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Mangroves provide a distinctive mechanism of trapping sediment and accelerating land-building processes in tide-dominated coastal and estuarine environments. The complex hydrodynamic and salinity conditions, accumulation rates of both organic and inorganic sediments, primary surface elevation, and hydroperiod influence sediment retention mechanism within mangrove ecosystems. Abundant terrigenous sediment supply can form dynamic mud banks and the complex aerial root system of mangroves may lead to accretion of sediment by weakening the tidal velocity. Such mechanisms are often enhanced by organic flocculation. The efficiency of sediment trapping by mangroves is species specific. Adaptability and resilience of mangroves enable them to cope with the moderate to high rates of sea level rise. However, subsurface movements and deep subsidence due to autocompaction may augment the effects of relative sea level rise. Increasing population pressure and forest-based economic activities have caused global reduction of mangrove coverage challenging the sedimentation processes. Marker horizon techniques and surface elevation table (SET) tests have facilitated assessment of spatial variability in patterns of sediment accretion and surface elevation in various coastal sites of species-diverse Southeast Asia, especially coastal Malaysia and Thailand. The mangroves of the eastern coast of India have witnessed sediment retention, having an association with the seasonal rainfall regime.

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B y P G h o s h C h a u d h u r i , M. M. C h a k r a b a r t y andD. K. B h a t t a c h a r y y a *Sal (Shorearobusta),mangokemel (Mangiferaindica) and mowrah (Madhuca latifolia) are three major tree borne seed fats and regarded as potential cocoabuttersubstitutewhensuitably modified.Modificationofthesefatsby fractionation from solvent and blending of the fractions among themselves and with other suitable fatty material yielded a series of high priced confectionery fats.

The present study deals to know morphological damages of leaves of four selected plant species near roadside due to vehicular air pollution in Kolkata, India. The selected plant species are Ficus bengalensis, Ficus religiosa, Alstonia scholaris and Neolamarckia cadamba as these are very common as avenue trees. The study area was selected as per Low vehicular load (LVL) as control area, moderate vehicular load (MVL) area, high vehicular load (HVL) area and heavy vehicular load (HeVL) These three sampling stations were selected on the basis of moderate, high and heavy traffic density and continuous vehicular movement as per visualization. The control area was considered as time dependent vehicular movement due to less traffic density. The morphological damages with special reference to length (L), breadth (B) and L/B ratio and visible injuries in leaves. The visible injuries such as pigmentation, chlorosis, necrosis and burning of leaves of four selected species is documented. There was an increasing and decreasing tends in all four plant species at all three vehicular emission exposed sites (MVL, HVL and HeVL) compared to control site (LVL). In all experimental sites such as MVL, HVL and HeVL, the extra growth and reduction pattern significantly (P < 0.001, 0.01 or 0.05) observed when compared to control site (LVL) for L, B and L/B ratio. The visible injuries (in %) of leaves were also observed in increasing trends. This study is a preliminary assessment of tolerant species that already have been used in greenbelt development to protect air pollutants as well as biological monitoring to know exact load of automobile air pollution but further researches are needed in relation to biochemical and genetic damage study. It was observed that out of four selected species Ficus bengalensis, Alstonia scholaris and Neolamarckia cadamba are more tolerant species and Ficus religiosa is a less tolerant species because of these may have fighting abilities by waxy coatings, accumulation and degradation abilities to vehicular air pollution at all exposed area when compared to control area.