Plant cell wall: structure and biosynthesis

Published on January 1, 2014   58 min

Other Talks in the Series: Glycobiology

0:00
In our environment, we are surrounded by plants, our most abundant renewable resource. My name is Debra Mohnen, and in this presentation, Melani Atmodjo and I from the Complex Carbohydrate Research Center at the University of Georgia will summarize our current understanding of plant cell wall structure and synthesis.
0:23
Each year approximately 100 billion tons of carbon dioxide are fixed into biomass with roughly one-third of that produced by marine plants and microorganisms and two-thirds from land plants. In photosynthesis, plants use carbon dioxide and water taken up from the environment and energy from the sun to produce carbohydrates. The bulk of that fixed carbon ends up in the plant cell walls.
0:52
Plant cell walls are the carbohydrate-rich extracellular matrix that surrounds all plant cells. Plant cell walls and plant cells vary in shape and structure depending upon the cell type, as can be seen in these micrographs. Note the difference in shape and surface structure of the epidermis of Arabidopsis sepals, the leaf-like structure that supports petals, on the upper left versus the epidermis of petals on the upper right. Furthermore, note the intricate branch structure on the bottom left of single cell trichomes versus the elongated and pitted structure of pollen cells on the bottom right. Finally, note the round structure of suspension-cultured cells grown in liquid culture on the bottom middle versus the rigid and thicker wall structure of the large xylem cells, which make up water transporting vascular cells and cells in wood.
1:49
Plant cell walls have diverse and critical functions in the plant including providing structure to the plant and plant cells, being involved in plant growth, giving the plant flexibility, as you can see when plants sway in the wind. They provide hydration, as you may see when a seed germinates. They are a reservoir of defense and signaling molecules, and they provide cell adhesion between adjacent cells and are involved in development. If you look at the picture, what you will see is the wild-type Arabidopsis plant on the left compared to a mutant plant that is mutant in one of the plant cell wall biosynthetic enzymes, clearly showing that a knockdown in expression of a wall biosynthetic enzyme can lead to dwarfism.
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Plant cell wall: structure and biosynthesis

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