3. Salvinia spp.
HABITAT:
Still and slow moving water of
lakes, ponds, reservoirs, rice
fields etc
Grow best- nutrient rich water
Can tolerate salinity, mild
temperature, frost But not
prolonged exposed.
4. Description:
Stems: Horizontal, dichotomously branched rhizomes, protostelic and aerenchymatous
Leaves: simple, dimorphic (fertile different from sterile), aerenchymatous, at maturity in whorls of three (2
floating, 1 submerged and root-like), blades round to oblong, entire with water repellent trichomes in upper
surface
Egg beater shaped hairs – diverge into 4 branches near the top and fuse together at the tips.
The egg beater
shaped hairs
5. Roots: No true roots,
submerged leaves—function as
roots, finely dissected into several
filaments, hair-like projections
along the length.
Acts as a balances, also absorbs
nourishment from water
roots short-High nutrient
water,
Roots long - nutrient deficient
water…
Associated with N2 fixing BGA
7. Reproductive structure:
• Some filaments of leaves may develop
chains or clusters of tiny ovoid spore
bearing structures (sporocarp)
• Sporocarps: sporocarp which is
interpreted as modified sorus with
the indusium functioning as
protective wall is globose,
heterosporous, each bearing either
one megasporangium or several
microsporangia at maturity.
9. LIFE CYCLE
1. Heterosporus
2. Keep sporangia in sporocarp covered by indusium
3. Sporocarp= 1.Megasporangia 2. Microsporangia
4. Megsporangia 8 microsporocytes---------32 megaspores only
one matures and viableenlarges,fills the whole megasporangia
5. Both types develops plasmodial tapetum—solidifies– lobed body
massulae above spore
6. No annulus.. Sporocarp wall degenerate– spores germinates
meiosis
10. Gametophyte:
EDOSPOROUS
1. Male gametophyte developed by microspore bear anthredia
in 2 groups
2. Female gametophyte floats to the surface and germinates.
-photosynthetic
-form several archegonia when embryos grows…
12. Economic Importance
• Use to remove excess nutrients ,other pollutants from
water. E.g S.molesta
• Dried plants mulching, fodder
• Paper-making, biofuel, sewage treatment
• Handicrafts
• Bio-gas regeneration, bio-fertilization
• S. natans, or water moss, is used as a free floating
ornamental plant for aquariums and ponds,
• helps to purify waste or contaminated waters remove
organic material from eutrophicated water.
13. • Reaserchers at Stephan F. Austin St. Nacogdoches, Texas
Extract of giant Salvinia
inhibit growth of Human Cancer cells without destroying
nearby healthy ones.
14. ECOLOGICAL IMPACT
• Cut off lights to Aquatic plants, animal
• Reduce Oxygen content and degrade water quality—fish,etc
• Prevents natural exchange of gases between the air and body of
water.
– Causes waterway— stagnant,
– Kill any plant, insects trapped under its growth
• Problem to migratory birds fail to recognize the infested waterway
• Ideal conditions for breeding mosquitos —cause diseases
15. • Problem to Humans---
– Causes flood
– Irrigation
– Conservation of endangered species.
16. CONTROL
1. BIOLOGICAL CONTROL
A tiny weewil (Cyrtobagous salviniae) feeds on
it.
2. MECHANICAL CONTROL
Machines, By hand, Harvesting equipment.
once removed--- burnt, dried…
3. CHEMICAL CONTROL
Fluridon- use to kill the Salvinia.
4. PREVENTION
Selling, spreading, transportation etc
17. REFERENCES
1. Aquatic and Riparian Weeds of West, Joseph M. Ditomaso et
al., University of California., 2003
2. Aquatic pest control, University of California, 2001
3. The families and Genera of Vascular plants, K. Kubiizki, Vol I,
2000, Springer, UK
4. Cryptogamic Botany, Vol 2, Gilbert M. Smith, New Delhi, 1955
5. Pteridophyta,Sanjay Singh , 1st Edition, 2008