What is the Difference Between Sieve Cells and Sieve Tubes

Sieve tubes are syncytes (aggregation of cells), placed vertically one above the other forming long tubes. Sieve cells are less specialized sieve elements of phloem. Sieve tubes are much specialized sieve elements of phloem. Sieve cells are long and narrow cells with tapering end walls.

1. What is sieve cells?
2. What is the function of sieve tube cells?
3. Why are the sieve tube cells called so?
4. What is the role of sieve tubes and companion cells?
5. Where is sieve cells found?
6. Are sieve tube dead?
7. What is the function of Albuminous cells?
8. What are the function of companion cells?
9. Are companion cells living?
10. Does xylem have sieve tubes?
11. Do gymnosperms have companion cells?
12. Why sieve tubes are perforated?

What is sieve cells?

Sieve cells are a type of sieve elements that occur in the phloem of flowering plants, gymnosperms including Gnetum and Ephedra, and pteridophytes including selaginella and Pteridium. They are elongated cells with tapered ends. Therefore, they do not form a sieve tube.

What is the function of sieve tube cells?

The main functions of sieve tube members include maintaining cells and transporting necessary molecules with the help of companion cells. The sieve tube members are living cells (which do not contain a nucleus) that are responsible for transporting carbohydrates throughout the plant.

Why are the sieve tube cells called so?

Sieve cells are also associated with gymnosperms because they lack thecompanion cell and sieve member complexes that angiosperms have. ... Their narrow pores are necessary in their function in most seedless vascular plants and gymnosperms which lack sieve-tube members and only have sieve cells to transport molecules.

What is the role of sieve tubes and companion cells?

Sieve tubes members do not have ribosomes or a nucleus and thus need companion cells to help them function as transport molecules. ... It is the companion cells that helps transport carbohydrates from outside the cells into the sieve tube elements. The companion cells also allow for bidirectional flow.

Where is sieve cells found?

Sieve elements are elongated and function as the basic photosynthate-conducting cell type in the phloem of vascular plants. The walls of sieve elements contain sieve areas, circular-to-elliptical parts of the wall that are thinner.

Are sieve tube dead?

In plant anatomy, sieve tube elements, also called sieve tube members, are highly specialised type of elongated cell in the phloem tissue of flowering plants. ... Unlike the water-conducting xylem vessel elements that are dead when mature, sieve elements are living cells. They are unique in lacking a nucleus at maturity.

What is the function of Albuminous cells?

They control the physiological processes involved in phloem transport. Albuminous Cells perform a similar function for Sieve Cells. However, they are not a direct descendent of the cell which produces the Sieve Cell. Companion Cells and Albuminous Cells resemble Parenchyma cells.

What are the function of companion cells?

Reason: Companion cells move sugar and amino acids into and out of the sieve elements. In tissues such as leaf companion cells use transmembrane proteins to take up sugar like Sucrose and amino acids by active transport.

Are companion cells living?

Companion cells are living cells that are connected to the sieve-tube members of the phloem through plasmodesmata.

Does xylem have sieve tubes?

Xylem is the complex tissue of plants, responsible for transporting water and other nutrients to the plants. ... They comprise of xylem vessels, fibre and tracheids. They comprise of phloem fibres, sieve tubes, sieve cells, phloem parenchyma and companion cells.

Do gymnosperms have companion cells?

Explanation: Companion cells are the cells with abaundent plasma and nucleus present in angiosperms. But these cells are absent in gymnosperms. ... Hence gymnosperms lack companion cells.

Why sieve tubes are perforated?

The xylem vessels and phloem sieve tubes are connected end to end to transport water and food respectively to long distances in a plant. Their end plates are perforated to allow easy passage of substances from one vessels (in case of xylem) and sieve tubes (in case of phloem).