Plants possess highly specialized tissues and cells that are adapted to facilitate both structural support and the transport of nutrients and water.
Fill in the missing terms in the statements below:
- The specialized layer of cells that forms a protective, outer barrier over the surfaces of leaves and stems is known as the _________.
- Rapidly dividing, unspecialized cells responsible for primary growth at the apex of shoots and roots are located in the _________ tissue.
In xylem tissue, the cell walls of the vessels undergo secondary thickening and waterproofing by deposition of a complex polymer. State the name of this polymer.
The diagram below shows a simplified longitudinal section of phloem tissue:
The concentration of sucrose within the lumen of the phloem sieve tube element is higher than the concentration inside the cytoplasm of Cell X.
Using your knowledge of the structures shown, explain how the abundant presence of Organelle Y inside Cell X enables the transport of sucrose into the phloem sieve tube element.
To become fully functional sieve tube elements, immature plant cells must undergo significant differentiation. State one structural modification that occurs during this differentiation process.