Hydrophyteswaterplantsnaturalscience.pptx

water plants

1. HYDROPHYTES Presented by Teena Thomas II nd M.Sc. Botany

2. Hydrophytes are the aquatic plants that live freely, entirely or partially submerged in different aqueous environment. They can live in diverse habitats. They have many similarities as well as differences with the regular plants. The differences make them unique. They adapt themselves to survive in an aquatic ecosystem buy modifying their leaves, stems, and roots.

3. Classification of Hydrophytes Based on the nature of rooting and the position of foliages and flowers in relation to water, hydrophytes are classified into five groups, namely 1. Free-floating hydrophytes 2. Rooted hydrophytes with floating leaves 3. Submerged floating hydrophytes 4. Rooted submerged hydrophytes 5. Rooted emergent hydrophytes

4. Free-floating hydrophytes These are the plants which freely float on the water surface. They remain in contact with water and air. Their roots are never in contact with the soil. Their leaves are very minute. Examples : Pistia, Azolla, Salvinia, Eichornia, Lemna etc.

5. Adaptations Total absence of roots (Salvinia) or poorly developed roots (Pistia). Submerged leaves to compensate for the absence of roots (Salvinia) Absence of root cap Total absence of root hairs Stem is either long, slender and horizontal (Azolla) or short, thick, spongy and stoloniferous

6. Lemna Salvinia Pistia Eichornia Azolla Eichornia

7. 2. Rooted hydrophytes with floating leaves These are hydrophytes whose roots are fixed in mud. Their leaves and flowers float on the water surface. Leaves have long petiole so they can float on the water surface. The stem may be rhizome or stolon which remains in water. Examples : Trapa, Nelumbo, Nymphaea, Marsilia, etc.

8. Adaptations Rhizomatous stem in rooted forms with floating leaves ( Nymphaea, Nelumbo). Large and flat leaves with wax coating (Nymphaea, Nelumbo). Long and flexible petioles which are gas filled and spongy. Poorly developed cuticle (Nymphaea). Stomata is present on upper side. Mechanical tissue is absent.

9. Trapa Nelumbo Nymphaea Marsilia

10. 3. Submerged floating hydrophytes These are non-rooted hydrophytes which remains submerged in water. They are in contact only with water. They are not rooted in the soil. Their stems are long and leaves are small. Examples : Utricularia, Najas, Ceratophyllum etc.

11. Adaptations Roots are absent (Ceratophyllum). Leaves are fine (Ceratophyllum, Utricularia). Stomata are absent. Ceratophyllum Najas Utricularia

12. 4. Rooted submerged hydrophytes These are hydrophytes that completely submerged in water and rooted in soil. They can absorb nutrients from the soil. Stem may be tuberous or slender. Leaves may be small and ribbon like. Examples : Hydrilla, Vallisneria, Chara, potamogeton etc.

13. Adaptations Poorly developed roots. Flexible, long, slender, spongy, vertical stem. Small and thin leaves ( Hydrilla). Leaves are long and ribbon like (Vallisneria). Absence of cuticle and stomata in submerged leaves (Hydrilla). poorly developed vascular tissues.

14. Potamogeton Chara Hydrilla Vallisneria

15. 5. Rooted emergent hydrophytes These are the hydrophytes that grows in shallow water. Their shoot partially or completely exposed to air. Root system is completely under water and fixed in the soil Examples : Ranunculus, Sagittaria, Cyperus, Scirpus, etc.

16. Adaptations Root caps are present. Vascular elements are highly developed. stomata are present on both the sides of leaves. Mesophyll is well differentiated and contain air champers. Vascular tissue is well developed.

17. Monochoria Ranunculus Sagittaria

18. THANK YOU