Transcript group b

Aquatic macrophytes
•
•
Aquatic macrophytes are macroscopic
forms of aquatic vegetation; they include
macroscopic algae (such as Nitella and Chara),
some fern and mosses (pteridophytes) and
many flowering plants (angiosperms)
Aquatic macrophytes can be grouped into two
main groups:
1. ACQUATIC MACROPHYTES ROOTING IN
SEDIMENT
2. FREELY FLOATING MACROPHYTES
ACQUATIC MACROPHYTES
ROOTING IN SEDIMENT
•
Emergent aquatic macrophytes are rooted in the
sediment and may grow in a water depth of 1 m ( i.e.Typha
spp,Scirpus lacustris, Sagittaria sagittifolia). During the
growing season all members of this group produce aereal
leaves and flowers
• Floating-leaved aquatic macrophytes may root in a
depth up to 3 m and have floating or aereal flowers. Nymphaeae
spp., Potamogeton natans and Nuphar lutea belong to this
group.
• Submersed macrophytes complete their life cycle under
the water surface and include flowering plants as Potamogeton
pectinatus, P.perfoliatus and Myriophillum spicatum, some
moss species like Fontanilis antipyretica and algae as Chara
and Nitella
FREELY FLOATING MACROPHYTES
These macrophytes live unattached in the
water.
The
life
forms
range
from
macrophytes with floating or aerial leaves
and well developed submersed roots to very
small surface floating or submersed plants
with few or no roots ( i.e. Lemna trisulca).
Some plants in this group have aerial flowers
( Utricularia vulgaris), others complete their
life cycle under the water surface (
Ceratophyllum demersum).
Ecology
There are some environmental factors that
can influence the development of macrophytes
 ABIOTIC FACTORS
 BIOTIC FACTORS
 ANTHROPIC FACTORS
ABIOTIC FACTORS
• Sunlight:The photosynthetic rate of plants
depends on the quantity of the sunlight.
• Temperature: It determines not only the
phenology of the plants but also the coenosis
• River dynamics: the flow rate is the more
important factor for the development of a
population of macrophytes.
• The depth. It determines the quantity of light
and, consequently, the photosynthetic rate
• The transparency. It is conditioned by the flow and
influences the penetration of the sunlight.
• Substratum. The stability of the bottom is one of the
factors conditioning the development of macrophytes
• Chemical features The levels of nitrates and
phosphates are particularly important for the growth of
macrophytes but also alcalinity can influence the plant
coenosis.
• Sediment. It is the primary source of nitrogen and
phosphorous for the deep-rooted macrophytes.
• Altitude.It determines the flow, the water speed, the
water quality, the depth and, so, it can influence the
growth of macrophytes.
BIOTIC FACTORS
• Reproduction: the macrophytes can have
aerial or submersed reproductive organs
• Dispersion modality: the most common
diffusion system is by piping
• Interspecific relations. There are
competition and cooperation between
different species
• Interaction with the animal component:
there are animals that eat macrophytes.
ANTHROPIC FACTORS
•
•
Works along the river banks can alter
the macrophyte coenosis
Alteration of the chemical
composition for
1.
2.
3.
Eutrophication
Presence of pesticides
Other polluting substances
•
Mow the grass along the banks
MIS
Macrophyte Index Scheme
(Wegher e Turin, 1987)
Aquatic macrophytes can be considered good biological
indicators of
pollution because
• they are sensitive to pesticides, to organic pollution and to
eutrophication
• They are easy to identify
• They are’nt movable
This index is based on the presence/absence of some
taxa belonging to different groups of sensibility
We can define four groups ( A-B-C-D-) with a
gradient of decreasing sensibility
GROUPS OF SENSIBILITY
MACROPHYTES
GROUP A
Ranunculs sp
Callitriche hamalata
GROUP B
Ranuncul acquatilis
Ranuncul peltatus
Callitriche stagnalis
Callitriche obtusangula
Callitriche platycarpa
Chara spp.
Fontinalis antipiretica
Potamoceton lucens
Potamogeton obtusifolius
Elodea canadensis
Hippuris vulgaris
Apium nodiflorum
Rorippa nasturium-acquaticum
Groups of sensibility
Macrophytes
GROUP C
Zannichellia palustris
Sparganium spp.
Callitriche hermaphroditica
Potamogeton crispus
Potamogeton natans
Potamogeton perfoliatus
Nuphar lutea
Lemna minor
Lemna trisulca
Enteromorpha sp.
Scirpus lacustris
Myreophyllum spicatum
GROUP D
Potamogenton pectinatus
Cladophora glomerata
CLASS OF QUALITY
Proportional abundance
Q1
GROUP A Absent
CLASS V
GROUP B Absent
GROUP C Scattered emerging
GROUP D Dominant
Q2
GROUP A Absent
CLASS IV
GROUP B Absent or scattered
GROUP C Abundant
GROUP D Dominant
Q3
GROUP A Absent
CLASS III
GROUP B Common
GROP C Dominant
GROUP D Abundant
Q4
GROUP A Common
CLASS II
GROUP B Common or abundant
GROUP C Common
GROUP D Some algae
Q5
GROUP A Dominant
CLASS I
GROUP C Scattered
GROUP D Absent
This perennial pondweed
have oval floating leaves
and long, narrow,
underwater leaves. The
underwater leaves have a
broad light green central
stripe, the floating leaves
are often oppositely
arranged. The underwater
leaves are so narrow that
they appear to be stiff
leafless stalks, and the
floating leaves often have
slightly heart-shaped
bases.
• Submersed leaves: They are
alternate and stiff and can be
until 50 cm long and up to 2
mm wide.
• Floating leaves: They are
alternate and have a colour
variable from dark green to
copper-coloured; they can be
from 6 to 11 cm long and they
have a width of 6 cm. their
base is heart-shaped and the
stalk is longer than the leaf
blade.
• Persistent sheaths
(stipules): they can be from 6
to 8 cm long and are free from
the leaf base
• Stem: It is generally
unbranched and nearly
cylindrical. It is 2 mm thick.
• Flower: It consists of compact
spikes less than 5 cm long on
stalks with a length of 12 cm.
• Fruit: It is from 3.5 to 5 mm
long; the back is rounded or
faintly ridged with a beak of
0.5-1 mm.
• Root: It is fibrous
composed by rhizomes.
•
and
Propagation: It happens
through seeds come by large
winter buds. These plants
sometimes produce tubers.
Family: Potamogetaceae
Genus: Potamogeton
Name:
Potamogeton
coloratus
Lenght: 30cm-1m
Origin:
Europe,
India,
Australia, Africa
Temperature: 15°C-22°C
pH: 7.00-8.00
Hardness: 4°d GH-12°d GH
Substratum: rich
Charatteristics to recognize it:
aquatic plant that cast anchor to the
sediment and that has the leaves
completely immerse widen or
extremely lanceolate; the others that
are in surface have large leaves, oval
or lanceolate, all enough similar in
form and are transpolished. This
differentiated caratteristics from
Potamogeton Nodosus that has
opaque and hard leaves. The plant
take a red colouring. The flower is
situated out of the water, it is a short
spike and it is compact of little
flowers a bit strikings. They live only
in the water running that flows slowly.
They flowers during April-May and
also during the summer time.
Curly leaf pondweed grows
entirely underwater except for
the flower stalk which rises
above the water. Curly leaf
pondweed has distinctly wavyedged, crispy olive-green to
reddish-brown
leaves.
It
usually grows early in spring
and dies back in summer. The
leaves of flat-stem pondweed
are long and narrow with
smooth edges and the sharpedged stem is flat.
• LEAF: Alternate, all submersed, no leaf stalks.
Oblong, stiff, translucent leaves (4-10 cm long, 510 mm wide) have distinctly wavy edges with fine
teeth and 3 main veins. Sheaths (stipules) up to 1
cm long are free of the leaf base and disintegrate
with age
• STEM: branched, up to 90 cm long, somewhat
flattened.
• FLOWER: Tiny, with 4 petal-like lobes, in
spikes 1-3 cm long on stalks up to 7 cm long.
• FRUIT: Seed-like achene, 4-6
including 2-3 mm beak, back ridged.
mm
long
• ROOT: Fibrous, from slender rhizomes.
• PROPAGATION: Seeds and creeping rhizomes, over-winters as
a hard, brown, bur-like bud with crowded, small holly-like leaves.
• DISTRIBUTION: nearly worldwide
• HABITAT: shallow to deep still or flowing water, tolerant of
disturbance.
Life history of Potamogeton crispus is unusual as it flowers and
fruits in late spring and early summer, at which time it also produces
turions. The plants decay shortly after those structures develop,
leaving only fruits and turions, which survive the summer. No one
has observed any seed germination, but the turions (referred to as
dormant apices) germinate in late summer or fall, and the plants
overwinter as small plants only a few cm centimetres in size, even
under the ice in northern climates (R. L. Stuckey et al. 1978).
Growth then continues as the water begins warming in the spring.
Stems terete, ca. 1 mm thick, or the main stem stouter
on deep water forms sparingly branched at the base,
becoming freely dichotomously branched above, 3-10
dm long.
Leaves all submersed, filiform to narrowly linear, 3-12
cm long, usually 0,2-1 mm wide, 1- to 3-nerved, acute,
sometimes wider with obtuse tips early in the growing
season or on plants from running water;
Stipules adnate to the base of the leaf blade for 1-3 cm,
forming a sheath about as wide as the stem,
occasionally wider on the main stem, especially in deep
water forms.
Spikes elongate, 1-5 cm long, with 2-5 (7) unevenly
spaced floral whorls; h
Peduncles lax, filiform, to 15 cm long.
Fruits yellowish to tawny, drying brown, obliquely
obovoid, 2,7-4 mm long, rounded on the back,
apiculate due to the style beak which is usually 0,3-0,5
mm long.
Habitat Shallow to rather deep, fresh to subsaline
water of lakes, ponds, marshes, ditches, rivers and
streams; common and often abundant.