Judul: Keragaman dan Kelimpahan Lumut Hati Epifit di Kebun Raya Bogor
Abstrak: Indonesia has a high biodiversity of plants including bryophytes. Studies on the bryophyte diversity of Indonesia has not comprehensively done. Bogor Botanical Garden is one of the ex-situ conservation providing suitable habitat for bryophytes. Studies on the hepaticae of Bogor Botanical Garden are urgently needed. In this studies, bryophyte sampling were done in three blocks where the collection of Meliaceae, Myrtaceae and Lauraceae. Sampling was done based on the difference of growth position of tree (0-100 cm and 100-200 cm above ground) and at the difference of compass point (west, east, south, and north). Specimens checklist of bryophytes in the Herbarium Bogoriense (BO) as well as the herbarium specimens were studied. There are 92 species leafy liverworts are known at the sampling areas in Bogor Botanical Garden and herbarium specimens record at BO. There are 33 species leafy liverworts of epiphyte hepaticae were collected. In this studies, 7 species are recorded as the same as the BO specimens, the rest of 26 species are different with BO specimens. Lejeuneaceae has the highest diversity number, and highest percentage of coverage. Myrtaceae block has the highest diversity number and species abundance of hepaticae, that is 17 species and 52.9% of the total coverage. All of the blocks, position of tree 0-100 cm has the highest species abundance and frequency. A determination key to the species epiphytic hepaticae of Bogor Botanical Garden is presented.
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Judul: Lumut Terestrial dan Ganggang Asosiasinya di Kebun Raya Bogor
Abstrak: Bogor Botanical Garden is an ex-situ conservation which may serve as habitat for bryophyte. Terrestrial bryophyte usually grow on various substrates in shaded habitat or open habitat, such as roadside, along ditches, and rivers. One of the bryophytes benefit in ecosystem is to provide microhabitat for algae. This research was carried out to inventory the bryophyte species grow on terrestrial substrate, and to study their diversity and algal association. The bryophyte were collected on various terrestrial substrates (soil, root, and rock). Quadrates of 25 × 25 cm² were used to sample bryophytes along 30 m transect on three blocks which is dominated by plants with different family, i.e. Meliaceae, Myrtaceae, and Lauraceae to study the diversity. Bryophyte were also sampled used sub-quadrates of 2,5 × 2,5 cm² in the quadrate of 25 × 25 cm² to sample algae associated with bryophyte. Forty three species of terrestrial bryophytes were identified, including 33 species of mosses and 10 species of liverworts. The bryophytes diversity was significantly different when compared to different blocks (p < 0,05). The highest diversity of bryophyte was on block Meliaceae which were more intensively shaded than on any other block. The bryophytes composition was different inter block. Fissidens crassinervis var. laxus, Isopterygium bancanum, and Taxiphyllum cf. taxirameum were dominated on three blocks in Bogor Botanical Garden. These three bryophytes species are commonly grow on soil and roots. Thirteen morphospecies of algae were found in association with terrestrial bryophyte, i.e. Cyanophyta, Chrysophyta, and Chlorophyta.
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Judul: Sintesis nanopartikel Cu2ZnSnS4 menggunakan teknik hidrotermal
Abstrak: Nanopartikel Cu2ZnSnS4 (CZTS) merupakan semikonduktor yang berpotensi sebagai fotokatalis untuk reaksi fotodegradasi zat pewarna. Semikonduktor ini memiliki sela pita yang jauh lebih kecil dibandingkan dengan semikonduktor TiO2, sehingga memungkinkan dapat berkerja hanya dengan paparan sinar matahari. Nanopartikel Cu2ZnSnS4 telah berhasil disintesis menggunakan teknik hidrotermal dengan suhu 200 oC selama 24 jam. Larutan Cu2ZnSnS4 dinetralkan menggunakan amonium hidroksida dan dialiri gas N2 sebelum proses hidrotermal. Hasil analisis mikroskop elektron pemayaran menunjukkan nanopartikel Cu2ZnSnS4 mengalami aglomerasi karena memiliki ukuran partikel yang besar. Hasil analisis difraktogram sinar-X menunjukkan bahwa Cu2ZnSnS4 yang dihasilkan memiliki struktur kesterit dengan senyawa fase sekunder yang terbentuk adalah CuS, ZnS, dan Cu2SnS3. Hasil uji fotodegradasi menunjukkan bahwa senyawa hasil sintesis memiliki kemampuan degradasi dibawah sinar matahari lebih baik dibandingkan dengan TiO2. Namun, pada paparan sinar UV, TiO2 mendegradasi biru metilena lebih baik daripada senyawa hasil sintesis. Kapasitas adsorbsi terhadap biru metilena sebesar 2.6780 mg/g menunjukkan bahwa senyawa hasil sintesis tidak mampu mengadsorpsi dengan baik, sehingga disimpulkan bahwa hilangnya biru metilena dari larutan disebabkan oleh fotodegradasi, bukan oleh adsorpsi
Keyword: band gap, Cu2ZnSnS4, kesterite, photocatalyst, semiconductor