MERISTEMS AND DIFFERENTIATION

Initial Cell division Derivative- differentiates/

matures and becomes part of a permanent tissue

• Gradually becomes different from meristematic precursor

• Gradually becomes different from neighboring cells of the same age

Initial – remains a component of the meristem (undifferentiated cell)

Mature/ differentiated cell –have completed development

a. Vary little from initial – (retain the power of cell division to a high degree e.g. parenchyma)

b. highly modified and lose most of their meristematic potentialities (e.g. sieve tube element, tracheid,fiber)

 Gradually becomes different from neighboring cells of the same age

Initials Mature cell

1.  dense protoplast*

3.  plastid in proplastid stage

vacuolated

with plastids

4. thin-walled * with thicker walls 3.  small amount of ER

Initials Mature cell

5.  isodiametric in shape* elongated cell

6.  without ergastic substances*

with ergastic substances

Cellular characteristics Initials Mature cell

7.  without intercellular spaces

9.  large centrally located nucleus

9. mitochondria with less elaborate internal membrane

with intercellular spaces nucleus along the periphery

with elaborate internal membrane