example of submerged plant stage
Answers
Answer:
The following points highlight the eight main stages of hydrosere in plants. The stages are:- 1. Phytoplankton Stage 2. Submerged Stage 3. Floating Stage 4. Reed Swamp Stage or Swamp5. Sedge-Meadow Stage or Marsh 6. Alder or Willow Carr Stage 7. Wood Land Stage 8. Climax Woodland.
Explanation:
Stage # 1. Phytoplankton Stage:
Planktonic stage includes minute autotrophic diatoms, phytoflagellates, cyanobacteria etc. Their dead and decomposed organic matter mixes with silt and forms soft mud at the bottom of the pond. Unicellular floating algal plants such as diatoms, members of chlorophyceae are pioneer species of a water body like lake, pond. Their spores are carried by air to the pond.
Stage # 2. Submerged Stage:
These plants root themselves in mud. Once submerged species colonize the successional changes are more rapid and are mainly autogenic as organic matter accumulates. Inorganic sediment is still entering the lake and is trapped more quickly by the net of plant roots and rhizomes growing on the pond floor.
Stage # 3. Floating Stage:
The floating plants are rooted in the mud, but some or all their leaves float on the surface of the water. The water depth will gradually decrease, allowing rooted, submerged plants, such as pondweed to grow. Water-lilies, which are rooted, but with floating leaves may also, become established.
Stage # 4. Reed Swamp Stage or Swamp:
These plants tend to have tall, flexible spear-shaped leaves. This allows the plants to cope with large fluctuations in water level; always retaining some portion of the leaves above the water for effective photosynthesis. Also called amphibious stage and plants like Typha, Sagittaria, Scripus, etc., replace the floating plants.
Stage # 5. Sedge-Meadow Stage or Marsh:
These damp areas provide a wonderful transition habitat for newly emerged from the water. At this point they are very small and extremely vulnerable to drying out. The lush wet vegetation provides an ideal hiding place. Successive decreases in water level and changes in substratum help members of Cyperaceae and Poaceae such as Carex spp. and Juncus to establish them-selves.
Stage # 6. Alder or Willow Carr Stage:
The soil is still wet, but no longer completely water-logged and anaerobic. The willow has grown up and dominates the ground. Many of the marsh plants will have been shaded out by the trees.
Stage # 7. Wood Land Stage:
First the peripheral part of the area is invaded by some shrubby plants, which can tolerate bright sunlight and water logged conditions. Plants that grow are Cornus, Cephlanthus etc. Further fall in the water table, along with mineralization and soil buildup favours the arrival of plants for next seral community.
Stage # 8. Climax Woodland:
Climax tree species include Oak, Ash and Beech. They are slow-growing, but because they are also tall and long-lived, in time, they will come to dominate an area. The particular climax tree species which eventually dominates the woodland will depend on soil type and other environmental conditions.