Angiosperm Leaf: Mesophyll Arrangement in the Hydrophyte Potamogeton
cross section: Potamogeton leaf
magnification: 400x
Berkshire Community College Bioscience Image Library
Both the upper (adaxial) and lower (abaxial) epidermis are uniseriate, lightly cutinized and contain chloroplasts. The air exposed and adaxial epidermis contains numerous stomata that open into large substomatal air spaces. The submerged and abaxial epidermis lacks stomata.
Deep to the upper epidermis are several layers of tightly packed palisade mesophyll, the chief photosynthetic tissue of the leaf. Most of the leaf interior is occupied by a deeper zone of spongy mesophyll, with large regularly arranged air spaces that extend throughout the leaf and into the stem. Spongy mesophyll gives the floating leaf buoyancy while providing abundant space for the storage of photosynthesis gases. Air chamber walls, termed diaphragms, consist of one or two layers of photosynthetic parenchyma with small perforations that allow easy movement of gases while blocking the movement of water.
Vascular bundles are centrally located with xylem toward the adaxial surface and phloem to the abaxial surface. All vascular tissues are reduced with xylem lacking in all but the largest bundles. In smaller bundles xylem is replaced by air chambers or xylem lacuna. Phloem is better developed.
All vascular tissues, including xylem, are better developed in the mid vein. Particularly noticeable is an outer bundle sheath of large parenchyma and deeper wrapping of heavy walled supportive sclerenchyma.
Technical Questions:bioimagesoer@gmail.com
Angiosperm Leaf: Mesophyll Arrangement in the Hydrophyte Potamogeton
cross section: Potamogeton leaf
magnification: 400x
Berkshire Community College Bioscience Image Library
Both the upper (adaxial) and lower (abaxial) epidermis are uniseriate, lightly cutinized and contain chloroplasts. The air exposed and adaxial epidermis contains numerous stomata that open into large substomatal air spaces. The submerged and abaxial epidermis lacks stomata.
Deep to the upper epidermis are several layers of tightly packed palisade mesophyll, the chief photosynthetic tissue of the leaf. Most of the leaf interior is occupied by a deeper zone of spongy mesophyll, with large regularly arranged air spaces that extend throughout the leaf and into the stem. Spongy mesophyll gives the floating leaf buoyancy while providing abundant space for the storage of photosynthesis gases. Air chamber walls, termed diaphragms, consist of one or two layers of photosynthetic parenchyma with small perforations that allow easy movement of gases while blocking the movement of water.
Vascular bundles are centrally located with xylem toward the adaxial surface and phloem to the abaxial surface. All vascular tissues are reduced with xylem lacking in all but the largest bundles. In smaller bundles xylem is replaced by air chambers or xylem lacuna. Phloem is better developed.
All vascular tissues, including xylem, are better developed in the mid vein. Particularly noticeable is an outer bundle sheath of large parenchyma and deeper wrapping of heavy walled supportive sclerenchyma.
Technical Questions:bioimagesoer@gmail.com