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I. Movement through __
a. The dissolved minerals that have been broken down by weathered rock are going to come in through the __
Inner layer of the cortex of the roots is the __
What is the endodermis
i. specialized (because cells have a Casparian strip in them) parenchyma
What is the Casparian strip?
- 1. band of cell wall material called suberin (water-proofing material)
- a. The suberin seals the spaces on the top, sides, and bottom of cells between the cell membrane and the cell wall
- b. What’s not sealed is the face and the back
What does suberin play a role in?
- a. Suberin plays a role in movement into the root because if any material that has entered the cortex but can’t enter the cell membrane, it won’t get into the vascular stele of the root= plant can’t use it
- i. Vascular stele is the center region where all the transport occurs
Why is the Casparian strip important?
1. because it forces all water and solutes to pass through the plasma membranes of endodermis cells, and thus these cells are able to exert ultimate control over the kinds and amounts of substances that enter the plant
Once through th cortex?
i. Once through the cortex and the endodermis, it can enter the vascular tissue
What are the ways in?
- sympoplastic route
- apoplastic route
- i. Where the dissolved minerals move through the root hair into the plant epidermal cell (moves into cell by going through cell membrane)
- ii. Enters epidermis by GOING THROUGH THE CELL MEMBRANE
- iii. Once in epidermal cell, it can use the plasmodesmata (connections between plants; cytoplasmic ridges) to get to the endodermis
- iv. Once in endodermis, it has to go through the cell membrane, but it’s not a problem, because that’s the way it came in
- 1. If it passes through the first, it can pass through the rest of the cell membranes
- v. Enters the stele
- i. Dissolved minerals do not enter epidermal cell, but rather travels between and enters the space between cell membrane and cell wall of the epidermal space
- ii. They continue to move through the spaces between the cell membranes and the cell wall
- iii. OH NO! THE SPACES ARE SEALED WHEN THEY GET TO THE ENDODERMIS
- 1. They can’t get through because the endodermis forces them to go through the cell membrane
- 2. Anything that can’t get through cell membrane won’t get into plant
- iv. Stuck at Casparian strip
What does the Casparian strip provide?
made of suberin and provides a restrictive layer