy mesophyll).
  • Both layers of the mesophyll contain many chloroplasts.
  • (a) (top) The central mesophyll is sandwiched between an upper and lower epidermis.
  • The mesophyll has two layers: an upper palisade layer and a lower spongy layer.

• Main Structures and Summary of Photosynthesis

  • The process of photosynthesis occurs in a middle layer called the mesophyll.
  • For plants, chloroplast-containing cells exist in the mesophyll.
  • Photosynthesis takes place in the mesophyll.

• Movement of Water and Minerals in the Xylem

  • Inside the leaf at the cellular level, water on the surface of mesophyll cells saturates the cellulose microfibrils of the primary cell wall.
  • This decreases the thin film on the surface of the mesophyll cells.
  • The decrease creates a greater tension on the water in the mesophyll cells, thereby increasing the pull on the water in the xylem vessels.
  • Evaporation from the mesophyll cells produces a negative water potential gradient that causes water to move upwards from the roots through the xylem.

• Transportation of Photosynthates in the Phloem

  • Photosynthates are produced in the mesophyll cells of photosynthesizing leaves.
  • Mesophyll cells are connected by cytoplasmic channels called plasmodesmata.
  • From the mesophyll cells, the photosynthates are loaded into the phloem STEs.

• The Calvin Cycle

  • In plants, carbon dioxide (CO2) enters the leaves through stomata, where it diffuses over short distances through intercellular spaces until it reaches the mesophyll cells.
  • Once in the mesophyll cells, CO2 diffuses into the stroma of the chloroplast, the site of light-independent reactions of photosynthesis.