AbstrakBioreaktor perendaman sesaat (BPS) telah digunakan secara luas untuk propagasi skala massal berbagai tanaman penting, termasuk tanaman tebu. BPS menyediakan sistem kultur semi-otomatis dan kondisi optimal bagi pertumbuhan tanaman. Beberapa faktor menentukan pertumbuhan tanaman pada BPS, salah satunya densitas dari eksplan. Oleh karena itu, penelitian dilakukan untuk menentukan bobot awal yang optimal untuk kalus tebu yang dikulturkan pada BPS, serta mengevaluasi pengaruh perbedaan bobot awal kalus tersebut terhadap proliferasi dan regenerasi kalus tebu. Kalus tebu diinduksi dari daun muda yang masih menggulung dari empat varietas tebu unggul Indonesia. Bobot awal kalus yang dikultur ke dalam bejana TIB yaitu 0,05 g; 0,1 g; 0,2 g; 0,5 g; dan 1,0 g untuk setiap bejana. Kalus kemudian melalui tahap proliferasi pada BPS sebanyak tiga siklus, kemudian kalus diregenerasi pada BPS dengan perlakuan auksin dan sitokinin. Hasil penelitian menunjukkan bahwa 0,2 g merupakan bobot awal kalus yang efisien untuk proliferasi kalus tebu pada TIB, dimana eksponensial multiplikasi kalus tercapai pada bobot awal tersebut, yaitu untuk masing-masing varietas 130,3 kali (PSKA 942), 136,8 kali (PS 094), 21,3 (PS 881), dan 12,9 kali (PS 091) setelah 12 minggu. Densitas kalus pada TIB berkorelasi negatif dengan karakteristik fisikokimia medium. Hal ini menggambarkan variasi intensitas pertumbuhan dan metabolisme kalus dengan adanya perbedaan densitas pada BPS. Penggunaan BAP 0,2 mg L-1 bersama kinetin 0,2 mg L-1 paling sesuai untuk memacu regenerasi kalus tebu dengan menghasilkan jumlah tunas terbanyak dalam waktu relatif lebih cepat (1 – 2 minggu lebih cepat) dibandingkan perlakuan lainnya dan dengan tingkat kejadian pencoklatan yang rendah.[Kata kunci: kultur in vitro, kultur cair, proliferasi]AbstractTemporary immersion bioreactor (TIB) has been utilized for the mass-scale propagation of many important plants, including sugarcane. TIB facilitates a semiautomated culture system and provides optimal conditions for plant growth. Several factors determine plant growth in the TIB, such as explant density. Therefore, an experiment was carried out to determine the optimal initial weight of sugarcane calli and to evaluate its effect on the proliferation and regeneration in TIB. Sugarcane calli were induced from spindle leaves isolated from four Indonesian prime sugarcane varieties. The initial weights of the calli cultured in the TIB flasks were 0.05 g, 0.1 g, 0.2 g, 0.5 g and 1.0 g per flask. The calli were proliferated through three cycles in TIB, and subsequently regenerated in TIB with auxin and cytokinin treatments. The results of the experiments showed that 0.2 g was the most efficient initial weight for sugarcane callus proliferation in the TIB, resulting in an exponential multiplication rate of 130.3-fold (PSKA 942), 136.8-fold (PS 094), 21.3-fold (PS 881), and 12.9-fold (PS 091) within 12 weeks. In the TIB, callus density showed a negative correlation with the physicochemical properties of the medium, demonstrating various growth intensities or metabolic activities of calli at different densities in the TIB. The use of 0.2 mg L-1 BAP along with 0.2 mg L-1 kinetin was suitable for promoting the regeneration of sugarcane calli and producing the highest number of shoots in a relatively short amount of time (1 – 2 weeks faster) with low incidences of browning.[Keywords: in vitro culture, liquid culture, proliferation]

In vitro culture through microcutting technology can be used for clonal propagation of rubber (Hevea brasiliensis Muell. Arg.) rootstocks. Acclimatization of in vitro plantlets to ex vitro conditions is a major bottleneck in the micropropagation of many plants.This research was conducted to study the effect of plastic cover closed period and media composition on the survival rate of rubber plantlets. Plantlets derived from microcutting were planted on plastic pots containing a mixture of soil, cocopeat, dung manure, and sand or zeolite. The plantlets were then placed inside a closed transparent plastic cover that opened after 2, 3, 4 and 6 weeks. The cover was placed under tree canopy. The second experiment used the same media composition with or without cocopeat and with sand or zeolite. At 1.5 month after culture, observation was done on the number of survived plantlets, plantlet height and the percentage of rooted plantlets. The results show that the best coverclosed period was six weeks and the best growing medium was a mixture of soil, cocopeat, dung manure, and zeolite (6:2:1:1v/v). On the two combined treatments, the survival rate was 73.3% after 1.5 month of acclimatization. The use of zeolite and a higher soil percentage gave positive influences on rubber plantlet survival rate. The second experiment results confirmed that the use of zeolite was better than sand and the use of cocopeat was definitely needed. It can be concluded that the best of acclimatization of rubber plantlets from microcutting was on a medium mixture of soil, cocopeat, dung manure, and zeolite (6:2:1:1) and placed inside a closed plastic cover for six weeks before the cover was opened gradually.

Stevia (Stevia rebaudiana Bertoni) is a natural zero-calorie sweetener plant grown in a high population density.Tissue culture technique is useful for rapid mass propagationof plants to provide superior planting materials. Experimentswere conducted to increase growth and multiplication ofshoots and vigor of plantlets of stevia. Explants used wereapical and axillary buds from plantlets grown on MS mediumwithout plant growth regulators. Combinations of BA andIAA at different concentrations were used for shoot growthand multiplication, whereas plant growth retardants(ancymidol and paclobutrazol) and light intensity were usedfor plantlet vigor. The results showed that stevia explantscultured on MS medium without plant growth regulatorsproduced the highest shoots (4.5 cm) with two shoots perexplant. The best multiplication rate of shoots were found onMS medium added with 1.13 mg/L BA combined with0.35 mg/L IAA which produced on average 4.5 shoots and11.9 nodes per initial explant. Ancymidol and paclobutrazolconcentrations affected significantly growth and vigor ofstevia plantlets. Increasing the concentration of ancymidoland paclobutrazol decreased plantlet height and biomassfresh weight, but increased stem diameter. Paclobutrazol at0.1 mg/L was the best treatment to increase the vigor ofstevia plantlets. Light intensity at 20 µmol/m 2 /s gave betterplantlet vigor than other light intensities. It can be concludedthat multiplication of stevia shoots should be grown on MSmedium supplemented with 1.13 mg/L BA + 0.35 mg/L IAAand the vigor of the shoots can be increased by culturing onMS medium containing 0.1 mg/L paclobutrazol underfluorescence lamps with 20 µmol/m 2 /s light intensity.AbstrakStevia (Stevia rebaudiana Bertoni) adalah tanamanpemanis alami nir-kalori yang ditanam dengan kerapatanpopulasi yang sangat tinggi. Teknik kultur jaringan dapatdigunakan untuk perbanyakan tanaman secara massal dancepat untuk menyediakan bahan tanam unggul. Penelitiantelah dilakukan untuk meningkatkan pertumbuhan danmultiplikasi tunas dan keragaan planlet stevia. Eksplan yangdigunakan adalah tunas pucuk dan tunas samping dari planletyang ditumbuhkan pada medium MS tanpa zat pengaturtumbuh. Kombinasi BA dan IAA dengan konsentrasi yangberbeda digunakan untuk pertumbuhan dan multiplikasitunas, sedangkan zat penghambat tumbuh (ansimidol danpaklobutrazol) serta intensitas cahaya digunakan untukkeragaan planlet. Hasil penelitian menunjukkan bahwaeksplan stevia yang ditumbuhkan pada medium MS tanpa zatpengatur tumbuh menghasilkan tunas paling tinggi (4,5 cm)dengan dua tunas per eksplan. Multiplikasi tunas terbaikdiperoleh pada medium dengan BA 1,13 mg/L yangdikombinasikan dengan IAA 0,35 mg/L yang menghasilkan4,5 tunas dan 11,9 ruas per eksplan awal. Konsentrasiansimidol dan paklobutrazol berpengaruh nyata terhadappertumbuhan dan keragaan planlet stevia. Meningkatnyakonsentrasi ansimidol dan paklobutrazol menurunkan tinggiplanlet dan bobot basah biomassa, tetapi meningkatkandiameter batang. Paklobutrazol pada konsentrasi 0,1 mg/Lmerupakan perlakuan terbaik untuk meningkatkan keragaanplanlet stevia. Intensitas cahaya pada 20 µmol/m 2 /detikmemberikan keragaan planlet yang lebih baik dibandingkanintensitas cahaya yang lain. Dapat disimpulkan bahwamultiplikasi tunas stevia sebaiknya dilakukan pada mediumMS ditambah BA 1,13 mg/L + IAA 0,35 mg/L dan keragaanplanlet dapat ditingkatkan dengan menanam planlet padamedium MS ditambah paklobutrazol 0,1 mg/L di bawahlampu fluoresen dengan intensitas cahaya 20 µmol/m 2 /detik.

Liquid culture is commonly used to scale up in vitro culture production as well as to optimize the developmental phase of plant in vitro culture. One of the liquid cultures that has been used widely is temporary immersion system (TIS). The main problem of liquid culture is contamination. The use of antibiotics sometimes controls the contaminants less effectively and hinders the growth of plant culture. The purpose of this research was to determine sources of contaminant on whole sequence of TIS to identify and to prevent the emergence of the contaminants. Sampling method was applied to each section and stage of TIS culture and the contaminants found were identified. The results revealed that compartment of TIS was the main source of contaminant (100%). Furthermore, from all components of TIS compartment, washer (a small ring seal connecting screen disc and basket) was the main source of TIS contaminant (41.2%). Four contaminants found were identified as Bacillus macerans, Bacillus megaterium, Bacillus sphaericus and Bacillus firmus. Two times sterilization of washer in an autoclave at temperature of 121 oC and air pressure of 1 kg/cm2 for 20 minutes before and after being installed reduced the contamination level on TIS culture significantly.AbstrakKultur cair umumnya digunakan untuk meningkatkan skala produksi dan mengoptimalkan fase perkembangan kultur in vitro tanaman. Salah satu jenis kultur cair yang banyak digunakan adalah sistem perendaman sesaat (SPS). Masalah utama dalam kultur cair adalah kontaminasi. Penggunaan antibiotika terkadang kurang efektif dalam me-ngendalikan kontaminan dan menghambat pertumbuhan kultur tanaman. Tujuan dari penelitian ini adalah untuk mengetahui sumber kontaminan pada seluruh rangkaian kultur SPS serta mengidentifikasi dan mencegah munculnya kontaminan tersebut. Metode yang digunakan adalah  pengambilan contoh pada tiap bagian dan fase kultur SPS, serta kontaminan yang ditemukan kemudian diidentifikasi. Hasil penelitian memperlihatkan bahwa kompartemen SPS merupakan sumber utama kontaminan (100%). Selanjutnya, dari seluruh komponen kompartemen SPS, washer (cincin penutup yang menghubungkan penyaring dan keranjang) di dalam rangkaian SPS merupakan sumber utama kontaminan (41,2%).  Empat  kontaminan yang ditemukan diidentifikasi sebagai Bacillus macerans, Bacillus megaterium, Bacillus sphaericus dan Bacillus firmus. Sterilisasi cincin penutup sebanyak  dua  kali  dalam  autoklaf pada suhu 121 oC dan tekanan udara 1 kg/cm2selama 20 menit sebelum dan sesudah dirangkai secara nyata menurunkan tingkat konta-minasi pada kultur SPS.

Pengaruh jenis penutup botol kultur terhadap pertumbuhan planlet kelapa sawit (Elaeis guineensis Jacq.) Effect of different culture vessel closures on the growth of oil palm (Elaeis guineensis Jacq.