Effect of Planting Media Modification on Seed Growth and Development of Three Mangroves Species from Jakarta and Kebumen, Indonesia

The rehabilitation of mangroves depends on the availability of high-quality, sufficiently prominent seeds. Currently, a lot of mangrove nursery activities continue to employ traditional techniques, which results in low-quality and slowly growing seedlings. The mangroves of Jakarta were selected because they represent a heavily polluted mangrove ecosystem on Java's northern coast, whereas the mangroves in Kebumen, on Java's southern coast, are in the opposite situation. This study proposed to find an approach to supply Indonesia's mangrove restoration projects with adequate seeds. An experimental approach with a complete randomized design and a factorial pattern was used. The variables tested were planting media and three kinds of mangroves: Rhizophora mucronata, Ceriops tagal, and Bruguiera gymnorrhiza. Mangroves from Jakarta are treated with mud, soil media, or a mix of them. A mixture of mud, husk, and husk charcoal is used for six treatments planting media for mangroves from Kebumen. The mangrove seedlings' growth, biomass, and chlorophyll content are the dependent variables. ANOVA was used to evaluate the data with a 95% confidence level, and Duncan's comparison of means test followed. The growth of mangrove seedlings was discovered to be impacted by media type, while the chlorophyll content, dry biomass of roots, stems, and leaves were not affected by this factor. Three species of mangroves differ regarding growth rate, biomass of roots, stems, and leaves, and chlorophyll content. In order to support Indonesia's efforts to rehabilitate mangroves, this research can offer understanding regarding how to select and employ the best media to effectively produce high-quality seeds.


Introduction
The goods and services that mangrove ecosystems offer serve as essential for both the environment and people (Getzner and Islam, 2020).Mangroves provide a variety of resources and commodities, such as wood, fuel, fibre, food, medicine, colors, and others (Lin et al., 2022;Ramesh et al., 2022).Mangrove habitats provide a wide variety of ecological and environmental services, such as supporting and regulating roles.Additionally, mangroves provide cultural services or human culture (Clough, 2013).Serving as a nursery, spawning site, and feeding ground for marine and estuarine biota, which includes biota that has important economic value, are instances ecological supporting services (Ardli et al., 2015).
The mangrove environment is an ecological asset that offers numerous benefits to the people who live in surrounding areas of the ecosystem (Anu et al., 2024).In addition to their ecological roles, mangroves are one of the primary marine fisheries producers (Tomlinson, 1994;Giesen et al., 2007;Ardli et al., 2015).Mangroves contribute to the carbon, nitrogen, and sulphur cycles by producing nutrients that may enrich marine environments (Yuwono et al., 2007).Mangroves are able to sustain fish, crustacean, shellfish, and other biota populations due to their high primary production (Abrogueña et al., 2012).In addition, a number of animal species find food and breeding grounds in mangroves (Anneboina and Kumar, 2017).
Over the past four decades, mangrove ecosystem services and functions reduced due to with damage and shrinkage of mangrove areas.This causes a number of issues, such as diminished fisheries productivity, decreased mangrove diversity, habitat and nursery area loss, decreased mangrove and water productivity, pollution, acidification of the soil, and intrusion of seawater (Ardli and Wolff, 2009;Koswara et al., 2017;Ardli et al., 2022).There are 3.3 million hectares of mangrove forests in Indonesia (Nurbaya, 2020), with approximately 182,091 hectares lost during the 2009-2019 period (Arifanti et al., 2021), that require immediate rehabilitation.The availability of seeds that are high-quality and sufficient in quantity for rehabilitation projects is one challenge that needs to be resolved.Almost all of Indonesia's mangrove habitats are dominated by the genus Rhizophora.In damaged areas, mangrove restoration actions frequently use various species of this genus derived from various research.The reasoning for which is since Rhizophora seedlings have a wide tolerance range for salinity (Basyuni et al., 2018), easy growing at various substrates and soil (Amaliyah et al., 2018), found on the coast of southern Java such as Segara Anakan (Nordhaus et al., 2019).Ceriops is often found in quite dominant numbers in the coastal areas of southern Java (Koswara et al., 2017;Nordhaus et al., 2019;Rahman et al., 2019).The availability of sufficient amounts of high-quality mangrove seeds can provide difficulties to mangrove rehabilitation activities.In addition to it, there is not a simple, effective way for mangrove seeding.As a result, studies on mangrove seeding techniques and media adjustments are required.The aim of this study is to find out the planting media that provides optimal influence on the growth of Bruguiera gymnorrhiza, Rhizophora mucronata and Ceriops tagal seedlings, and to find out the best seeding methods for Rhizophora, Bruguiera and Ceriops.
Variables observed consist of dependent and independent variables.The independent variable is the planting medium which consist of 6 and 3 levels of treatment, and three species of mangroves.While, the dependent variables are the biomass of root, stem, leaves, and also chlorophyll content of mangrove leaves.The primary parameter is the high of seeding, the biomass which consist of dry weight of root, stem, leaves, and chlorophyll content of mangrove leaves.The secondary parameter are water content, carbon content, pH, and N, P, K content in the media.Parameters were measured every week up to eight weeks.
Biomass measurement was done by destructive harvesting.Following harvesting, the seedlings were cleaned and separated into sections based on the leaf, branch, stem, and root sections.These were dried for 72 h at 70°C until a consistent weight was reached.With an accuracy of ±0.003g, the oven-dry mass was measured to the milligram using the standard laboratory scale (Bebre et al., 2021).Organic solvents (80% acetone) are used in destructive procedures for the measurement of chlorophyll.To inhibit the activity of chorophllase, 0.25g of leaf sample was ground in 2ml of 80% acetone with sand (0.1% or 0.1 CaCO3).After the samples were filtered through filter papers to a final volume of 25 ml, they were put into a spectrophotometer to measure absorbency (A663 and A646).The absorbency was determined using equations 1, 2, and 3 (Ali et al., 2021).

Result and Discussion
The mangrove nursery in Kebumen shows that planting media has an influence on the growth rate of both mangrove plants which are B. gymnorrhiza, R. mucronata and C. tagal.The three mangrove species showed significant differences in growth rates (P= 0.000); B. gymnorrhiza grows at the fastest rate, 1.35 cm per week, followed by growth R. mucronata (0.97 cm per week) and C. tagal (0,09 cm per week).The differences of planting media were also affecting the mangrove growth significantly (P= 0.020).The analysis of planting media, it shows that the mud:husk-charcoal 1:1 (T4) mixture has the significant influence on mangrove growth, followed by other planting media combinations (Table 1.).
The growth rate of the B. gymnorrhiza using a mixed planting medium of mud and husk charcoal was 1.35 cm.week -1 , this result is much greater than other studies using ordinary mud as a planting medium which about 0.33 cm.week -1 (Permatasari and Kusmana, 2011).Whereas, the results of this study are somewhat similar with the findings of Prambudy et al. (2023) research, which planted B. gymnorrhiza at a growth rate of 1.40 cm.week -1 in soil media.The husk charcoal and mud mixture provides a cavity in the soil between the soil particles that maintains water and increases the amount of soluble nutrients.The data shown in Table 2 indicates the treatment with the highest water content also had the highest concentration of phosphate (0.045%).Other nutrition elements, though, have not altered as significantly.
Husk and husk charcoal can be used as a nursery media to unlock the soil.A good nursery media in mangrove nurseries is one which is not excessively dense.This will facilitate the growth and development of plant roots, and can also help absorption of water, air, and nutrients properly.Another can easily obtain the media at a relatively low price (Dewi et al., 2020).Research findings related to Figure 3, which indicates that the T4 (mud:husk charcoal 1:1) treatment had the highest root biomass, particularly in B. gymnorrhiza and R. mucronata, additionally reinforce this perspective.According to Taek (2016), husk charcoal has a pH of 6.8 and contains 0.3% N, 15% P2O5, 31% K2O, and a number of other minerals.As a soil restoration material, husk charcoal can enhance plant growth and improve soil characteristics in land rehabilitation (Kusuma et al., 2013).
The nutrients nitrogen, phosphorus, and Cation Exchange Capacity (CEC) are important for plant growth since they are involved in metabolic processes and end up as components of the plant's constituents.The mangrove nursery medium's total N concentration varied between 0.25 and 0.34%.The range of the P elements was between 0.038 and 0.045%, nevertheless the soil fertility is still low.P components in soil are derived from minerals, synthetic fertilizers, and organic materials.The amount of organic matter in the media affects the content of N and P elements.Due to the moderate amount of organic material present, the total P and N elements in all of the nursery medium used in this study are categorized as moderate.
The experiment conducted at the TWA Angke Kapuk Jakarta site that there is not a significant distinction in planting media between the growth of B. gymnorrhiza and R. mucronata mangroves (P= 0.320).Due to their dissimilar development rates and habitat ranges, B. gymnorrhiza and R. mucronata present different growth rates (P= 0.000).R. mucronata lives in the seaward zone, which is an area that is frequently inundated, has soft substrates, and is greater in salinity than the landward zone, where B. gymnorrhiza grows most ideally.Research on the C. tagal species was not conducted because there does not a species which lives the TWA Jakarta mangrove area.
Results showed that there were significant differences in both mangrove species and locations when B. gymnorrhiza and R. mucronata were compared for growth in two different locations (TWA Jakarta and Kebumen) (P= 0.000).In TWA Jakarta, both mangrove species are growing rapidly (Table 3.).B. gymnorrhiza grew significantly faster at the TWA Jakarta site because the media therein had a salinity of less than 11 ppt, which is suitable for this species growth, in contrast to the salinity of over twenty ppt at the Kebumen site.
The study's findings show that the total, a, and b chlorophyll contents are within the appropriate range (Figure 1.).The process of photosynthesis and plant metabolism are also indicated by the amount of chlorophyll present.Variations in leaf chlorophyll levels may provide information about the physiological condition of leaves or plants, considering chlorophyll content a necessary metric measurements (Kamble et al., 2015).A plant's health is highly correlated with its chlorophyll level (Pérez-Patricio et al., 2018).Significant variations were observed between the three species of mangroves in terms of both total and chlorophyll-a concentration.The highest concentration of chlorophyll-a and total chlorophyll is found in C. tagal, which is followed by R. mucronata and B. gymnorrhiza.In contrast, there were no significant differences in chlorophyll-b amounts among these three species.At the Kebumen nursery, the chlorophyll-a content of R. mucronata ranges from 8.2 to 12.7 mg.g -1 dw, while that of C. tagal is 11.9-16.2mg.g -1 dw for chlorophyll-a and 6.7-9.0 mg.g -1 dw for chlorophyll-b.This chlorophyll content is much higher than that of the investigations conducted by Herteman et al. (2011), which found that the chlorophyll-a content in R. mucronata was among 3.01 and 4.01 mg.g −1 dw, and in C. tagal, it was between 2.88 and 3.28 mg g −1 dw.Several decades ago, mangrove areas in several regions in Indonesia experienced damage or disturbance (Ardli et al., 2015) Sedimentation, inappropriate resource exploitation, illegal cutting of mangrove vegetation and conversion, population migration, and other factors such as the absence of stakeholder integration for sustainable management of mangrove areas or ecosystems are among some of the causes of the decline in circumstances (Yuwono et al., 2007;Ardli and Wolff, 2009;Hinrichs et al., 2009;Holtermann et al., 2009;Prasetyo et al., 2017).Information from this study is expected to exhibit that a number of input parameters, particularly an abundance of good-quality seeds, can affect the success of mangrove planting.In three years, the government plans to restore 600,000 hectares of mangroves, and this will help achieve the target considerably.

Conclussion
The growth of mangrove seedlings was found to be influenced by the type of media, yet unaffected through the chlorophyll content or the ash-free biomass of the roots, stems, or leaves.Three species of mangroves differ regarding growth rate, biomass of roots, stems, and leaves, and chlorophyll content.The study might offer knowledge about methods to select and employ the most appropriate media for effectively producing high-quality seeds, which would help Indonesia's efforts to rehabilitate mangroves.

Table 1 .
Duncan comparison means test of mangrove seeding based on growth rate (cm.week -1 ) at Kebumen.

Table 2 .
Total macro nutrients, water content and total organic of the planting media.

Table 3 .
Comparison of mangrove growth rate (cm.week -1 ) were planted in TWA Jakarta and Kebumen.