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CHAPTER 20: NONVASCULAR PLANTS, moss, liverwort, hornwort - Coggle Diagram
CHAPTER 20: NONVASCULAR PLANTS
Concepts
plants
nonvascular plants
no vascular tissues or seeds
vascular cryptograms
vascular tissue but no seeds
spermatophytes
vascular tissue and seeds
adaptations
roots
freed plants from muddy habitats
vascular tissue
allowed plants to grow larger
pollen and seeds
allowed reproduction without environmental water
Characteristics of Nonvascular Plants
mosses, liverworts, and hornworts
embryophytes without vascular tissue
multicellular sporangia and gametangia
bodies composed of parenchyma
terrestrial with cuticle
many have stomata
mosses and liverworts have leafy stems
life cycle
gametophyte
larger
more prominent
haploid
sporopyte
smaller
more temporary
often inconspicuous
diploid
small and simple
Bryophyta (Mosses)
#
ubiquitous
Gametophyte Generation
Morphology
gametophores
leafy stems
grow from apical meristem
leaves
cuticle on upper surface of most leaves
usually one cell thick
stems
slender
little differentiation in layers
cortex
Water Transport
leptoids
similar to sieve cells
lack nuclei
hydroids
elongated cells
aligned above and below
conduct water and dissolved minerals
without hydroids or leptoids
water conducted along exterior of stems
through capillary action
sugar moved between parenchyma cells
through slow transport
rhizoids
trichome-like structures
anchor stem
Development
protonema
branched system of long chlorophyllous cells
perennial
produce many buds
nodules form
organize apical cell
grow up as gametophore
#
Reproduction
microgametangia
antheridia
short stalk
outer layer of sterile cells
inner mass of cells
differentiate into sperm cells
megagametangia
archegonia
vase with long neck
single egg located at base
Sporophyte Generation
never an independent, free-living plant
parts
foot
develops from basal cell
located at bottom of archegonium
small, bulbous tissue
interface with gametophore
absorbs sugars, minerals, and water
capsule
simple apical sporangium
from upper cell
outer layer of sterile cells
inner column of sterile cells
ring of sporogenous cells
produces haploid spores
seta
narrow stalk
between foot and sporangium
operculum
cap-like lid
differentiated from apex of sporangium
separates from rest of sporangium
cell breakage
peristome teeth
calyptra
layer of cells derived from neck of archegonium
covers apex of sporangium
Metabolism and Ecology
moss leaves dry out quickly when exposed to dry air
mechanisms to compensate
grow in permanently moist microhabitats
desiccation tolerance
thrive at low temperatures
grow on impervious surfaces
Hepatophyta (Liverworts)
#
alteration of heteromorphic generations
forms
leafy and resemble mosses
small, solid, ribbon-like gametophytes
Gametophyte Generation
leafy liverworts
resembles that of moss
thin leaves on slender stem
two rounded lobes with no midrib
thallose liverworts
flat and ribbon-like or heat shaped
body
thallus
air pores
gametangia
antheridiophore
stalk
dozens of antheridia grow from upper surface
rimmed with sterile cells
archegoniophore
stalk
radiating fingers
project outward and droop downward
underside has archegonia
Sporophyte Generation
basic morphology like mosses
foot, seta, calyptra-covered sporangium
#
elaters
elongate cells with spring-shaped walls
uncoil and push spores out
Anthocerotopyta (Horrnworts)
#
one chloroplast per cell
rare to find unless looking for them specifically
superficially resemble thalloid liverworts
Gametophyte Generation
thin gametophores
shapes
ribbon
heart
disk
numerous chambers
gametangium development
archegonia formed from superficial cells
do not completely surround egg
mucilage chamber turns into antheridia
Sporophyte Generation
foot embedded in gametophore tissue
no seta or discrete sporangium
meristem instead
columella and elaters
Classification of Nonvascular Plants
liverworts
division Hepatohyta
mosses
division Bryophyta
hornworts
division Anthocerotophyta
