FBS 10 Lecture 2

Meristematic

cell/plant tissue that is for cell division and growth

Apical meristem

Meant for the linear growth of plant organ
found in roots and shoots (dicots)

Lateral or cambial meristem

meant for the increase in diameter of plant parts (found in stem/trunk)

Intercalary meristem 

They are involved in growth in length 
In monocots

Parenchyma

undifferentiated, unspecialized vegetative tissue (e.g. fleshy

portion of a fruit, roots, or tubers) 
Found in roots,stems, and mesophyll of leaves

Respiration

Photosynthesis

Storage

Secretion

Basic metabolic functions: parenchyma

aerenchyma

Air spaces from between

parenchyma cells (large in

stems and leaves)

Collenchyma

elongated and thickened wall (cellulose and pectin

compound); mechanical support in early growth

Lamellar

Lacunar

Angular

Types of collenchyma

Lamellar

Deposition of hemicellulose and pectin occurs

only at the cross walls separating the adjacent

cells

Angular

Deposition of hemicellulose and pectin

occurs only in the angles between the cells

Lacunar

Deposition of hemicellulose and pectin

occurs only along the border of

intercellular spaces

Sclerenchyma

thick-walled cells (lignin); fiber & sclereids (pear)-- non-living

when mature

Fibers

Occur as continuous cylinder around

stems – acting like strengthening

cables embedded in concrete, or as

a component of vascular tissues (under sclerenchyma)

Sclereid

To protect other cells

Usually in small clusters or as

solitaryVarious shapes (branched, star -

shaped, simple stone cells

Cell walls often thicker than fibers (under sclerenchyma)

Xylem

Phloem

Permanent Tissues – 2. Complex

Xylem

Transport dissolved minerals and water

absorbed by the roots

Tracheids

Vessel members
Fiber
parenchyma cells

Cells that make up xylem:

Secondary Xylem

form later

during stem and root

development

-lignified secondary walls (under xylem)

Primary Xylem

form early during

root and shoot development (under xylem) 

vascular bundles

Xylem in discrete bundles

vascular cylinder

Cells at or near the center of the root

Sieve area
sieve plate
companion cells
Parenchyma 
tracheids or fibers

Cells that make up phloem:

Sieve-tube

Main function: for transport of

carbohydrates, primarily sucrose, in the plant (underphloem)

companion cells

Connected to sieve-tube by a

plasmodesmata

Regulate metabolism of adjacent

sieve-tube member

Important in loading and

unloading the phloem

Primary phloem

-Occurs in vascular bundles near primary

xylem

(in young stem and leaves)

- Occurs in vascular cylinder

(in young roots)

Secondary phloem

Outside secondary xylem

(in older stems and roots)