Memahami Komunikasi Tumbuhan-Tanah dalam Areal Rhizosfir untuk Optimasi Pengelolaan Lahan

Abstrak. Seperti halnya dunia manusia, tumbuhan juga mengembangkan sistem komunikasi untuk mencapai kesejahteraan hidupnya. Bahasa yang digunakan adalah senyawa kimia yang diproduksi oleh eksudat akar. Tumbuhan merupakan inisiator karena mereka yang memiliki tujuan untuk apa komunikasi dibangun. Tumbuhan mengeluarkan eksudat akar untuk memanggil atau untuk mengusir mikroba yang diinginkan. Tumbuhan mengirim surat undangan pada beberapa mikroba dengan mensekresikan eksudat akar. Untuk membangun asosiasi mikoriza tumbuhan mengeluarkan gula, asam amino dan strigolakton. Hal tersebut akan dibalas oleh fungi dengan mengeluarkan senyawa flavonoid yang menunjukkan spesifikasi jenis inang-mikoriza. Hadirnya senyawa flavonoid merupakan undangan bagi rhizobium pada tanaman legum untuk membangun asosiasi. Tumbuhan akan menyeleksi rhizobium yang akan diajak berasosiasi dengan mensekresikan senyawa kanavanin yang bersifat toksik. Kesalahan dalam mengeluarkan eksudat akar merupakan surat undangan yang keliru bagi tumbuhan. Dosis senyawa stigolakton yang terlalu rendah tidak akan dapat membentuk asosiasi mikoriza tetapi yang berkembang adalah patogen. Walaupun tumbuhan menghasilkan senyawa fitoantisipin untuk mencegah serangan patogen dan fitoaleksin ketika patogen sudah menginfeksi. Komunikasi akar dengan akar tumbuhan lain dilakukan dengan menghasilkan senyawa alelopati untuk membatasi pertumbuhan akar di sekelilingnya yang dianggap sebagai pesaing. Tanaman invasif atau gulma umumnya selain menghasilkan alelopati juga memproduksi katekin yang dapat membunuh mikroba menguntungkan pada tumbuhan setempat. Akibatnya tumbuhan lokal akan rentan terhadap serangan penyakit dan berujung pada kematian. Selain alelopati, untuk merespon kehadiran tetangganya tumbuhan juga menghasilkan senyawa glukosinolat yang jumlahnya makin meningkat sejalan dengan tingginya biodiversitas vegetasi. Senyawa ini merupakan senyawa beracun bagi patogen, sehingga tumbuhan yang dibudidayakan dengan pola monokultur menjadi rentan terhadap penyakit. Oleh karena itu agar tanah tetap memiliki kandungan senyawa glukosinolat yang memadai serta tetap memelihara kondisi rhizosfir yang dinamis perlu dilakukan pergiliran tanaman varietas lokal setelah beberapa rotasi tanaman.Abstract. Similar to human, plants also develop a communication system to achieve their prosperity. Plants utilize chemical compounds of their root exudates as the “languange”. Plants are the initiator of communications, since they define the purposes of building communication. Root exudates are released either to attract or to demenish the soil microbes target as an “invitation letter” to some microbes. To build a mycorrhizal association, for examples, plants issue sugars, amino acids and strygolactones to the rhizosphere. Fungi will reply the invitation by secreting flavonoid compounds that determine host-mycorrhizal specifications. The presence of flavonoids is another invitation to rhizobia to establish association in legume rhizosphere. Plants will select attracted bacteria to build the most host-specific rhizobium association by secreting canavanine compounds that are toxic to non-target rhizobia. Occasionally, an error happened in issuing invitation. When plant release strygolactone in a very low dosages, it will be failure to build mycorrhizal associations otherwise pathogen colonizations, although plants produce either phytoantisipine to prevent pathogens infection or phytoalexin to counter infected pathogens. Communication among roots of neighboring plants is conducted by producing allellopathy compound to limit root growth of the competitors. Invasive plants or weeds generally also produce catechine compounds over the allellophaty that will eliminate soil beneficial microbes of the indigenous plants. As a result, the native plants will be vulnerable to disease and lead to distinct. Responding to the presence of neighboring roots, plants also produce glucosinolate compounds. Glucocynolate consentration will be increased in line with the richness of vegetation biodiversity. These compounds are toxic to the pathogen, which is why plants cultivated in monoculture become more susceptible to disease. Furthermore, to improve soil glucocynolate and to manage the dynamics in the rhizosphere, need to a shift cultivation after several rotations of a commodity with the local varieties

INTERVENSI MANUSIA TERHADAP KOMUNITAS RHIZOSFIR: REVIEW (Human Disturbance on Rhizosphere Communities: Review)

AbstrakWalaupun tersembunyi di dalam tanah komunitas rhizosfir merupakan penentu kehidupan di muka bumi dan berperan penting pada pelestarian alam. Rhizosfir merupakan daerah di sekitar perakaran tanaman yang dihuni oleh berbagai mikrobia tanah yang berperan dalam menentukan pertumbuhan dan kesehatan tanaman. Struktur dan komposisi komunitas mikrobia sangat dipengaruhi oleh macam, konsentrasi dan komposisi eksudat akar. Perubahan yang terjadi pada tanaman (umumnya sangat dipengaruhi oleh aktivitas manusia) mempengaruhi komunitas rhizosfir, sebaliknya komunitas rhizosfir akan menentukan struktur tumbuhan dan fungsi ekosistem. Review ini membahas pengaruh aktivitas manusia yang mempengaruhi kualitas lingkungan terhadap komunitas mikrobia di rhizosfir, yang merupakan hasil kajian dari berbagai sumber terbaru yang dianalisis secara induktif. Aktivitas manusia yang dikaji meliputi praktek pertanian intensif, deforestasi hutan menjadi perkebunan serta perubahan iklim. Hasil kajian menunjukkan bahwa praktek monokulturisasi telah menurunkan biodiversitas mikrobia rhizosfir, menurunkan kinerja enzim tanah dan menurunkan keragaman dan konsentrasi senyawa glukosinolat untuk melawan patogen. Pengolahan tanah, pemupukan anorganik dan penggunaan pestisida telah menurunkan biodiversitas mikrobia rhizosfir. Sebaliknya pemupukan organik tidak berpengaruh terhadap biodiversitas mikrobia tanah. Perubahan fungsi hutan menjadi kebun intensif telah merubah dominansi kelompok mikrobia serta kemampuan mikrobia sesuai fungsinya di ekosistem. Perubahan iklim berdampak pada peningkatan suhu tanah, hal ini telah mengubah komposisi mikrobia rhizosfir. Perubahan komposisi, dominansi dan kemampuan mikrobia di rhizosfir tersebut dapat merubah komposisi populasi tumbuhan di atasnya. Hal ini dapat mengubah keseimbangan dan fungsi ekosistem yang berakibat pada berubahnya kesejahteraan manusia.AbstractEven though it is hidden underground, rhizosphere communities define the life in this earth planet and has an important role on nature preservation. Rhizosphere is the zone of soil adjacent immediately to plant roots which inhabited by varies species of beneficial soil microbes for facilitating plants growth and health. Human activities are strongly influence on plant performance. Alteration on plant growth and health statues determine rhizosphere communities that will define the vegetation structures and ultimately ecosystem functions. This paper discuss the negative influences of human activities (anthropogenic factors) on the environment to the rhizosphere communities. Especially the impacts of intensive farming, deforestation and climate changes. It is sourced from current referrences in inductive analysis. One of intensive farming management is monoculture that is not only drastically depleted microbes diversity in the rhizosphere hence decresed soil enzimes activities, but also reduced glucocynolates production, a crucial compound against pathogen. Whereas, tillage, fertilizers and pesticide application significantly diminished microbe biodiversity. Organic fertilizers, on the other hand, did not give crucial impacts this biodiversity. Modify forest into estate have changed domination of groups and lessened capability of phosphate solubilizers. While climate changes, that enhance soil temperature escalation, have altered rhizosphere microbes composition and structure. Replacement of composition, domination, abundance and capability of rhizosphere communities will modify composition and structure of vegetation aboveground. Eventually, will alter the ballance and functions of the ecosystem, which determine the wealth of human population in the earth

Memahami Komunikasi Tumbuhan-Tanah dalam Areal Rhizosfir untuk Optimasi Pengelolaan Lahan

. Similar to human, plants also develop a communication system to achieve their prosperity. Plants utilize chemical compounds of their root exudates as the “languange”. Plants are the initiator of communications, since they define the purposes of building communication. Root exudates are released either to attract or to demenish the soil microbes target as an “invitation letter” to some microbes. To build a mycorrhizal association, for examples, plants issue sugars, amino acids and strygolactones to the rhizosphere. Fungi will reply the invitation by secreting flavonoid compounds that determine host-mycorrhizal specifications. The presence of flavonoids is another invitation to rhizobia to establish association in legume rhizosphere. Plants will select attracted bacteria to build the most host-specific rhizobium association by secreting canavanine compounds that are toxic to non-target rhizobia. Occasionally, an error happened in issuing invitation. When plant release strygolactone in a very low dosages, it will be failure to build mycorrhizal associations otherwise pathogen colonizations, although plants produce either phytoantisipine to prevent pathogens infection or phytoalexin to counter infected pathogens. Communication among roots of neighboring plants is conducted by producing allellopathy compound to limit root growth of the competitors. Invasive plants or weeds generally also produce catechine compounds over the allellophaty that will eliminate soil beneficial microbes of the indigenous plants. As a result, the native plants will be vulnerable to disease and lead to distinct. Responding to the presence of neighboring roots, plants also produce glucosinolate compounds. Glucocynolate consentration will be increased in line with the richness of vegetation biodiversity. These compounds are toxic to the pathogen, which is why plants cultivated in monoculture become more susceptible to disease. Furthermore, to improve soil glucocynolate and to manage the dynamics in the rhizosphere, need to a shift cultivation after several rotations of a commodity with the local varieties

The Dynamic of Functional Microbes Community Under Auri (Acacia auriculiformis Cunn. Ex Benth) Agroforestry System

Microbes are important rhizosphere constituents for providing nutrients in the soil. This study analyzes the dynamic of soil functional microbes’ populations on land managed as an agroforestry (AF) system. The AF system consists of a 2-years old auri tree combined with several crops, i.e., wild grasses, peanuts (Arachis hypogaea), pigeon pea (Cajanus cajan), and maize (Zea mays). Soil samples were collected from each rhizosphere and then analyzed for their chemical properties such as N, P, K, pH, and C organic contents. The population of functional microbes was observed by isolation of the non-symbiotic N-fixer microbes (BNF), the cellulose-degrading microbes (CDM), and the phosphate solubilizing microbes (PSM) in their selective media. The total soil sugars were also tested for root exudates. The results showed that in an auri agroforestry system, the kind of crops determines the content of the soil organic material that is turned-offer into the soil. This affects the population structure and functional microbial abundance in the rhizosphere. Furthermore, microbial colonization in the rhizosphere affects plants in producing root exudates. Then, root exudates shape the structures of the microbial community, as well as an influence among inhabitants in defining mineralization of soil organic matter, nutrient availability, and trees performance. &nbsp

Isolation, Carriers Selection and Inoculum Formulation of Thiobacillus spp.

One of problems in international trading of coal is high content of suljur. B iodesuljuration of coal using Thiobacillusspp is recognized as the most environmentally friendly to reduce the content. This research was aimed to collect and to isolateThiobacillus spp from coal, acid mine drainage, ex-coal mining soil and agriculture soil, on selected media. Colonies growingon the media were re-isolated for further characterization to find the most similar to Thiobacillus spp. In this experiment, the selected isolate (5, J 0, 20, 50, and J 00 ml) was cultured in 100 g of coal dust, rice husk charcoal, wood charcoal, andactivated charcoal, to find an appropriate inoculum for coal desulJuration. To observe their survival rate, they were reisolated onto 10 ml Thiobacillus broth medium. The re-isolations were observed at the 7, 14, 21 and 28 days of incubation. The results showed that ThiobaciIlus spp was found only in acid mine drainage. After characterization, the isolates were strongly similar to Thiobacillusferrooxidans. The most proper inoculum was 100 ml culture ofThiobacillus in 100 g rice husk charcoal. It had 100% survival rate after 20 days cultured in that carrier

Dampak Penggunaan Insektisida Karbofuran Terhadap Cendawan Ektomikoriza Pisolithus Arrhizus dan Scleroderma columnare yang Diinokulasi Pada Bibit Pinus merkusii Jung Et De Vries (Impact of Use of Carbofuran Insecticide on Ectomychorizal Fungi Pisolithus Arrhizus and Scleroderma columnare Inoculated on Pinus merkusii Seedlings Jung Et De Vries)

Ectomychoriza fungi were selected as one of the most environmentally friendly fertilizers because they have no negative impact on the ecosystem. The inoculation of the fungus increased the total dry weight significantly, but did not affect the proportion of the roots of the Jungus seeds of Jung et de Vries at the age of six months. The use of carbofuran insecticide with fungi has a significant negative impact. In vitro tests show that this fungus can not grow in a culture containing 1 ppm of the material. With the addition of 5 grams of furadan on polybags reduces total dry weight. The mixtures of the fungi S. columnare and P. arrhizus are respectively highly tolerant and less tolerant of carbofuran toxicity

Studi Biodegradasi Karbofuran Oleh Pseudomonas sp. (Studi of The Carbofuran Biodegradation by Pseudomonas sp.)

Carbofuran is one of the pesticides with large spectrum (action in many hosts and kill off many pests), high toxicity to mammals, recalcitrant and tend to build the “soil-bunded residues”. Application of this compound for a long time may cause hazard tothe environment. An effort to manage the pollutin problem is by using of this compound as sole carbon, nitrogen and energy sources. The degradation process took 5 weeks with the efficiency values 68%

Isolasi Bakteri Pereduksi Sulfat Untuk Memperbaiki Sifat Kimia Tanah Bekas Tambang Batubara Dan Pengaruhnya Terhadap Karet (Hevea Brasiliensis) Di Polibeg

Teknik pertambangan terbuka pada lahan bekas tambang batubara di Sumatera Barat mengakibatkan vegetasi penutup tanah hilang, pemadatan tanah, kahat unsur hara, reaksi masam, top soil tipis, rendah bahan organik, tekstur tanah buruk, toksisitas mineral, kandungan logam tinggi dan mengganggu aktivitas mikroorganisme tanah. Mikroba tanah seperti Bakteri Pereduksi Sulfat (BPS) dapat dimanfaatkan untuk perbaikan sifat kimia tanah dalam mendukung revegetasi lahan bekas tambang batubara. Tujuan penelitian adalah untuk mendapatkan isolat BPS dan pengaruhnya terhadap sifat kimia tanah bekas tambang batubara, serta pertumbuhan karet di polibeg. Penelitan ini dilakukan di Balai Penelitian Sungei Putih yang berlangsung bulan Maret-Desember 2015. Sumber isolat BPS yang digunakan berasal dari sewage sludge, sludge industri kertas dan rumen sapi. Isolat yang didapatkan tersebut selanjutnya dimurnikan dan diapilkasikan ke media polibeg. Berdasarkan penelitian didapatkan tiga jenis isolat BPS yaitu isolat A, isolat B, dan isolat D. Semua isolat BPS dapat menurunkan pH, C-organik, dan kandungan sulfat tanah bekas tambang batubara. Pertambahan tinggi tanaman di polibeg setelah tiga bulan aplikasi, semua isolat nyata lebih besar dibandingkan dengan kontrol (tanpa isolat dan hanya media bekas tanah tambang saja)