Tag: transport in the phloem of plants

Xylem conducts water and minerals to different parts of the body which can be used for photosynthetic reaction and for several metabolic processes.
Phloem is responsible for transporting sugars, proteins and other organic molecules in plants. It is a vascular tissue in land plants primarily responsible for the distribution of sugars and nutrients manufactures in the shoot.

Phloem tissue is responsible for translocation, which is the transport of soluble organic substances, e.g., sugar. The substances travel along sieve elements, but other types of cells are also present: the companion cells, parenchyma cells, and fibres.

The food manufactured in the leaves is translocated upwards, downwards and laterally to all parts of the plant through the phloem. The phloem also conducts some other substances such as amino acids. The conducting cells of the phloem are cylindrical cells called sieve tubes, which have sieve like partitions at both ends. These partitions are called as sieve plates. 

Phloem is responsible for transport of food and minerals. Food synthesized in photosynthetic parts is translocated to non-photosynthetic parts through phloem. Food is transported in multi-directional fashion.

Xylem tissues include tracheids, vessels, fibres and parenchyma and serve in the ascent of sap/water and minerals. Phloem tissues is a composed of four elements namely, sieve elements, companion cell, phloem fibres and phloem parenchyma and serve in translocation of organic nutrients. Transfer RNA (tRNA) serve as carrier RNA and transports amino acids from cell pool to the mRNA bound to the ribosome where the protein is being synthesized. Haemoglobin molecule contains four polypeptide chains and four heme prosthetic groups. It serves as a carrier of oxygen gas. 

Phloem is a vascular tissue in land plants primarily responsible for the distribution of sugars and nutrients manufactured in the leaves of the plants by the process of photosynthesis.

Phloem tissue is responsible for translocation, which is the transport of soluble organic substances, for example, sugar. The substances travel along sieve elements, but other types of cells are also present: the companion cells, parenchyma cells, and fibers.

a) Passage cells often occur in the endodermis.

b) Stomata are cells in the epidermis of leaves. It is also called accessory or subsidiary cells.

c) Sieve tubes are related to companion cells and both are portions of plant phloem.

d) Lenticels are spongy openings in the periderm. It helps in gaseous exchange.

e) Mesophyll of a leaf comprises palisade cells that work in the absorption of light for photosynthesis.

Thus the answer is matching "A−4, B−5, C−1, D−2, E−3".

The correct option is C.

The sieve tubes are the conducting vessels in the phloem tissue. These are the long tube like cells which have perforated transverse plates. These are the cells which are responsible for the conduction of food. The sucrose is the main sugar which is the form of carbohydrate stored in the plants. The sugar is transported through the phloem vessels from the source end (leaves) to sink end (roots). 

Collenchyma tissue is elastic, extensible and have capacity to expand.