Thursday, May 29, 2008

Parenchyma cell, oops... sclerenchyma?

There has been a fuss about the fact that parenchyma tissue can or cannot differentiate into sclereid. I should say... Yes it can. Although it is not a usual case. Let us put it this way. Meristematic cell differentiate into parenchyma cell (and other types of cell too!). Parenchyma cells, being loosely arranged and having thinner cell walls, present almost in every other tissue, have the potential to die (i. e. the protoplast disappears). Depending on where they are located they may differentiate into tissues assisting the main structure, e.g. parenchyma cells assisting the xylem tissue may die and become the fibres supporting the xylem. Certain parenchyma cells in the fruit flesh of pears, are determined to have their walls evenly thickened as the protoplast dies, to become the slereid... the ones that gives the gritty texture of pears or "buah lai"...

That's it!

The Biologist - when it comes to classification, there can be grey "individuals" which cannot be defined decisively. This would cause confusion as they can be grouped into other groups closest to their characteristics.