Ducts and sieves in plant stems What are the ducts and sieves in plant bodies?

Screen. Shapes: ring, thread, trapezoid, reticulated and perforated.

The catheter is about the same length as a straw.

Catheter dead cells, as the name suggests, resemble tubes.

Sieve tubes live cells, like sieves.

Sieve tubes are living cells.

The ducts are dead cells.

The sieve tube is like a sieve (not to say you haven't seen it = =).

Sieve tubes are living cells, most of the organelles are gone, and nutrients are supplied by companion cells. This is my brain, unlike others, who either talk nonsense or, copy randomly. It is recommended that you go to the encyclopedia to take a look.

1. Duct: The pipeline for transporting water and inorganic salts in the xylem of the plant body is composed of many cylindrical cells with disappearing transverse walls connected up and down, and the liquid can flow in the tube. Roots, stems, and leaves all have duct ridges and are connected.

Water and inorganic salts and other substances dissolved in water are generally transported from the bottom up.

2. Sieve tube: The pipeline for transporting organic nutrients in the phloem of the plant body is formed by connecting many cylindrical cells on and under the hail.

There are many small pores in the transverse wall of the upper and lower adjacent cells, called ethmoid pores. Roots, stems, and leaves all have sieve tubes and are connected.

It can transport substances in both directions, and it is generally necessary to transport organic matter mainly to the sail.

Both catheters and slow-slip locust sieves belong to the conductive tissues of plants.

The duct is located in the xylem of the plant, mainly transports water and inorganic salts, and is composed of a string of highly specialized tubular dead cells, and its cell end wall is connected by perforations to make each other sensitive, in which each cell is called a duct molecule or duct node. Transporting water and inorganic salts from the bottom up.

The sieve tube is located in the phloem of higher plants, which is composed of sieve molecules, which are responsible for the long-distance transportation of photosynthetic products and a variety of organic matter in the plant body.

1. The cell properties of plant sieve tubes and ducts are different, sieve tubes are living cells of the phloem, and ducts are connected by tubular dead cells, which are located in the xylem of vascular bundles. The method and nature of transportation are also different, the sieve tube is responsible for transporting organic matter, and it is a two-way transport from the leaf to the root, the catheter is responsible for the transport of water and inorganic salts, it is one-way transport, and it is transported upwards from the roots.

2. Difference: The cell nature is different: the plant sieve tube is a living cell of the phloem, while the plant duct is different, it is connected by a string of tubular dead cells, each cell is a sieve molecule, and the upper and lower cells are through.

The method and nature of transportation are different: the plant sieve is responsible for the transport of organic matter in the phloem, which is a two-way transport from the leaf to the root. The plant duct is a one-way transport, it is responsible for the transport of water and salt in the xylem, and it is transported upwards from the roots.

The difference between sieve and catheter is mainly manifested in the cell condition, transport direction and transport route:

1.Cell condition: The duct of the plant is composed of a string of tubular dead cells, only the cells of the cell wall, and the upper and lower cells are through, and the sieve tube is the stool of the phloem of the living cells.

2.Transport direction: The plant duct is responsible for the unidirectional transport of water and salt from the root up in the xylem, while the sieve tube is responsible for the bidirectional transport of organic matter from the leaf to the root in the phloem.

3.Transportation method: Although the slag guide coarse tube and the screen tube belong to the transport tissue of the plant, the main purpose of the plant duct is to transport water, and the screen tube is mainly to transport organic matter.

1) The difference between plant sieve and catheter:

Physiological activity: Sieve tubes are made up of living cells, and ducts are made up of dead cells.

Presence of site molding: sieve tube in phloem and duct in xylem.

Physiological function: The sieve tube mainly transports organic matter, and the catheter transports water and inorganic salts slowly.

Thickness of catheter and sieve tube: Generally, the length of the sieve tube molecule is between 100 and 2000 microns, and the diameter is only 20 30 microns. The length and thickness of the duct molecules vary greatly among various plants, and the diameter of the duct molecules in most plants is generally between 20 and 30 microns.

2) The role of catheters and sives: There are two main transport channels in the plant body - conduits and sives. The ducts are dead cells, located in the xylem, that transport water and accommodable inorganic salts down from the roots.

Sieve tubes are living cells, and each sieve cell also has a companion cell, located in the hail phloem, which transports the synthesized organic matter to various parts of the plant.