Angiosperm Leaf: Midrib Vascular Bundles in Nymphaea
cross section: Nymphea leaf
common name: Waterlily
magnification: 100x
Berkshire Community College Bioscience Image Library
Both the upper (adaxial) and lower (abaxial) epidermis are uniseriate and contain chloroplasts. The air exposed adaxial epidermis is well cutinized and contain numerous stomata that open into large substomatal air chambers. The submerged abaxial epidermis has a very thin cuticle and lacks stomata. Dark staining slime glands are present on the abaxial surface.
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 air spaces. Large red staining branched astroscleroids are abundant throughout the mesophyll.
Vascular bundles are centrally located with collaterally arranged xylem toward the adaxial surface and phloem to the abaxial surface. Particularly noticeable is an outer bundle sheath of large parenchyma cells. All vascular tissues are highly reduced except in the mid rib area where bundles with defined phloem, proto and meta xylem, and a protoxylem lacunae can be seen. Tannin rich parenchyma cells are occasionally associated with phloem of larger bundles.
The mid rib area is supported towards the abaxial surface by a wide wedge of supportive collenchyma.
Technical Questions:bioimagesoer@gmail.com
Angiosperm Leaf: Midrib Vascular Bundles in Nymphaea
cross section: Nymphea leaf
common name: Waterlily
magnification: 100x
Berkshire Community College Bioscience Image Library
Both the upper (adaxial) and lower (abaxial) epidermis are uniseriate and contain chloroplasts. The air exposed adaxial epidermis is well cutinized and contain numerous stomata that open into large substomatal air chambers. The submerged abaxial epidermis has a very thin cuticle and lacks stomata. Dark staining slime glands are present on the abaxial surface.
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 air spaces. Large red staining branched astroscleroids are abundant throughout the mesophyll.
Vascular bundles are centrally located with collaterally arranged xylem toward the adaxial surface and phloem to the abaxial surface. Particularly noticeable is an outer bundle sheath of large parenchyma cells. All vascular tissues are highly reduced except in the mid rib area where bundles with defined phloem, proto and meta xylem, and a protoxylem lacunae can be seen. Tannin rich parenchyma cells are occasionally associated with phloem of larger bundles.
The mid rib area is supported towards the abaxial surface by a wide wedge of supportive collenchyma.
Technical Questions:bioimagesoer@gmail.com