The parenchymatous cell in which lignin is found
Answers
The cell walls of the vascular plants contain the polymer known as lignin. This lignin polymer is resistant to water and has its main function in providing mechanical support to the stems and leaves and rigidity to the walls of the plant. Lignin has an important role in water conduction in plant cells.
Lignin can be found in vascular plants but not in bryophytes.
Parenchyma is the most common among the ground tissue, forming the cortex and pith of the stems, root cortex and leaf mesophylls along with the fruit pulp and seed endosperms. Parenchyma cells have thin and flexible cell walls as the secondary cell wall is absent.
Parenchyma is a type of filler tissue in plants which are soft and is located in cortex, pith, pericycle and medullary rays of roots and stems.
The pith parenchyma cells have thick walls and thus higher lignin content of a different composition of the monomer than that present in xylem.
Pith cells are considered generally as homogenous parenchymatic cells and appear to have thick walls. The experimental studies have shown that higher lignification in cell corners in S1 layer and middle lamella causes intracellular checks. The brilliant colour of the walls in pith cells on adding dyes is predicted either due to higher lignification or due to the difference in lignin monomer composition.
The secondary vessel walls are highly lignified in certain plant species and there is uniform lignin distribution throughout the walls.
The chemical analysis based on experimental data has confirmed that lignin content is higher in pith than in xylem. This characteristic is important in xylem as the water column in hollow cells of xylem is under negative pressure and if there is no reinforcement by lignin the cells may collapse.
Therefore, it can be said that lignin is most commonly found in pith cells of the parenchyma.