Hydrophytes

Ecological Adaptation in Hydrophytes
B.Sc I Year Syllabus

1. Hydrophytes
Dr. AsmitaDaspute.
Assistant Professor,
SBES College Aurangabad. India

2. Hydrophytes
Hydrophytes are the plants which live completely or partially submerged in fresh water. Such plants do not face the problem of
water shortage.
They have developed mechanisms for the removal of extra water from their cells.
Hydrophytes have broad leaves with a large number ofstomata on their upper surfaces.

4. Hydrophytes
The plants which are living in water or wet places are called hydrophytes. According to their
relation to water and air, they are subdivided into following categories:
i) Free floating hydrophytes,
ii) Rooted-floating hydrophytes,
iii) Submerged floating hydrophytes,
iv) Rooted -submerged hydrophytes,
v) Amphibious hydrophytes.

5. i. Free floating hydrophytes:
These plants float freely on the surface of water.
They remain in contact with water and air, but not with soil. Examples: Eichhornia,
Pistiaand Wolffia (smallest flowering plant).

6. ii. Rooted floating hydrophytes:
In these plants, the roots are fixed in mud, but their leaves and flowers are floating on the surface
of water. These plants are in contact with soil, water and air.
Examples: Nelumbo, Nymphaea, Potomogetonand Marsilea. Lotus seeds show highest longevity
in plant kingdom.

7. iii. Submerged
floating
hydrophytes:
These plants are completely
submerged in water and not in
contact with soil and air.
Examples: Ceratophyllum and
Utricularia. iv. Rooted-
submerged hydrophytes: These
plants are completely submerged
in water and rooted in soil and
not in contact with air.
Examples: Hydrilla, Vallisneria and
Isoetes.

8. v. Amphibious hydrophytes (Rooted
emergent hydrophytes):
These plants are adapted to both
aquatic and terrestrial modes of life.
They grow in shallow water.
Examples: Ranunculus, Typha and
Sagittaria.

9. Ecological Adoptationsin Hydrophytes:
A. Roots:
1. Due to availability of plenty of water root system is secondary importance and least significant.
2. Roots absent in Wolfia, Ceratophylum.
3. Poorly developed roots are seen in Hydrilla.
4. Submerged leaves compensate for roots in Salvania.
5. Root caps are absent in Hydrophytes.
6. Amphibious plants growing in mud will have distinct root caps.
7. Root caps are replaced by root pockets in Pistia.

10. A. Roots:

11. stem
• The stem is long, slender, spongy and flexible in submerged forms.
• In free floating forms the stem is thick, short stoloniferous and spongy; and in rooted f
loatingforms, it is a rhizome.
• Vegetative propagation is through runners, stolon, stem and root cuttings , tubers,
dormant apices and offsets.

12. leaves
• The leaves are thin, long and ribbon shaped in Vallisneria or long and linear in
Potamogetonor finely dissected in Ceratophyllum
• The floating leaves are large and flat as in Nymphaea and Nelumbo. In Eichhornia
and Trapa petioles become swollen and spongy.
• In emergent forms, the leaves show heterophylly (Submerged leaves are dissected
and aerial leaves are entire). Example: Ranunculus, Limnophilaheterophylla and
Sagittaria

14. Anatomical adaptations
• Cuticle is either completely absent or if present it is thin and poorly developed
• Single layer of epidermis is present
• Cortex is well developed with aerenchyma
• Vascular tissues are poorly developed. In emergent forms vascular elements are well developed.
• Mechanical tissues are generally absent except in some emergent forms. Pith cells are
sclerenchymatous.

15. Anatomical adaptations