Angiosperm Morphology: Epidermal Papilla in Yucca Leaf
cross section: Yucca leaf
magnification: 100x
Berkshire Community College Bioscience Image Library
The leaves of Yucca show numerous structural adaptations that extend their tolerance to drought and desiccation. The epidermis is unseriate and heavily cutinized with sunken stomata evenly distributed on both adaxial and abaxial surfaces. Stomata overlay substomatal chambers and that are roofed by epidermal cells with ledge like extensions of cutin.
While the mesophyll is poorly differentiated at leaf tips the body of leaf shows one or two layers of tightly packed palisade mesophyll just beneath the epidermis.
The bulk of the leaf interior is occupied by spongy mesophyll with large open spaces. Idioblasts containing bundles of crystals of calcium oxalate are found in all parts of the mesophyll.
The vascular bundles are arranged in parallel series across the breadth of the leaf with smaller bundles towards the periphery and larger bundles in the center of the leaf.
Vascular bundles are collateral and closed with xylem of vessels and tracheids towards the adaxial surface and phloem of sieve tubes and companion cells towards the abaxial surface. Cambium is not present.
Each vascular bundle is wrapped by bundle sheath cells and supported towards adaxial and abaxial surfaces by well-developed caps of supportive sclerenchyma. Abaxial sclerenchyma caps are especially well developed in the smaller peripheral vascular bundles towards the abaxial surface.
Technical Questions:bioimagesoer@gmail.com
Angiosperm Morphology: Epidermal Papilla in Yucca Leaf
cross section: Yucca leaf
magnification: 100x
Berkshire Community College Bioscience Image Library
The leaves of Yucca show numerous structural adaptations that extend their tolerance to drought and desiccation. The epidermis is unseriate and heavily cutinized with sunken stomata evenly distributed on both adaxial and abaxial surfaces. Stomata overlay substomatal chambers and that are roofed by epidermal cells with ledge like extensions of cutin.
While the mesophyll is poorly differentiated at leaf tips the body of leaf shows one or two layers of tightly packed palisade mesophyll just beneath the epidermis.
The bulk of the leaf interior is occupied by spongy mesophyll with large open spaces. Idioblasts containing bundles of crystals of calcium oxalate are found in all parts of the mesophyll.
The vascular bundles are arranged in parallel series across the breadth of the leaf with smaller bundles towards the periphery and larger bundles in the center of the leaf.
Vascular bundles are collateral and closed with xylem of vessels and tracheids towards the adaxial surface and phloem of sieve tubes and companion cells towards the abaxial surface. Cambium is not present.
Each vascular bundle is wrapped by bundle sheath cells and supported towards adaxial and abaxial surfaces by well-developed caps of supportive sclerenchyma. Abaxial sclerenchyma caps are especially well developed in the smaller peripheral vascular bundles towards the abaxial surface.
Technical Questions:bioimagesoer@gmail.com