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This present study describes four mangrove seedlings namely Bruguiera cylindrica, B. sexangula, Ceriops tagal, and Rhizophora apiculata in response to salinity with particular emphasis to root development. The seedlings of four mangroves were grown for 5 months in 0%, 0.5%, 1.5%, 2.0% and 3.0% salt concentration. Salinity significantly decreased the growth (diameter and plant height) of all mangrove seedlings. Root developments were observed from the tap and lateral root. The number, length and diameter of both roots-typed of B. cylindrica, B. sexangula and C. tagal seedlings significantly decreased with increasing salt concentration with optimum development at 0.5% salinity. By contrast, the number, length, and diameter of tap root of R. apiculata seedlings were significantly enhanced by salt with maximal stimulation at 0.5%, and this increase was attenuated by increasing salinity. On the other hand, lateral root development of R. apiculata significantly thrived up to 1.5% salinity then decreasing with the increasing salinity. The different response of root development suggested valuable information for mangrove rehabilitation in North Sumatra and their adaption to withstand salt stress.

Mangrove forests in North Sumatera, Indonesia existed in the east coast of Sumatera Island and commonly thrived in Langkat, Deli Serdang, Batubara, Tanjung Balai, Asahan, Labuhanbatu until Serdang Bedagai. The present study describes the developing community-based mangrove management (CBMM) through eco-tourism in two locations, Lubuk Kertang (LK) of Langkat and Sei Nagalawan (SN) of Serdang Bedagai, North Sumatra, Indonesia. Mangrove ecosystem, coastal villagers and visitors, and related stakeholder were analyzed to present the potential of mangrove ecosystem, the ecological suitability, and the carrying capacity then continued with SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis. Results showed that mangrove diversity in LK consist of fifteen species which Rhizophora apiculata and Avicennia lanata dominated the area, where mangroves in SN found seven species dominated by R. apiculata and A. officinalis. Based on the suitability level of mangrove ecosystem for ecotourism development, LK and SN were categorized as suitable and conditionally suitable, respectively. The carrying capacity of mangrove ecotourism for LK and SN were 36 and 36 people/day respectively. SWOT analysis revealed that both locations of eco-tourism have a potential eco-tourism attraction, high mangrove biodiversity, possible human resources, and real people's perception on the importance of mangrove conservation, and relatively easy access. The study present suggested that mangrove ecotourism is a sustainable form of land use, to contributing the environmental protection and providing socio-economic benefits to the local people through indirect values of the natural resources.

Molecular cloning of Kandelia candel KcMS gene has previously been cloned and encoded a multifunctional triterpene synthase. In this study, the KcMS gene promoter was cloned through Genome walking, sequenced, and analyzed. A 1,358 bp genomic DNA fragment of KcMS promoter was obtained. PLACE and PlantCARE analysis of the KcMS promoter revealed that there was some regulatory elements in response to environmental signals and involved in the regulation of gene expression. Results showed that four kinds of elements are regulated by hormone binding, namely 2 MeJA-responsiveness elements (CGTCA-motif and TGACG-motif), the ABRE (TACGTG) involved in abscisic acid responsiveness, gibberellin-related GARE-motif (AAACAGA), and the TGA-element (AACGAC) as an auxin-responsive element. Several elements in the KcMS have been shown in other plants to be responsive to abiotic stress. These motifs were MBS (CAACTG), TC-rich repeats, and eight light responsive elements. The KcMS promoter was also involved in the activation of defense genes in plants such as HSE (AAAAAATTC) and four circadian control elements (CAANNNNATC). The presence of multipotential regulatory motifs suggested that KcMS may be involved in regulation of plant tolerance to several types of stresses.

Deforestation and forest degradation have been previously reported to contributing greenhouse gas emission, the primary driver of global warming. The present paper studies deforestation and reforestation trend in North Sumatra, Indonesia using land-use/land-cover change from 1990-2015. The land-use consists of three classes derived from forest land (primary and secondary dry land forest, primary and secondary swamp forest, primary and secondary mangrove forest). Non-Forest (shrub, oil palm plantation, forest plantation, settlement, barren land, swamp shrub, dry land farming, mixed dry land farming, paddy field, aquaculture, airport, transmigration, and mining), and water body (water and swamp). Results showed that from 33 regencies/city in North Sumatra, among them, 25 districts deforested, which was the highest deforestation rate in Labuhanbatu and South Labuhanbatu (2,238.08 and 1,652.55 ha/year, respectively), only one area reforested, and seven districts showed no deforestation or reforestation. During 25 years observed, the forest has been deforested 22.92%, while nonforest has been increased 11.33% of land-use. The significant increasing loss of North Sumatran forest implies conservation efforts and developing sustainable forest management.

The productivity of chili in 2014-2015 has decreased by 29,411 tons due to conversion of agricultural land. One of the efforts to increase the production of chili is by using latosol acid as a cultivation area. The low fertility of latosol land can be overcome by fertilizing. The purpose of this research was to investigate the role of duckweed and Methylobacterium on chili production which cultivated at latosol soil. The design used was Completely Randomized Design (RAL) with 6 treatments and 4 replications. The treatment consisted of P0 = control, P1 = 50 kg / ha, P2 = 100 kg / ha, P3 = 150 kg / ha, P4 = 200 kg / ha, and P5 = 250 kg / ha. Assamed data were analyzed by using variance analysis (ANOVA), Duncan's Multiple Range Test (DMRT) with confidence level 95% was used for further analysis. The results showed that fertilizer application can increase the fertility of latosol soil, percentage of chili pepper plant life, height, number of productive branches, number of flower, and amount of fruit.