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Phloem and Its Types

Q: What are the differences between the transport of material in xylem and phloem?

Transport of materials in xylem Transport of materials in phloem Xylem tissue helps in the transport of water and minerals. Phloem tissue helps in the transport of food. Water is transported upwards from roots to aerial parts of plants. Food is transported in both upward and downward directions. Transport in xylem requires physical forces such as transpiration pull. Transport of food in phloem requires energy in the form of ATP.

Q: How are simple tissues different from complex tissues, in plants?

Simple tissues are made up of only one type of cells, which look like each other. On the other hand. complex tissues are made up of more than one type of cells. Parenchyma, collenchyma and sclerenchyma are examples of simple plant tissue, whereas xylem and phloem are examples of a complex tissue. Simple tissues are protective and supportive in function. Complex tissues conduct water, minerals, and nutrients from roots and leaves to different parts of the plant.

Q: Function of companion cells is

D. Loading of sucrose into sieve elementsReason: 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. Movement of sugars in the phloem begins at the source, where sugars are loaded (actively transported) into a seive tube. Loading sets up a water potential gradient that facilitates movement of sugar.

Q: The transverse section of a plant material shows the following anatomical features:(a) The vascular bundles are conjoint, scattered and surrounded by a sclerenchymatous bundle sheaths. (b) Phloem parenchyma is absent. What will you identify it as?

The monocot stem is characterised by conjoint, collateral, and closed vascular bundles, scattered in the ground tissue containing the parenchyma. Each vascular bundle is surrounded by sclerenchymatous bundle-sheath cells. Phloem parenchyma and medullary rays are absent in monocot stems.

Q: Mention the components of the transport system in highly organized plants. State the functions of these components.

Xylem and phloem are the 2 main components of the plant's transport system. Xylem helps in the upward transport of water whereas phloem helps in the transport of food from the leaves to other plant parts.

Q: Phloem parenchyma is absent in_____________

The phloem parenchyma cells are the parenchyma cells in between the sieve tubes of the phloem, and functions primarily for food storage. They are present in monocot root, dicot root, and dicot stem. They are absent in monocot stem. Therefore, the correct answer is option B.

Q: Phloem fibres are generally absent in

Phloem Fibre: These are also called bast fibres and are made up of sclerenchyma. Phloem fibres are usually absent in primary phloem but present in secondary phloem. The phloem fibres are much elongated, unbranched and have pointed, needle-like apices.Phloem fibres of jute, flax and hemp are commercially used. The primary phloem which is first formed consists of narrow sieve tubes and is called protophloem. The later formed phloem has bigger sieve tubes and is called metaphloem.So the correct option is 'Primary phloem'.

Q: The dead cell component present in phloem is__________

Phloem is a complex permanent tissue which is generally made up of different types of cell. It is composed of phloem parenchyma, sieve cells and companion cells and fibres. Phloem fibres are represented by the dead sclerenchyma fibres that are found in between the sieve tubes. They are meant only for providing mechanical support. Phloem parenchyma, sieve cells and companion cells are living cells.Therefore, the correct answer is option A.

Q: What are complex tissues?

Those tissues that are made up of structurally different types of cells that are involved in the related functions are called complex tissues. Xylem and phloem are the complex tissues. Xylem is made up of vessels, tracheids, xylem parenchyma, and xylem fibers. Phloem is made up of sieve tubes, companion cells, phloem parenchyma, phloem fibers.

Q: What are the constituents of phloem?

Phloem is the living tissue that transports the soluble organic compounds made during photosynthesis. This transport process is called translocation. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek meaning "bark". Phloem tissue consists of conducting cells, generally called sieve elements, parenchyma cells, including both specialized companion cells or albuminous cells and unspecialized cells and supportive cells, such as fibres and sclereids.

Biology

definition

Complex permanent tissue (conducting tissue) - Phloem

This tissue helps in the transport of food throughout the plant.
The different elements of phloem include sieve tubes, companion cells and phloem parenchyma and phloem fibres.

definition

Types of phloem

The different elements of phloem include sieve tubes, companion cells, and phloem parenchyma and phloem fibres.

Sieve tubes: Transport sugars and nutrients up and down the plants in sieve cells.
Companion cells: Controls the activity of sieve tube.
Phloem parenchyma: Provides mechanical strength to the plant.
Phloem fibres: Stores compound such as starch.

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