Screening of Azotobacter strains from rice plant rhizosphere for phosphate solubilizing properties

Azotobacter is a plant growth promoting bacteria which solubilize phosphorous and make it available for plants. In the present study the efforts have been taken to fulfill the aim to isolate, characterize and screen Azotobacter for phosphate solubilization from the rice rhizosphere of Durg district. Total 8 strains of Azotobacter were isolated from different rice fields. It was observed that all the strains were found to be phosphate solubilizing but in different quantity. RAZB6 is highest phosphate solubilizer (234.4±1mg/L) and RAZB4 shows minimum (82.09±1mg/L) quantity of phosphate solubilization. Since phosphorous is necessary for the plants proper development and it increases the growth of rice plant and make soil more fertile for other plants growth also so they must be commercialized and used more and more in the crop fields other than the agrochemicals.

Karakter Rhizobakteri Pelarut Fosfat Potensial dari Rhizosfer Tumbuhan Mangrove Teluk Awur Kabupaten Jepara secara Mikrobiologi

Ekosistem mangrove terdiri dari komponen penyusun komunitas mangrove yang berinteraksi dengan faktor lingkungan di habitat tersebut. Ekosistem ini mudah mengalami kerusakan akibat kondisi pasang naik dan pasang surut wilayah perairan laut maupun hilir sungai, yang bermuara ke perairan laut. Peran penting ekosistem ini adalah dalam perlindungan daerah pesisir karena mampu melawan kerusakan yang disebabkan oleh perairan laut, seperti tsunami dan badai siklon tropis. Akan tetapi, ekosistem ini sering tidak diperhatikan atas fungsi tersebut. Ekosistem ini dilindungi di dunia karena memiliki tingkat kerusakan komponen penyusun yang tinggi. Ekosistem mangrove Teluk Awur yang terletak di Kabupaten Jepara, Provinsi Jawa Tengah, merupakan salah satu ekosistem mangrove yang mengalami kerusakan cukup parah karena perluasan lahan budidaya ikan (tambak), sehingga mendorong terjadinya erosi pantai. Peremajaan kembali dan konservasi ekosistem mangrove dapat dilakukan dengan menggunakan bakteri tanah yang mampu mendukung pertumbuhan tanaman atau yang biasa disebut Plant Growth Promoting Rhizobacteria (PGPR). Salah satu mekanisme pendukung pertumbuhan tanaman oleh kelompok PGPR dapat dilakukan dengan aktivitas pelarutan fosfat karena fosfat dalam tanah berada dalam bentuk senyawa yang sulit diserap oleh tanaman. Penelitian ini bertujuan untuk memperoleh isolat Rhizobakteri pelarut fosfat yang unggul dalam melarutkan fosfat secara in-vitro dan mengetahui karakter isolat yang diperoleh. Isolasi dan penapisan rhizobakteri pelarut fosfat dilakukan menggunakan medium Pikovskaya agar. Karakterisasi isolat potensial secara mikrobiologi dan uji aktivitas biokimia. Hasil penelitian menunjukkan bahwa rhizobakteri pelarut fosfat potensial yang berhasil diisolasi, secara mikrobiologi teridentifikasi ke dalam genus Enterobacter. Mangrove ecosystems consist of constituent components of mangrove communities that interact with environmental factors in the habitat. This ecosystem is susceptible to damage due to the high tide and tidal conditions of the sea and downstream rivers that flow into the ocean waters. The important role of this ecosystem is in the protection of coastal areas because it is able to resist damage caused by marine waters such as tsunamis and tropical cyclone storms. However, this ecosystem is often overlooked to these functions. This ecosystem is protected in the world because it has a high level of damage to its constituent components. Mangrove ecosystem of Teluk Awur, which is located in Jepara Regency, is one of the mangrove ecosystems that suffered severe damage due to the expansion of fish farming land (ponds). Rejuvenation and conservation of mangrove ecosystems can be done by using bacteria that support mangrove plant growth, which commonly called Plant Growth Promoting Rhizobacteria (PGPR). One of the supporting mechanisms of plant growth by the PGPR group can be carried out with phosphate dissolving activity because phosphate in the soil is in the form of compounds that are difficult to absorb by plants. This study aims to obtain potential phosphate solubilizer Rhizobacteria in dissolving phosphate in-vitro and to determine character of the obtained isolate. Isolation and screening of potential phosphate solubilizer Rhizobacteria were carried out using Pikovskaya agar medium. Microbiological characterization of potential isolates was carried out based on microbiological and/or biochemical activity. The results showed that potential phosphate solubilizer Rhizobacteria, microbiologically identified to genus of Enterobacter.

Aplikasi Bradyrhizobium japonicum DAN Aeromonas salmonicida Pada Penanaman Kedelai Di Tanah Asam Dalam Percobaan Rumah Kaca

Kedelai (Glycine max) merupakan salah satu tanaman pangan yang dibudidayakan. Kebutuhan kedelai yang selalu meningkat setiap tahun mendorong usaha peningkatan terhadap produksi kedelai. Upaya peningkatan produksi dapat dilakukan dengan menggunakan pupuk hayati dan memanfaatkan lahan yang kurang produktif di Indonesia. Pupuk hayati yang digunakan mengandung isolat Bradyrhizobium japonicum sebagai penambat nitrogen dan Aeromonas salmonicida sebagai pelarut fosfat. Isolat yang terdapat dalam pupuk hayati diharapkan dapat membantu pertumbuhan kedelai di tanah asam dengan menyediakan unsur nitrogen dan fosfat. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian pupuk hayati yang terdiri atas B. japonicum (BJ 11 wt) dan A. salmonicida pada penanaman kedelai di tanah asam. Tanaman percobaan dibuat dalam empat kelompok, yaitu dengan inokulasi Isolat BJ 11 (wt), PP, BJ 11 ditambah dengan PP, dan tanpa inokulasi (kontrol). Hasil penelitian menunjukkan bahwa aplikasi B. japonicum dan A. salmonicida cenderung dapat meningkatkan laju pertumbuhan tanaman, jumlah daun, dan bobot kering akar. Kata Kunci: Bradyrhizobium japonicum, Aeromonas salmonicid, Tanah Masam dan Kedelai Soybean (Glycine max) is one of cultivated food crops. Since the need of soybean is always increased every year, it needs some efforts to improve soybean production. One of the steps can be done is by using biofertilizer in a less productive land such as acid soil. Biofertilizer that used in this study consist of Bradyrhizobium japonicum as nitrogen fixation and Aeromonas salmonicida as phosphate solubilizer bacteria (PP). Isolates contained in the biological fertilizer is expected to help the growth of soybean in acid soils by providing elements of nitrogen and phosphate. The aim of this research was to know the effect of using biofertilizer consisted of B. japonicum (BJ 11 wt) and A. salmonicida (PP) to soybean growth in acid soils. The experiment was arranged with four group treatments that were inoculation with BJ 11 (wt), PP, BJ 11 plus PP, and without inoculation (as control). The results showed that the application of B. japonicum and A. salmonicida as inoculant mixture tend to increase plant growth, leaf number, and dry root weight. Keywords: Bradyrhizobium japonicum, Aeromonas salmonicid, Acid Soil and Soybean

Phosphate Solubilizing Bacteria in Certain Agricultural Crop Soils of Delhi

Phosphate solubilizing bacteria (PSB) helps in the solubilization of insoluble phosphates and thus lead to increase in crop yields. A study was conducted to isolate and characterize biochemically PSB from different agricultural crop soils of Delhi such as Garlic, Radish, Chilli, Onion and Cabbage. PSB were isolated in Pikovskaya solid medium and formation of solubilization (halo) zone was measured. 16 PSB were isolated and identified. The selected PSB differed in phosphate solubilizing efficiency, production of organic acids and phosphatases. Citrobacter sp. and Pseudomonas sp. were dominant in all the crop plants. Among all the isolates, Pseudomonas sp. proved to be an efficient phosphate solubilizer.

Effect of Yeast Based Biofertilizer combined with bacteria on Mustard Plant Growth

Biofertilizers are commonly defined as microbial inoculants which are capable of mobilizing important nutrient in the soil from non-available to available form for the plants through their biological processes. Hence to increase the productivity of the soil, the use of biofertilizer is necessary. Candida yeast as a phosphate solubilizer and decomposer. Azotobacter bacteria as a nitrogen-fixing bacteria and Bacillus as a phosphate solubilizer. The combination of these microorganisms as biofertilizer needs to be tested its effect against mustard (Brassica juncea L.) plant growth.The results showed that the combination of Bacillus Candida obtained the highest yield among other biofertilizer treatments with a value of 13.6 cm at plant height, 4.96 grams in wet weight and 2.29 grams in dry weight. The combination of Azotobacter Candida showed the highest result on the parameter of width and number of leaves with the values of 20.3 cm and 5.3. Combination of Azotobacter Bacillus Candida showed the highest yield on the root length parameter with a value of 5.0 cm. The addition of biofertilizer is expected to reduce pollution on the soil due to residues produced by chemical fertilizers.Keyword : Azotobacter, Bacillus, Biofertilizer, Candida, Mustard Plant

Plant Beneficial Endophytic Bacteria from the Ethnomedicinal Mussaenda roxburghii (Akshap) of Eastern Himalayan Province, India

Mussaenda roxburghii are very important ethnomedicinal plant, used for its various applications from the ancient period. The role of their associated plant beneficial endophytic bacteria was evaluated, which were previously untapped. Among the isolates, PAK6 was identified as efficient phosphate solubilizer, quantified by the molybdenum blue method. Four isolates PAK1, PAK2, PAK3, and PAK8 were able to synthesize significant level of IAA in the presence and absence of tryptophan. Isolates PAK1 and PAK9 were able to produce siderophore on CAS agar media, PAK2 and PAK9 were able to produce HCN, and PAK7 and PAK8 were able to grow on N2-free medium. All the isolates were able to produce a moderate level of polysaccharide and tolerate up to 10% of NaCl. Isolates PAK3, PAK6, PAK7, and PAK8 were able to grow well at pH 5.0 and isolates PAK2, PAK7, and PAK8 were able to tolerate 600 μg mL−1 of Al+3, while all the isolates except PAK1 showed a tolerance to 600 μg mL−1 of Mn+2 tested. Endophytic bacterial isolates PAK6 and PAK9 were effective against Sclerotinia sclerotiorum and Sclerotium rolfsii.

Recovery of degraded areas revegeted with Acacia mangium and Eucalyptus with special reference to organic matter humification

Humidified fractions of organic matter and soil microorganism populations are used as environmental quality indicators. This work aimed to study the changes in chemical and microbiological soil attributes, as well as in the humidified fractions, of the organic matter in a substrate from a clay extraction area cropped with Brachiaria mutica, Acacia mangium and Eucalyptus. In the Eucalyptus area, the P contents increased linearly with planting time. However, only at the twelfth year, differences between Eucalyptus and B. mutica areas have occurred. In the A. mangium area, such differences in the P content occurred at the third year with increment of 43%, at the 0-10 cm layer, in relation to B. mutica. Also, at the 0-10 cm layer, the total carbon contents were 98%, 78%, 70% and 40% higher than those found in Eucalyptus with three, five, twelve years of age and in the B. mutica area, respectively. Such increments also occurred in the humidified fractions, especially in the fulvic acids (C FA). The population of microorganisms was higher in the A. mangium area, mainly in the summer, where it was observed a positively correlation with total carbon (total bacteria, r = 0.96**, total fungi, r = 0.91*, and phosphate solubilizer microorganisms, r = 0.98**) and with the C FA fraction (total bacteria r = 0.96**, total fungi, r = 0.90*, and phosphate solubilizer microorganisms, r = 0.98**). The use of A. mangium led to improvements in the chemical and microbiological soil attributes in the substrate