Aquatic ecology and Biodiversity

Unit 10- Coastal ecosystems

10.4.2. Factors influencing mangrove environment
Salinity
Mangroves are capable of living in the salt water by reverse osmosis at the root level. Some species can exclude more than 90% of salt from the body. Another method is to secrete salt through the use of special glands on the leaves of the tree, which are among the most active salt-secreting systems known. Leaves with thick, waxy cuticles and stomata found only on their lower surfaces are examples of such modification.
Survival in the anoxic soil
The red mangroves, Rhizophora, the root system is kept above the loose, anoxic soils so as to have contact with air for respiration as against keeping the roots below the soil in other plants. In black mangroves, Avicennia spp. the presence of respiratory roots or pneumatophores extending above the anoxic mud surface of the mangrove habitats so to have gaseous exchange is a special adaptation for efficient respiration mechanisms.
Production of a propagule
Many mangrove species show vivipary (Eg. Rhizophora). The seed is germinated on the parent tree and grows by combination of photosynthesis and acquisition of nutrients from the parent. This structure, which is neither a seed nor a fruit, which usually termed a propagule, then falls to the ground and propagate and grow.
Succulent stem
Some mangrove plants are known to have succulent stem to conserve water in its body.