scholarly journals Study of Root Exudate Organic Acids and Microbial Population in the Rhizosphere of Oil Palm Seedling

2017 ◽  
Vol 22 (1) ◽  
pp. 29-36
Author(s):  
. Anandyawati ◽  
Enok Sumarsih ◽  
Budi Nugroho ◽  
Rahayu Widyastuti

Mutual interaction between plants and microbes occured in the rhizosphere is expected to increase productivity of crops or soil fertility for agriculture. Plants excrete root exudates to attract microbes, and then microbes obtain habitat and food supply from plants and can fulfill the nutrient requirements through assisted enzymatic activity.  The objective of the research was to study the types and amounts of root exudate organic acids, microbial population, and the relationship between root exudate organic acids and microbial population in the rhizosphere of oil palm seedlings. The study was conducted in a greenhouse using a planting medium of sterile quartz sand. The study was conducted using two factorials completely randomized design with three replications. The first factor was oil palm seedling age (control / no oil palm seed, 1, 3, 6, 9 and 12 months-old of oil palm seedlings) and the second factor was the periods of seedling growth (45, 90, 135 and 180 days), so in total there were 72 experimental units. The result of High Pressure Liquid Chromatography (HPLC) analysis revealed that four kinds of organic acids were observed in the rhizosphere of oil palm seedlings, with the highest concentration were: acetic acid (1.66 ppm), citric acid (0.157 ppm), malic acid (2.061 ppm) and oxalic acid (0.675) ppm. The highest total population of microbes, fungi, Azotobacter, phosphate solubilizing bacteria (PSB) and phosphate solubilizing fungi (PSF) were 19.38 × 106 cfu g-1 soil, 3.28 × 104 cfu g-1 soil, 12.09 × 105 cfu g-1 soil, 8.39 × 104 cfu g-1 soil and 1.15 × 104 cfu g-1 soil, respectively. There are positive correlations between root exudate organic acids and total microbes, fungi, Azotobacter, PSB and PSF are.Keywords: microbes, organic acids, rhizosphere, root exudates

Chemosphere ◽  
2020 ◽  
Vol 244 ◽  
pp. 125475 ◽  
Author(s):  
Wan-Li Li ◽  
Jun-Feng Wang ◽  
Yao Lv ◽  
Hao-Jie Dong ◽  
Li-Li Wang ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Mahreen Yahya ◽  
Ejaz ul Islam ◽  
Maria Rasul ◽  
Iqra Farooq ◽  
Naima Mahreen ◽  
...  

Phosphorous (P) deficiency is a major challenge faced by global agriculture. Phosphate-solubilizing bacteria (PSB) provide a sustainable approach to supply available phosphates to plants with improved crop productivity through synergistic interaction with plant roots. The present study demonstrates an insight into this synergistic P-solubilizing mechanism of PSB isolated from rhizosphere soils of major wheat-growing agro-ecological zones of Pakistan. Seven isolates were the efficient P solubilizers based on in vitro P-solubilizing activity (233-365 μg ml–1) with a concomitant decrease in pH (up to 3.5) by the production of organic acids, predominantly acetic acid (∼182 μg ml–1) and gluconic acid (∼117 μg ml–1). Amplification and phylogenetic analysis of gcd, pqqE, and phy genes of Enterobacter sp. ZW32, Ochrobactrum sp. SSR, and Pantoea sp. S1 showed the potential of these PSB to release orthophosphate from recalcitrant forms of phosphorus. Principal component analysis indicates the inoculation response of PSB consortia on the differential composition of root exudation (amino acids, sugars, and organic acids) with subsequently modified root architecture of three wheat varieties grown hydroponically. Rhizoscanning showed a significant increase in root parameters, i.e., root tips, diameter, and surface area of PSB-inoculated plants as compared to uninoculated controls. Efficiency of PSB consortia was validated by significant increase in plant P and oxidative stress management under P-deficient conditions. Reactive oxygen species (ROS)-induced oxidative damages mainly indicated by elevated levels of malondialdehyde (MDA) and H2O2 contents were significantly reduced in inoculated plants by the production of antioxidant enzymes, i.e., superoxide dismutase, catalase, and peroxidase. Furthermore, the inoculation response of these PSB on respective wheat varieties grown in native soils under greenhouse conditions was positively correlated with improved plant growth and soil P contents. Additionally, grain yield (8%) and seed P (14%) were significantly increased in inoculated wheat plants with 20% reduced application of diammonium phosphate (DAP) fertilizer under net house conditions. Thus, PSB capable of such synergistic strategies can confer P biofortification in wheat by modulating root morphophysiology and root exudation and can alleviate oxidative stress under P deficit conditions.


2019 ◽  
Vol 20 (11) ◽  
Author(s):  
Dermiyati Dermiyati ◽  
Radix Suharjo ◽  
Mareli Telaumbanua ◽  
Yeyen Ilmiasari ◽  
Rully Yosita ◽  
...  

Abstract. Dermiyati, Suharjo R, Telaumbanua M, Ilmiasari Y, Yosita R, Annisa RM, Sari AW, Andayani AP, Yulianti DM. 2019. Population of phosphate solubilizing bacteria in the liquid organic fertilizer created from palm oil bunches and pineapple rhizome. Biodiversitas 20: 3315-3321. Palm oil bunches and pineapple rhizomes are abundant in Indonesia, especially in Lampung Province due to widespread agro-industrial company and they are potential to be used as sources for liquid organic fertilizer. This study was aimed to reveal microbial population within liquid organic fertilizer (LF) which was developed from palm oil bunches (PB) and pineapple rhizome (PR) and their role as phosphate solubilizing bacteria (PSB). The capability to solubilize phosphate was recorded from the clear zone area around the bacterial colony which was cultivated on Pikovskaya’s agar medium. The LF was prepared in three kinds of conditions, namely aerobic, anaerobic, and facultative an aerobic. Isolation was performed every 3 days until 24 days after incubations. The results showed that microbial population in the LF from PR was significantly higher than those developed from PB. Totally, 791 bacterial isolates were obtained from the LF; 490 isolates were achieved from PR (153 isolates from aerobic, 188 isolates from facultative anaerobic, 149 from anaerobic conditions) and 301 isolates were collected from PB (96 isolates from aerobic, 112 isolates from facultative anaerobic, 93 isolates from anaerobic conditions). In the case of isolates that were gained from PB, 166 isolates (55.15%) showed capability to degrade phosphate and 135 isolates (44.85%) did not show any capability as PSB. As for isolates obtained from PR, 269 isolates (54.90%) had capability to solubilize phosphate, meanwhile, the other 221 isolates (45.10%) did not show any capability to solubilize phosphate. Among166 isolates of PSB from PB, 60 isolates had very low capability, 55 isolates had low capability, 34 isolates had medium capability, 10 isolates had high capability and only 7 isolates had very high capability. Meanwhile, from 269 isolates of PSB obtained from PR, 135 isolates had very low capability to solubilize phosphate, 84 isolates had low capability to solubilize phosphate, 32 had medium capability to solubilize phosphate, 14 isolates had high capability to solubilize phosphate and 4 isolates produced very high capability as PSB. In total, 11 chosen isolates were selected from LF developed from both PB (7 isolates) and PR (4 isolates). Therefore, palm oil bunches and pineapple rhizomes contained PSB that can be used as LF.


2020 ◽  
Vol 11 ◽  
Author(s):  
Luciana F. Brito ◽  
Marina Gil López ◽  
Lucas Straube ◽  
Luciane M. P. Passaglia ◽  
Volker F. Wendisch

Due to the importance of phosphorus (P) in agriculture, crop inoculation with phosphate-solubilizing bacteria is a relevant subject of study. Paenibacillus sonchi genomovar Riograndensis SBR5 is a promising candidate for crop inoculation, as it can fix nitrogen and excrete ammonium at a remarkably high rate. However, its trait of phosphate solubilization (PS) has not yet been studied in detail. Here, differential gene expression and functional analyses were performed to characterize PS in this bacterium. SBR5 was cultivated with two distinct P sources: NaH2PO4 as soluble phosphate source (SPi) and hydroxyapatite as insoluble phosphate source (IPi). Total RNA of SBR5 cultivated in those two conditions was isolated and sequenced, and bacterial growth and product formation were monitored. In the IPi medium, the expression of 68 genes was upregulated, whereas 100 genes were downregulated. Among those, genes involved in carbon metabolism, including those coding for subunits of 2-oxoglutarate dehydrogenase, were identified. Quantitation of organic acids showed that the production of tricarboxylic acid cycle-derived organic acids was reduced in IPi condition, whereas acetate and gluconate were overproduced. Increased concentrations of proline, trehalose, and glycine betaine revealed active osmoprotection during growth in IPi. The cultivation with hydroxyapatite also caused the reduction in the motility of SBR5 cells as a response to Pi depletion at the beginning of its growth. SBR5 was able to solubilize hydroxyapatite, which suggests that this organism is a promising phosphate-solubilizing bacterium. Our findings are the initial step in the elucidation of the PS process in P. sonchi SBR5 and will be a valuable groundwork for further studies of this organism as a plant growth-promoting rhizobacterium.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Guan-Xi Li ◽  
Xiao-Qin Wu ◽  
Jian-Ren Ye ◽  
He-Chuan Yang

The objective of this study was to investigate whether plant-bacteria interaction affects the secretion of organic acids by both organisms and to assess whether the production of IAA by the bacterium increases the secretion of organic acids by root exudates, and if the stress produced by low available phosphorus (P) affects the production of organic acids by bacteria, by roots, or by root exudates in presence of bacterial cultures. With this purpose, we used as a biological model poplar plants and one strain ofBurkholderia multivoransable to solubilize P. High performance liquid chromatography was utilized to measure organic acids. The tests, the inductive effects of exogenous indole-3-acetic acid (IAA) on secretion of organic acids, the 2 × 4 × 2 factorial design experiment, and the ability of organic acids to solubilize tricalcium phosphate were performed to investigate the interactive effects. The results showed that, afterB. multivoransWS-FJ9 interacted with the poplar root system, the key phosphate-solubilizing driving force was gluconic acid (GA) which was produced in three ways: (1) secreted by the root system in the presence of IAA produced byB. multivoransWS-FJ9; (2) secreted byB. multivoransWS-FJ9; and (3) secreted by the poplar root system in the presence of phosphorus stress. When phosphorus stress was absent, the GA was produced as outlined in (1) and (2) above. These results demonstrated that inoculatingB. multivoransWS-FJ9 into the poplar root system could increase the amount of GA secretion and implied that the interaction betweenB. multivoransWS-FJ9 and the poplar root system could contribute to the increase of P available fraction for poplar plants.


2018 ◽  
Vol 4 (01) ◽  
pp. 70-75
Author(s):  
Ratul Baishya ◽  
Rhituporna Saikia

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.


2018 ◽  
Vol 13 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Tri Candra Setiawati ◽  
Paniman Asna Mihardja

Phosphate solubilizing bacteria (PSB) metabolites are organic acids, phosphomonoesterase enzyme (alkaline phosphatase) and antibiotic, which is able to dissolve insoluble phosphate. Phosphate solubilizing bacteria used in this study was expected to suppress Rhizoctonia solani attacks. This experiment was aimed at (1)  identifiying and quantifying  PSB metabolites, and (2) examining their capability as biocontrol agent for Rhizoctonia solani in vitro and hydroponics soybean. This study was conducted in three stages. The first stage of this study was culturing two PSB isolates (Pseudomonas putida 27.4B and Pseudomonas diminuta) in the Pikovskaya medium to analyze their metabolites. The second and third stage of this study was testing the antagonist of two bacteria to suppressed R. solani activity, which was conducted in vitro, and in hydroponics medium soybean as indicator plant. The results showed that P. putida 27.4B and P. diminuta produced organic acids i.e.: citrate, formic, succinic, acetic, propionate, butyrate, and oxalate. The totals of organic acids from each bacterium were 70,3 mg.kg-1 and 61,9 mg.kg-1. Production of alkaline phosphatase enzyme in Pikovskaya medium of P. Putida27.4B was 11,71 μg pNP .mL-1.h-1 and P. diminuta was 24,04  μg pNP.mL-1.h-1. Concentration of this enzyme in soil medium was higher than that in Pikovskaya medium with 26,27 μg pNP.g-1.h-1 and 39,03 μg pNP.g-1.h-1 respectively. This study also showed that total concentration of antibiotics (tetracycline, oxitetracycline and penicillin) produced by the PSB, were 3,2 μg.mL-1 (P. putida 27.4B) and 10,96 μg.m1-1 (P. diminuta), respectively. The results from second stage of this study showed that by using in vitro, the reduced growth of  R. solani was observed 58,35% with P. putida 27.4B and 41,96% with P. diminuta. In addition, inoculations of PSB in hydroponics medium reduced the fungal pathogenesis from 10,71% to 21,42% of pre and post emergence damping-off. Visually, the symptom of pathogen attack appeared within the period of  2 untill 14 days after infection.


2020 ◽  
Vol 4 (2) ◽  
pp. 59
Author(s):  
Pauliz Budi Hastuti ◽  
Sri Manu Rohmiyati

<p>This research aimed to evaluate the effect of empty fruit bunches (efb) compost, phosphate-solubilizing bacteria (PSB), lime, and types of P fertilizer on the growth and availability of Phosphorus and P uptake in the pre-nursery (PN) oil palm seedlings in latosols. The pot experiments were arranged in a Factorial Completely Randomized method. The first factor was the application of efb compost: without efb compost, efb compost, without efb compost + PSB, and without efb compost + lime. The second factor was the types of P fertilizer: SP-36, RP, guano, and NPKMg + Urea as a control. The results showed that the combination of without efb compost +lime and RP fertilizer produces the highest number of leaves. The influence of a single factor showed that the application of without efb, efb compost, without efb compost +PSB, without efb compost + lime, resulted in the same growth of seedlings, except on plant height and the length of the leaf. The various types of P fertilizer led to the same growth of seedlings except for stem diameter. The highest available P was obtained in the combination of without efb compost + PSB with SP-36 fertilizer, which was 631.1% compared to control (without efb compost and NPKMg, Urea) and the lowest in the combination of without efb compost + lime with (NPKMg, Urea). The treatment without efb compost + lime with SP-36 fertilizer increased P uptake of leaves by 55.6% and stem by 47.1% compared to control.</p>


2015 ◽  
Vol 6 (1) ◽  
pp. 37
Author(s):  
Fahrizal Hazra

<p>ABSTRACT</p><p>Snake fruit [Salacca zalacca (Gaertner) Voss] Pondoh is one of important fruits in Indonesia. The objective of the study was to determine the  influence of some selected potential microbes such as Phosphate Solubilizing Bacteria, Cellulolytic Bacteria, and  N2-fixing Bacteria (Azospirillum)  ongrowth of seedling  of  snake  fruit  Pondoh.  A  study  was  conducted  in  the nursery. The  experiment used  a  completely  randomized  design  with  treatments namely:  K0  (without  inoculum);  A1 (Azospirillum inoculum dose 5 ml), A2 (inoculum 25 ml); F1 (BPF inoculum dose 5 ml), F2 (dose 25 ml); S1; BPS inoculums (dose 5 ml), S2 (dose 25 ml); C1 (mixed bacterial inoculum A+F+S dose 5 ml), and C2 (A+F+S dose 25 ml). Plant height, P, C/N soil ratio, N were measured in 10 months for observing the impact of treatments. Results showed that the effect of inoculation of A2 to the amount of  N-total  (0.99%)  was significantly  different  compared  to  soil  with  K0;  and  not significantly different  from  the  amount  of  N-total  inoculation  A1,  F1,  F2, S1,  S2,  C1,  and  C2.  F2  increased availability of P (20.79 ppm) in the soil higher than  K0, A1, F1; and not significantly different from A2, S1, S2, C1, and C2.  K0 treatment gave  C/N ratio of soil significantly different from A1, A2, F1, F2, S1, S2, C1 and C2; BPS which showed activity in overhauling C-organic in the soil. Inoculation A2  and F2  increased  plant  height  15.48% and 9.31%  higher  than  the  control.  Inoculation  of  C2 differed  significantly  in improving  the  fresh  weight  compared  to  control;  and  not significantly different  from  A1,  A2,  F1,  F2,  S1,  S2,  and  C1  and  able  to increase  the  dry  weight  of  71.12% compared to the control.</p><p>Keywords: Azospirillum, Cellulolytic Bacteria, Phosphate Solubilizing Bacteria, Snake Fruit</p><p> </p><p>ABSTRAK</p><p>Salak Pondoh [Salacca zalacca (Gaertner) Voss] merupakan tanaman buah bernilai tinggi dan diminati  masyarakat.  Budidaya  salak  diawali  dengan pembibitan.  Penelitian  ini  bertujuan  menguji pengaruh  bakteri  potensial hasil  isolasi  dan  seleksi  dari  bakteri  pelarut  fosfat  (BPF), bakteri perombak  selulosa  (BPS),  dan  bakteri  pemfiksasi  N2  (Azospirillum) dalam  pertumbuhan  bibit tanaman  salak pondoh. Penelitian ini menggunakan rancangan acak lengkap satu faktor yang terdiri atas: K0 (tanpa inokulum/Kontrol);  A1  (inokulum  Azospirillum  5  ml), A2 (25  ml inokulum);  F1 (inokulum BPF dosis 5 ml), F2 (dosis 25 ml); S1 (inokulum BPS dosis 5  ml), S2 (dosis 25 ml); C1 (inokulum campuran A+F+S dosis 5 ml), dan C2 (dosis 25 ml).  Pengamatan dilakukan selama 10 minggu  sampai  bibit salak  Pondoh  memiliki dua daun.  Hasil penelitian menunjukkan  inokulasi A2dan S2  nyata  jumlah N-total (0.99%) di dalam tanah dibandingkan  dengan K0; tetapi  tidak berbeda nyata dibandingkan dengan perlakuan lain. Inokulasi F2 nyata meningkatkan P tersedia (20.79 ppm) di dalam tanah dibandingkan dengan K0, A1, F1; dan tidak berbeda nyata dengan A2, S1, S2, C1, dan C2. Induksi dengan seluruh isolat nyata terhadap C/N rasio tanah; yang menunjukkan adanya aktivitas BPS dalam  merombak C-organik  di dalam tanah.  Inokulasi  A2  dan  F2  mampu meningkatkan tinggi tanaman 9.31% dan 15.48% lebih  besar  dibandingkan kontrol. Inokulasi C2 nyata meningkatkan bobot basah bibit salak pondoh dibandingkan kontrol; tetapi tidak berbeda nyata dengan perlakuan lain serta mampu meningkatkan bobot kering 71.12% dibandingkan kontrol.</p><p>Kata kunci: Azospirillum, bakteri pelarut fosfat, bakteri perombak selulosa, Salak Pondoh</p>


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