Excoecaria agallocha

About: Excoecaria agallocha is a research topic. Over the lifetime, 362 publications have been published within this topic receiving 5042 citations. The topic is also known as: Gewa.

Structure and regeneration status of mangrove patches along the estuarine and coastal stretches of Kerala, India

Abstract: This study presents the structural characteristics and regeneration potential of mangrove patches in the estuarine and coastal areas of Kerala, a tropical maritime state in India. Field surveys were carried out at 46 selected sites during August 2015 to May 2016. In each site, the vegetative structure and regeneration status were assessed using the quadrat method. Altogether 219 quadrates were laid out and a total of 13 true mangrove species, belonging to 5 families and 8 genera, were recorded. The total tree density and stand basal area of the study region was 1678.08/ha and 20.33 m2/ha respectively. The low basal areas indicate the reduced structural development in mangroves. Of the 13 tree species, Avicennia constitutes 56% of the total Important Value Index (IVI) and Avicennia officinalis represents 41% of the IVI in Kerala, followed by Avicennia marina (15%), Rhizophora mucronata (15%), Sonneratia alba (8%) Rhizophora apiculata (7%) and Excoecaria agallocha (7%). The diameter at breast height (DBH) in the study area revealed that 47% of the tree species came under the 1–10 cm DBH class. Total sapling and seedling density in Kerala was 2238.35 and 3232.42 individuals/ha respectively. Density of young plants (seedlings + saplings) was only 31% greater of tree density and varied from 3–63%, which indicates poor regeneration potential. The Maturity index value (MIV) and complexity index (Ic) value of mangroves were 18.30 and 109.81 respectively. However, the low Ic value (< 10) observed in seven out of ten coastal districts indicated poor structural development of mangroves in Kerala. Therefore, location-specific conservation and management measures, guided by the knowledge on spatial distribution and habitat requirements of mangrove varieties should be taken to preserve the mangrove diversity of Kerala.

Vegetation analysis of restored and natural mangrove forest in Sagar island, Sundarbans, east coast of India

Abstract: Ecological conditions were similar in the restored and natural mangrove forests, though they differed in age and elevation. The restored forest experienced total diurnal inundation, but the natural forest was not fully inundated. Thus the former was dominated by Avicennia alba, Avicennia marina and Porteresia coarctata, while the latter was dominated by Excoecaria agallocha, Ceriops decandra, Acanthus ilicifolius and Derris trifoliata. Similarity and diversity for tree and shrub layers were low and the dominance-diversity curves approached geometric series.

Nutrient Dynamics Associated with Leaching and Microbial Decomposition of Four Abundant Mangrove Species Leaf Litter of the Sundarbans, Bangladesh

Abstract: Release of nutrients and organic matter from mangrove litter during the leaching and decomposition processes play an important role in the biogeochemical cycling in mangrove ecosystems. Mass loss and nutrient dynamics associated with leaching and microbial decomposition of leaf litter of Heritiera fomes, Excoecaria agallocha, Ceriops decandra and Xylocarpus mekongensis were studied in the Sundarbans. The initial mass of H. fomes, E. agallocha, C. decandra and X. mekongensis leaf litter was significantly decreased to 11 %, 18 %, 21 % and 19 % respectively after 168 h of leaching process. Irrespectively, mass loss due to the microbial decomposition was higher for E. agallocha (97 %) followed by X. mekongensis (74 %), C. decandra (44 %) and H. fomes (42 %) after 7 months. Highest amount of N (3.29 mg/g) was released from leaf litter of C. decandra and the highest amount of P (1.69 mg/g) and K (16.36 mg/g) was released from E. agallocha. Comparatively higher amount of N (6.36 mg/g), P (2.68 mg/g) and K (16.41 mg/g) was released from the leaf litter of E. agallocha than others. Our results are useful for estimating the total flux of nutrients of mangrove forest ecosystem, especially where the studied mangrove species occur abundantly.

Rooting response in stem cuttings from five species of mangrove trees : effect of auxins and enzyme activities

Abstract: An experiment was conducted to optimise rooting in stem cuttings of the mangrove tree species Bruguiera parviflora, Cynometra iripa, Excoecaria agallocha, Heritiera fomes and Thespesia populnea. Cuttings were girdled or non-girdled and treated with the auxins indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and naphthalene-acetic acid (NAA) and amylase, IAA-oxidase, peroxidase and polyphenol oxidase activities were measured. The best rooting performance (in terms of root number) was in stem cuttings of E. agallocha followed by C. iripa and H. fomes when treated with IBA + NAA. IAA and IBA combinations were more effective in T. populnea and B. parvifolia. Variations in rooting response were markedly reflected in amylase, IAA-oxidase, peroxidase and polyphenol oxidase activities. Sharp increases in amylase and polyphenol-oxidase activities were associated with enhanced rooting in E. agallocha, C. iripa and H. fomes. On the contrary, lowered IAA-oxidase and peroxidase activities favoured rooting in T. populnea and B. parviflora. A higher number of roots occurred in pre-girdled cuttings in comparison to non-girdled cuttings.