Gymnosperm Stem: Periderm and Cortex in Two Year Pinus
cross section: Pinus stem
magnification: 400x
Triarch quadruple stain
Berkshire Community College Bioscience Image Library
During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins.
The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses.
Both endoderm and pericycle are inconspicuous.
Visit the BCC Bioscience Image featuring the Microscopic World of Plants. www.berkshirecc.edu/biologyimages
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Gymnosperm Stem: Periderm and Cortex in Two Year Pinus
cross section: Pinus stem
magnification: 400x
Triarch quadruple stain
Berkshire Community College Bioscience Image Library
During the first year of growth the cutinized epidermis is replaced by protective growth of cork rich periderm. The outer periderm consists of layers of cork cells, the phellem, which produces waterproofing suberin. Cork cells are dead at maturity. Deep to the phellem is a living layer of cork cambium or phellogen and beneath that, layers of cork parenchyma or phelloderm. Many cells in the periderm contain dark staining tannins.
The cortex is divided into a thin outer hypodermis of lignified sclerenchyma cells and thicker inner cortex of thin walled parenchyma cells containing chloroplasts. Large resin ducts are surrounded by secretory parenchyma that produces resins and turpentines. Some cells enlarge into dark staining tyloses.
Both endoderm and pericycle are inconspicuous.
Visit the BCC Bioscience Image featuring the Microscopic World of Plants. www.berkshirecc.edu/biologyimages
Technical Questions:bioimagesoer@gmail.com