Judul: Interspecies protoplasts fusion between citrus siam simadu (Citrus nobilis Lour.) and citrus mandarin satsuma (C. unshiu Marc.)
Abstrak: Somatic hybridization is an important tool for supplying new varieties to be used directly as cultivar genetic improvement programs. In citrus, this technology has been extensively used and has many important implipications. The objectives to the research are produceed citrus somatic hybrids between citrus siam Simadu and Mandarin Satsuma with chemical fusion (PEG). Protoplasts of siam Simadu from calli with Mandarin Satsuma from mesophyll-derived protoplasts were regenerated by somatic embryogenesis. Concentration and duration of incubation in a solution of PEG strongly affected the fusion induction of siam Simadu with Mandarin Satsuma. High concentrations of PEG can increase the frequency of fusion, while the low concentration produces a low frequency of fusion. The result showed that protoplasts from embryogenic callus of Simadu tangerine and in vitro leaf of Mandarin Satsuma can be isolated in large numbers by using a combination of cellulase Onozuka R10, Yakult Yakult% 1% with R10 Maserozim in CPW solution. Protoplasts are purified with a mixture of 25% sucrose with 13% mannitol. Protoplast density produced from embryogenic callus is 15.7x105 protoplasts / g callus and 13x105 protoplasts/ g in vitro leaf. The concentration of PEG used to induce fusion between mesophyll protoplasts Mandarin Satsuma and siam Simadu callus affect the average number of protoplasts fusion. Average number of protoplasts were fused by using PEG 4% are 3.3 hetero fusion, 5.0 homo fusion and multi-fusion. Average number of protoplasts were fused by using PEG 30% are 4.7 hetero fusion, 6.7 homo fusion 6.7 and 7.7multi-fusion. The success of fusan regeneration on regeneration medium is influenced by PEG concentration used for induction of fusion. Protoplasts were fused with PEG only 4%, which can regenerate to form cell walls, making cell division, colony cells, micro-callus and somatic embryo. Protoplasts were fused with PEG 30% can only be regenerated to form the cell wall and cell division. Giving light to the culture after 2 weeks may accelerate cell division that can form colonies of cells. Dilutions of cell suspension with the same medium (without 2, 4-D) can accelerate the growth and development of the protoplasts formed colonies of cells, micro-callus and somatic embryos. MW medium is best used in the fusion because it can encourage of somatic embryos directly. Addition of ABA 0.5 mg / l in the media can produce somatic embryos and GA3 0.5 mg / l can germinate mature somatic embryos to plantlets with 76% germination efficiency. Somatic hybrids were germinated, then trasfered to a medium culture, and finally grafted in greenhouse. The hybrids were confirmed by growth of in vitro culture, morphology, cytology (chromosome number), molecular analysis (ISSR), and contain of chlorophyl Keywords: Citrus, male sterility, chemical fusion, somatic embryogenesis, morphology,
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Judul: Study Regeneration of Tengerine Citrus Batu 55 (Citrus reticulata) Through Somatic Embryogenesis Path Way
Abstrak: The global world market of citrus fruit that is consumed in fresh form to the current needs to fill a category of fruit that do not have seeds, easy to peel and has an attractive color (pigmented). Tangerine citrus Batu 55 is one of the mainstay of fresh fruit horticulture. Tangerine citrus Batu 55 has superior character who naturally have had so distinguished by citrus Siam but the characters are not as good as tangerine imports. Somatic embryogenesis is an important tool for supplying new varieties to be used cultivar genetic improvement programs in citrus, this technology has been extensively used and has many important implications. The objective of this research is to produce somatic embryos of Tangerine citrus Batu 55 from nucellar embryo. The research comprised: embryogenic callus induction, callus prolifertation, maturation of somatic embryo, germination of somatic embryo, shoot multiplication, roots induction, chromosome counting, acclimatization and grafting. The results showed that the medium of Murashige & Tucker + 3 mg/l BAP + 1 mg/l 2,4-D + 500 mg /l malt extract increased the percentage of the callus formation up to 40% after 4 weeks with total number of pre-embryos (PEM ) 31.0. The medium proliferation used was MS with the addition of vitamin Morell & Wetmore (MW) +3 mg/l BAP+300 mg/l casein hydrolisat. These medium improved callus diameter up to 2.3 mm after 4 weeks cultured. Maturation of embryos was obtained by transferring globular structure in the medium MW + 2.5 mg/l ABA + 500 mg/l malt extract. These medium increased the percentage of mature somatic embryo up to 98% after 4 weeks cultured. Somatic embryos up to 84% germinated when the cotyledons grown in the medium MW + 2.5 mg/l GA3. The shoot multiplication containing MW medium + 7 mg/l biotin +500 mg/l malt extract was able to produce the highest percentage of shoot multiplication up to 86 %. The root induction containing MS medium + 3 mg/l IBA was able to produce the highest percentage of root induction up to 86%. Acclimatization of plantlets with roots increased survival rate up to 90% after 5 weeks acclimatization.
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Judul: Fenomena Arus Rabak (Rip Current) Di Kawasan Pantai Panjang, Kota Bengkulu
Abstrak: Tingginya kunjungan wisatawan namun minim pengetahuan tentang kondisi pantai, dapat menyebabkan adanya risiko kecelakaan pantai yang tinggi. Arus rabak adalah salah satu penyebab terjadinya kecelakaan pantai. Tercatat sebanyak 35 kasus terseretnya wisatawan pernah terjadi di Pantai Panjang dari tahun 2009 hingga tahun 2021. Penelitian ini bertujuan menggambarkan kondisi oseanografi pada lokasi yang berpotensi munculnya arus rabak berdasarkan musim, jenis arus rabak, serta menjelaskan karakteristik arus rabak melalui ciri dan proses pembentuk arus rabak. Lokasi penelitian dilakukan di Pantai Panjang, Kota Bengkulu. Analisis arus rabak menggunakan model SWAN, kedalalaman perairan, angin dan citra satelit. Topografi dasar laut pesisir Bengkulu relatif landai. Gelombang signifikan tertinggi terjadi pada bulan Januari 2017 yaitu 0.25 m dengan periode gelombang terlama terjadi pada bulan April 2021 yaitu 1.63 s. Karakteristik tipe gelombang pecah Pantai Panjang yaitu plunging. Fenomena arus rabak kerap terjadi di Pantai Panjang dengan jenis bar-gap rips. Pembentukan arus rabak dipengaruhi oleh kondisi topografi. Arus rabak yang terjadi di Pantai Panjang dapat ditemui s
Keyword: Arus rabak, Gelombang, Pantai Panjang, SWAN, Topografi, Panjang Beach, Rip Current, Topography, Wave