Pemanfaatan Bakteri Kitinolitik dalam Menghambat Pertumbuhan Curvularia SP. Penyebab Penyakit Bercak Daun pada Tanaman Mentimun

A study on about the utilization of chitinolytic bacterial isolates to inhibit growth of Curvularia sp. causal agent of leaf spot disease of cucumber was done in Laboratory of Pest and Disease, Medan Johor, UPT-Balai Protection Plant and Horticulture I and Laboratory Microbiology Departement of Biology, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan. Six chitinolytic isolates were tested in vitro to inhibit growth of Curvularia sp.. The result showed that Bacillus sp. BK13 inhibited more with inhibition zone of 2,75 cm and Enterobacter sp. BK15 with inhibition zone of 2,55 cm, whereas Enterobacter sp. PB17 showed the lowest inhibition zone of 1,3 cm. Soaking seed treatment in chitinolytic bacterial suspension reduced the percentage of leaf spot. Enterobacter sp. BK15 showed more ability (50%) to inhibit leaf spot attack

Potensi Bakteri Kitinolitik dalam Pengendalian Aspergillus Niger Penyebab Penyakit Busuk Pangkal Akar pada Tanaman Kacang Tanah

A study of chitinolytic bacteria ability to control Aspergillus Niger, a causal agent of basal root rot of peanut seedlings was conducted in Pest and Disease Laboratory, Medan Johor and Laboratory of Microbiology, Department of Biology, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan. The purpose of study is to evaluate the ability of Bacillus sp. BK13, Enterobacter sp. BK15, Bacillus sp. BK17, Enterobacter cloacae LK08, Bacillus sp. KR05, and Enterobacter sp. PB17 to inhibit the growth of A. Niger on the peanut seedling. Antagonistic test showed that the most effective bacteria in inhibiting the growth of A. Niger was BK15 isolate with inhibition zone of 2,88 cm and BK13 isolate with inhibition zone of 2,69 cm, whereas the least effective bacteria was BK17, with inhibition zone of 2,30 cm. Chitinolytic bacterial isolates used to cover peanut seed through soaking enabled to reduce seed basal root rot. BK15 isolate showed potential to reduce the basal root rot by 58,82% while the lowest inhibition was BK13 by 47,06%

Isolasi Dan Uji Potensi Isolat Bakteri Pelarut Fosfat Dan Bakteri Penghasil Hormon Iaa (Indole Acetic Acid) Terhadap Pertumbuhan Kedelai (Glycine Max L.) Pada Tanah Kuning

Biofertilizer is a safe alternative fertilizer instead of various chemical fertilizers for increasing plant productivity which can minimize the ecological damage. There are plant symbiotic-soil bacteria which can solubilize phosphate or produce IAA. The objectives of this research are to determine the best soil bacteria in producing IAA or solubilizing phosphate and to know their roles in promoting plant growth in unfertile soil. As many as 8 isolates of phosphate solubilizing bacteria and 5 isolates of IAA producing bacteria were found. Among those isolates, there were 2 potential isolates (P2 & P4) that were able to solubilize phosphate and 1 potential isolate (I3) that was able to produce IAA. Isolate P4 produced holozone as wide as 1.45 cm and isolate P2 was 1.3 cm. Meanwhile, isolate I3 produced the highest concentration of IAA compared to the other isolates, that was 33.3 ppm. These isolates were applicated further on unfertile soil (yellow soil) as a medium for soybean growth. Soybeans have been grown for 10 weeks to observe the effect of those potential isolates on plant growth and productivity. The result showed that application of isolate I3 was able to promote plant growth and increase plant productivity better than the other isolates as well as controls (fertile and unfertile soil). It promoted the soybean growth such as plant height was 58,8 cm; plant fresh weight was 3.5 g; plant dry weight was 1.55; pod fresh weight was 1.23; pod dry weight was 1.03; the amount of the pod was 3 and the number of the seed was 7

Meristematic Shoot Tip Culture Obtain Good Quality Seedling of Citrus (Citrus Nobilis Var. Brastepu) Free From Citrus Vein Phloem Degeneration

Meristematic shoot tip culture to obtain good quality seedling of citrus (Citrus nobilis Var. Brastepu) free from citrus vein phloem degeneration (CVPD) is explained in this research. The method is conducted by using a diseased plant and is then propagated in optimum conditions. The research is conduted in Tissue Culture Laboratory Department of Biology, University of North Sumatra, Indonesia. Optimum conditions for citrus propagation have been obtained to produce good quality of Citrus seedlings that is free from CVPD. The analysis of the DNA using PCR method has confirmed that the seedlings are healthy and free from CVPD. Genomic analysis using 10 RAPD markers show the planlets regenerated from the cultures are 100% similar with the mother plant