Question

Функции Ситовидных трубок,камбия,сосудов(дерево)

Answer 1

У ситовидных трубок транспортная функция, а точнее перенос органических веществ .
Благодаря камбию происходит рост ствола в толщину.
Сосуды(трахеи) так же переносят вещества только не органические. 

Answer 2

Functions of Sieve Tubes

Sieve tubes are specialized cells found in the phloem tissue of plants. They play a crucial role in the transport of organic nutrients, such as sugars, from the leaves to other parts of the plant. Here are some key functions of sieve tubes:

1. Transport of Organic Nutrients: Sieve tubes are responsible for the long-distance transport of organic nutrients, mainly sugars, produced during photosynthesis in the leaves. These nutrients are transported to various parts of the plant, including roots, stems, and developing fruits or seeds.

2. Sieve Element Structure: Sieve tubes are composed of sieve elements, which are elongated cells connected end-to-end to form a continuous tube. The sieve elements have specialized structures that allow for efficient nutrient transport. They contain sieve plates, which are porous structures with numerous sieve pores. These pores allow for the movement of nutrients between adjacent sieve elements.

3. Companion Cells: Each sieve element is closely associated with a companion cell. Companion cells provide metabolic support to sieve elements and help maintain their function. They supply energy and nutrients to sieve elements, as sieve elements lack many of the organelles necessary for cellular metabolism.

4. Pressure Flow Mechanism: Sieve tubes function based on the pressure flow mechanism. This mechanism involves the movement of sugars from source tissues (such as leaves) to sink tissues (such as roots or developing fruits). The high concentration of sugars in the source tissue creates a pressure gradient that drives the movement of sugars through the sieve tubes. This pressure gradient is established through active transport of sugars into the sieve tubes and the osmotic movement of water.

5. Loading and Unloading of Nutrients: Sieve tubes are involved in the loading and unloading of nutrients at source and sink tissues. At the source tissue, sugars are actively loaded into the sieve tubes, increasing the solute concentration and creating a pressure gradient. At the sink tissue, sugars are actively unloaded from the sieve tubes, reducing the solute concentration and maintaining the pressure gradient for continued nutrient transport.

Functions of Cambium

Cambium is a layer of meristematic tissue found in the stems and roots of woody plants. It is responsible for the secondary growth of the plant, which leads to an increase in girth or thickness. Here are some key functions of cambium:

1. Secondary Growth: Cambium is responsible for the production of secondary tissues, such as secondary xylem (wood) and secondary phloem. Secondary growth allows the plant to increase in girth or thickness, providing structural support and allowing for the transport of water, nutrients, and sugars.

2. Formation of Vascular Bundles: Cambium produces vascular bundles, which are composed of xylem and phloem tissues. These vascular bundles are responsible for the transport of water, minerals, and organic nutrients throughout the plant.

3. Differentiation of Xylem and Phloem: Cambium differentiates into two types of cells: xylem and phloem. Xylem cells are responsible for the transport of water and minerals from the roots to the rest of the plant. Phloem cells, including sieve tubes, are responsible for the transport of organic nutrients, mainly sugars, from the leaves to other parts of the plant.

4. Wound Healing: Cambium plays a crucial role in wound healing in woody plants. When a plant is injured, cambium cells can divide and differentiate to form new tissues, helping to close the wound and prevent the entry of pathogens.

Functions of Vascular Tissues in Trees

Vascular tissues in trees, including xylem and phloem, are essential for the transport of water, nutrients, and sugars throughout the plant. Here are some key functions of vascular tissues in trees:

1. Xylem: Xylem is responsible for the transport of water and minerals from the roots to the rest of the plant. It consists of tracheids and vessel elements, which are elongated cells that form continuous tubes. Xylem cells are dead at maturity and have thick cell walls, providing structural support to the plant. The movement of water through xylem is driven by transpiration and the cohesive properties of water molecules.

2. Phloem: Phloem is responsible for the transport of organic nutrients, mainly sugars, from the leaves to other parts of the plant. It consists of sieve tubes, companion cells, and other specialized cells. Sieve tubes, as mentioned earlier, are responsible for the long-distance transport of sugars. Companion cells provide metabolic support to sieve tubes. Phloem cells are living at maturity and rely on active transport and pressure flow mechanisms for nutrient transport.

3. Transport of Sugars: Vascular tissues, specifically phloem, play a crucial role in the transport of sugars produced during photosynthesis. Sugars are loaded into the sieve tubes at source tissues (such as leaves) and unloaded at sink tissues (such as roots or developing fruits). This transport of sugars allows for the distribution of energy and nutrients throughout the plant.

4. Structural Support: The xylem tissue in trees provides structural support to the plant. The thick cell walls of xylem cells, along with lignin deposition, contribute to the rigidity and strength of the plant's stem, allowing it to withstand the forces of gravity and environmental conditions.

In summary, sieve tubes in plants are responsible for the transport of organic nutrients, cambium is involved in secondary growth and the production of secondary tissues, and vascular tissues in trees play a crucial role in the transport of water, nutrients, and sugars throughout the plant.