Tag: permanent tissue

The parenchyma cells in the phloem tissue are known as phloem parenchyma. There are different types of phloem parenchyma cells, companion cells, albuminous and other parenchyma cells. The transfer cells are a type of companion cells. These are the cells which have folded cell wall surface. This helps to increase the transfer of the sugar in the lateral sides. They also help in scavenging the solutes which require ATP to move across the membranes. 

The sugar molecules are transported by the conducting cells in the phloem tissue in the form of sucrose. These sugar molecules are transported from the source end to the sink end. The source end is the region where the sugar is present in high concentrations. The sugar needs to be moved in the sieve elements in the source end by the process of sieve elements. Energy needs to be spent to move the sugar molecules in the form of ATP. The sugar molecules are transported through osmosis and removed from the sieve cells in the sink end by active transport. 

Sugars are synthesized as glucose and fructose, translocated as sucrose and stored as starch for long-term storage in plants. Translocation of organic nutrients from the region of source or supply to the region of utilization is mostly in the form of sucrose. Sucrose is water soluble and more efficient in energy storage as compared to the glucose and fructose as well as glucose is more reactive and hence, phloem transports sugar in the form of sucrose.

In plant transport system no heart, no blood, and no other circulatory system, but plants do need a transport system to move food, water, and minerals around. They use two different systems then xylem moves water and solutes from the roots to the leaves and phloem moves food substances from leaves to the rest of the plant, then phloem is the transporting system of food to the plants.

Xylem is the chief water and nutrients conducting tissues of the plants. These xylem tissues form the part of vascular tissues. These conduct water and nutrients from the roots to the top of the plants i.e. to the stem and the leaves. Along with acting as a conducting tissue, xylem also provides the mechanical strength to the plant parts.

Osmosis is the process of flow of fluid from higher to lower concentration through the semi-permeable membrane. The wall of xylem vessels behaves as the semi-permeable membrane so diffusion of water from one xylem vessel to another xylem vessel can be called the phenomenon of osmosis.