Post on 04-Jul-2015
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