Vegetative propagation of some selected mangrove species from Negombo estuary, Sri Lanka

Abstract

Mangrove forests are degraded and threatened worldwide, due to anthropogenic events. Mass production of planting material and successful germination of seeds are essential processes in rehabilitating these degraded mangrove forests. The present work was carried out to determine the efficacy of using propagule cuttings in mass production of plant materials and to determine the potential of using non mangrove soils to establish propagule cuttings for ornamental purposes. In addition air layering and stem cutting techniques were also tested for the mangrove propagation. Propagation of Rhizophora apiculata, by propagule cuttings, treated with root promoting hormones is feasible and it was possible to produce three saplings from one propagule. Indole Butyric Acid (IBA) (1000 ppm) was the best hormone concentration for inducing roots and IBA (1500 ppm) was the best for inducing shoots from propagule cuttings of R. apiculata. Air layering and stem cutting were performed with Avicennia marina and R. apiculata but none of the species was able to generate roots and therefore these vegetative propagation methods cannot be used for mass propagation of these mangrove species. Optimum growth medium and period of nursery care for mangrove saplings of R. apiculata, Ceriops tagal and Bruguiera sexangula were studied and the results revealed that best growth performance was in mangrove soils, i.e. 4.15 cm/ 4weeks for R. apiculata, 3.75 cm/ 4weeks for B. sexangula and 0.56 cm/ 4 weeks for C. tagal, while mangrove soils mixed with sand produced the second best growth for C. tagal and B. sexangula. Seedlings grown on terrestrial soils showed the lowest growth rate for all three mangrove species. However, no significant difference (P < 0.05) exists in growth rates of mangrove seedlings when grown in different growth media, indicating they can be grown with terrestrial soil for ornamental purposes. Potting media consisted only of mangrove soils as well as mangrove soils (1): sand (1), terrestrial soil alone and mangrove soil (1): terrestrial soil (1) can be used as nursery growth media for R. apiculata and C. tagal.

Response of mangrove plant species to a saline gradient: Implications for ecological restoration

“…R. apiculata, however, had its best growth at a salinity of 0 PSU. Seedlings of R. apiculata have been reported to perform well in mangrove and nonmangrove soil mixtures (with low salinity) under nursery conditions (Silva & Amarasinghe 2010), suggesting that the species has an ability to thrive in soils of very low salinity. Besides, the accumulation of high amounts of sodium and chloride ions in plant tissues, and energy-consuming production of organic osmolytes such as proline and betaine to maintain the osmotic balance (required for plant water uptake), may result in lower seedling growth (Aziz & Khan 2001a;Singh & Sharma 2017).…”

Konservasi Mangrove Berbasis TRM (Tanam Rawat Monitoring) untuk Menjaga Sumberdaya Laut di Cengkrong, Trenggalek

“…Masyarakat setempat memanfaatkan Rhizophora mucronata sebagai pematang tambak, sehingga pohonnya jarang untuk ditebang. Hal tersebut berbeda dengan spesies Bruguiera gymnorrhiza yang memiliki jumlah INP sangat rendah pada zonasi A, disebabkan propagul sering terbawa aliran air ketika pasang, sehingga propagul tidak menetap pada substrat yang ada di sekitar pohon, hal tersebut akan berpengaruh pada pertumbuhan calon individu baru (De Silva et al, 2010;Noor et al, 2012). (Noor et al, 2012).…”

Spatial distribution and dynamics of selected mangrove forests on the east and west coasts of Sri Lanka

“…The spatial distribution and vegetation structure of mangroves in different localities are influenced by many factors such as temperature, precipitation, freshwater runoff, erosion/sedimentation rates, aridity, salinity, nutrient inputs, and ocean circulation pattern (Gilman et al 2008;Osland et al 2017;De Silva and Amarasinghe, 2010;Record et al 2013;de Silva and Amarasinghe 2021a). These factors may largely determine the floristic and faunistic composition and the community structure of the mangrove ecosystem (Cintron et al 1985;Cintron and Novelli 1984).…”