Bio 101 Plant AnatomyEx. 2-5 Post lab discussion

Meristems

Based on location1. Apical meristem2. Lateral Meristem

Based on origin3. Primary meristems4. Secondary meristems

Root apex vs. Shoot apex

Root apex –bidirectional (root cap and towards the axis)

SUBTERMINAL

No lateral appendages

Branching initiated beyond the region of most active growth

No nodes and internodes

Fundamental Tissues

1. Parenchyma2. Collenchyma3. Sclerenchyma

Parenchyma

P-walls only; except for parenchyma found in secondary xylem

Living Intercellular spaces

Parenchyma

Collenchyma

Sclerenchyma

Retains protoplast at maturity

Yes Yes No (in general)

Secondary Walls

No No Yes

Function ? ? ?

Location ? ? ?

Collenchyma

Angular Lamellar Lacunar

Sclerenchyma

Differentiate: Sclereids Fibers

FIBERS:a. Xylary fibers—1. libriform (absent in gymno) 2. fiber-

tracheid

b. Extraxylary fibers– location?

Extra xylary fibers

Monocot: bundle sheath Climbing dicots: cortical layer;

pericyclic fibers

Sclereids

brachysclereids– phloem, cortex and bark of stems---flesh of fruits of pear

Macrosclereids– testa of seeds of legumes

Osteosclereids– seeds and leaves of dicots

Astrosclereids--leaves

Parenchyma Origins

Ground meristem Procambium Phellogen Vascular cambium

Collenchyma origins

Ground meristem Procambium

Sclerenchyma origins

Sclereid Parenchyma (sclerosis)—protoderm,

procambium, or cambium, ground merisetm

Fiber Procambium Cambium Ground meristem

Conducting Tissues

XYLEMa. Vesselsb. Tracheidsc. Fibers (libriform and fiber-tracheid)d. Parenchyma– ray parenchyma and axial

parenchyma PHLOEMa. Sieve tube or sieve cellsb. Companion cells or albuminous cellsc. Fibers (bast fibers)d. parenchyma

Vessel orTracheid?

Imperforated Tapering ends Short and drum-like Arranged end to end Overlapping

Perforation (vessels)

1. Simple2. Multiple

a. Scalariformb. Reticulatec. foraminate

Secondary wall pattern

Tracheids and vessel elements1. Protoxylem – annular or helical2. Metaxylem– scalariform; reticulate;

pitted

Annular– helical– scalariform—reticulate--pitted

Phloem

Sieve tube elements-- arranged end to end-- enucleate-- with specialized depressions at their

end wall (sieve areas)---sieve plates (end wall)

Sieve plate

a. Simpleb. Compound

Origins, Topography

Vessel Tracheid Sieve tube Companion cell Sieve cell

Advantages

Helical or annular tracheids?