2 Obiecti a) Objective. Study of two plants and two animals found in aquatic conditions and comment SEH upon their adaptations/morphological features. ADAPTATIONS OF PLANTS AND ANIMALS TO AQUATIC CONDITIONS |. Hydrilla Comments 1 It is a submerged hydrophyte found attached to the substratum by adventitious roots in freshwater ponds. ‘The stem is soft and slender and bears thin and membranous leaves in whorls of 3-8. It limps when taken out of water showing the absence of any mechanical tissue. ‘The leaves are arranged in such a way to provide least resistance to the flow of water. They lack cuticle and stomata. ‘The whole plant is covered over by mucilage. It prevents epiphytic growth and protects the plant against the rotting effect of water.rie ™~ 402 Comprehensive Laboratory Manval jn Bi, ay, Flower. ay Water ——> a Whorts of Branch. submerged leaves Stem Roots Fig. 19.1. Hydrilla (A submerged hydrophyte). f£ Vallisneria Vv Comments 1. Itis a submerged stoloniferous flowering plant that grows in freshwater ponds. 2. The stem is reduced and the roots are mostly concerned with the function of anchorage 3. The leaves are large and ribbon shaped. They lack cuticle and stomata. 4. The leaves do not provide any resistance to the flow of water. . The whole plant is covered with mucilage. Female Female flower plant Male plant 6 ° ° ° Water 0 7 Thin oo” submerged * leaves Male flower ‘Stolon Fig. 19.2. Vallisneria (A submerged hydrophyte).pnyee ore ournuyewur. 4. Eichhornia (Water Hyacinth or Jalkumbhi) Comments 1. Itis a free floating hydrophyte that grows in ponds, lakes and water bodi water. Inflated petiole ‘Spongy stem Adventitious roots Root pocket Fig. 19.4. A part of the floating plant of Eichhornia.104 Comprehensive Laboratory Manvel ng ls “y- 2. When the level of water is low, the plant gets rooted in the soil. 3. ‘The stem is offset that grows prostrate below the surface of water. It t is spongy ang Stores 4. The leaves arise at the node in clusters. The petioles of the leaves are inflated that t heap leaves out of water. 5. The nodes also bear clusters of brown adventitious roots in water. They act as b: 5 as alancers, 6. The emerged leaves have waterproof, waxy and cuticular coating to prevent 4 wettinga 2Rwn . It has air bladder or swim bladder which maintains aves 2 sas . It possesses gills as organs of respiration for the exchange of 8: . The body is covered with water impermeable scales to pr Laboracory mers e109). yy Comprehensive §- A Freshwater Fish (Carp or Rohu) Comments 4 llow swift passage in water y Its body is compressed laterally to reduce friction and to allo hile swimming. It possesses fins that help in swimming. ses in water. event osmotic entry of water in thy body. Nostril Scales Dorsal fin Lateral line Caudal fin KEE SEO RR NY BSS a ie iy WN RKY) WHA i sn DAN NH a RD HO iN Pa OOH i wy) y DN) SN KK Y Mouth Operculum Pectoral fin Pelvicfin Anal fin Fig. 19.8. A freshwater fish.