Chapter 5: Tissues and the Primary Growth of Stems

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Internal organizations of Stems: Arrangement of Primary Tissues

epidermis

outermost surface of an herbaceous stem

chemical

properties

cortex

vascular tissues

interior of the epidermis

two types

pholem

xylem

distributes

conducts

minerals

water

sugar

minerals

vascular bundles

xylem and phloem work together

waterproofing

ingested by

fungi

bacteria

animals

cutin

waxes

Basic Types of Cells and Tissues

sclerenchyma

parenchyma

collenchyma

uneven thick walls

provides plastic support

alive at maturity

lots are dead at maturity

primary walls

elastic support

secondary walls

involved in water transport

fibers

sclereids

long

dead when mature

those alive involved in storage

many dead

isodiametric

Stem Growth and Differentiation

apical meristems

subapical meristems

cells divide by

just below apical meristem

cytokinesis

mitosis

cells are

dividing

growing

External Organization of Stems

leaf axil

nodes

bud scales

internodes

phyllotaxy

auxiliary bud

rhizomes

terminal bud

tubers

important positioning of leaves

decussate

whorled

opposite

spiral

alternate

distichous

leaves per node

leaves two per node

leaves located in four rows

leaves located in two rows only

three or more leaves per node

leaves not aligned with their nearest neighbors

horizontal

only grow for short periods

example

potatoes

allow plants to spread underground

examples

fleshy horizontal stems

bamboo

canna lilies

irises

cannan lil

iris-flowers

bambo-trees-closeup-600w-250826656

extreme tip of each stem

young leaves

region between nodes

where leaves are attached

where leaf attaches

stem

protect inside organs

modified scales