scholarly journals The assimilation of nitrogen by certain nitrogen-fixing bacteria in the soil

In a communication on “Some Effects of Nitrogen-fixing Bacteria on the Growth of Non-Leguminous Plants,” it was pointed out that Azotobcider and Pseudomonas obtained from the root tubercles of Cycas when grown together fix more nitrogen per unit of carbohydrate than the combined amount of nitrogen when each is grown separately. In order to determine if this is true for a mixed culture of Azotobacter and Pseudomonas obtained from ordinary soil and leguminous nodules respectively, pure cultures of these organisms were obtained, Azotobacter and chroocoecm from garden soil and Pseudomonas radicicola from bean and clover nodules, by the method already described. Erlenmeyer flasks containing a culture solution, consisting of maltose 0·5 gramme, mannite 0·5 gramme, monobasic potassium phosphate 0·1 gramme, magnesium sulphate 0·02 gramme, in 100 c.c. distilled water and rendered neutral by sodium hydrate, were inoculated with 1 c.c. of pure cultures per 100 c.c. of culture solution (the controls being autoclaved to kill the bacteria present), and incubated at 24° C. for 10 days. Nitrogen determinations of the contents of the flasks gave the following averages:- Gerlaeh, Lipman, and others have described experiments showing that pure cultures of Azotobader and Pseudomonas respectively have little or no power to increase the store of soil nitrogen when added directly to the soil. A probable explanation of these negative results may be found in the different conditions for growth and development in ordinary soil and in a culture solution.

2021 ◽  
Vol 255 ◽  
pp. 01006
Author(s):  
Serhii Dymytrov ◽  
Vasil Sabluk ◽  
Semen Tanchyk ◽  
Mykhailo Gumentyk ◽  
Oleg Balagura

The aim is to study how presowing usage of biologies Mycofriend, Mikovital and Florobacillin influences on biometric indicators of maize, its productivity and soil moisture holding capacity. Using mycorrhizal fungi and nitrogen-fixing bacteria, we have received positive results about their influence on plant growth and development and maize yield forming. Leaf surface area in variants with fungi Trichoderma harzianum Rifai (Mycofriend bio-based product), and Tuber melanosporum Vittad (Mikovital bio-based product) and bacteria Bacillus subtilis Cohn. (Florobacillin bio-based product) was counted on 30th, 60th, 90th and 120th days of vegetation and was estimated by 11.2–90.0% higher compared to the control. Leaf mass and root system mass exceeded control indicators by 24.0–48.9%, respectively. Plants height in these accounted periods was higher by 4.0–31.5% compared to the control. In addition, in these variants, soil moisture holding capacity increased by 7.3–38.1%, share of soil lumps smaller than 0.25 mm decreased by 2.8–7.2%. Grain yield of Maize in variants with mycorrhizal fungi and nitrogen-fixing bacteria was 1.64–2.68 t/ha higher than in the control. It should be noted that presowing usage of fungus Trichoderma harzianum Rifai on plants seeds, provides better efficiency on plants’ growth and development and their productivity.


Author(s):  
С. М. Крамарьов ◽  
С. Ф. Артеменко ◽  
П. В. Писаренко

Інокуляція та інкрустація насіння в технології ви-рощування кожної культури займає важливе значен-ня. Обробка посівного матеріалу перспективнимиштамами азотфіксуючих бактерій позитивно впли-нула на потенціал продуктивності азотфіксації соїй, як наслідок, на врожай даної культури. На ділян-ках, де насіння за інокуляції було оброблено штамами46 та 626а кількість бульбочок на одній рослині зрос-ла в 3,3 разу, а їх маса вдвічі. Ці посіви формувалимаксимальну площу листя (39,0–40,0 тис. м2/га), щоперевищувала контрольні ділянки на 17,8–20,8 %.Кількість бобів зросла на 11,7–17,4 %. Передпосівнаінокуляція насіння азотфіксуючими штамами буль-бочкових бактерій Х9; 626а; 46 забезпечила кращіумови для азотфіксації та досить високу насіннєвупродуктивність сої. Урожайність насіння сої, депроводили передпосівну обробку насіння перспектив-ними штамами бульбочкових бактерій, зросла на11,9–15,2 %. Проведення інкрустації насіннєвого ма-теріалу сої плівкоутворювачем Марс ЕL та препа-ратом Антистрес, що містить калій фосфорнокис-лий разом із молібденом та бором, сприяла підвищен-ню польової схожості на 10,8–11,8 %. Використанняцих препаратів забезпечило формування більшої ви-соти рослин сої на 9,6–14,2 %, а кількість азотфік-суючих бульбочок зросла на 26,3–39,5 %. Посіви соїформували більшу площу асиміляційної листковоїповерхні на 26,7 % за інкрустації насіння з використан-ням препарату антистрес, а сумісно з комплексонатамиметалів молібдену і бору цей показник зростав до 53,5 %.Найкращий врожай насіння (2,18 т/га), формували по-сіви сої з використанням для інкрустації посівногоматеріалу препарату антистрес (200 г/т) і комплек-сонатів металів молібдену й бору (100 г/т кожного)та протруйника гранівіт (2,5 л/т). Inoculation and incrustation of seeds in technology every culture is important. Treatment of inoculum promising strains of nitrogen-fixing bacteria positive influence on the potential productivity of nitrogen fixation and consequently the harvest of this crop. On the plots, where the seeds of inoculation were treated strains 46 and a, the number of nodules on the same plant grew 3.3 times, and their weight in 2 times. These crops are formed maximum area leaves 39,0-40,0 thousand m2/ha)that was beyond the control plots 17.8-20,8%. The number of beans increased by 11.7-17,4%. Pre-sowing seed inoculation azotfiksatsii strains of root nodule bacteria X9; a; 46 have provided the best conditions for nitrogen fixation and high seed productivity of soy. The yield of soybean seeds, which produced the pre-sowing treatment of seeds per-looking strains of nitrogen-fixing bacteria, increased by 11.9 15.2%. Incrustation of seeds with foaming agent Mars EL and drug Antistress, which contains potassium phosphate, together with molybdenum and boron put additional field germination rate is 10.8-11.8 percent. The use of these drugs was provided by the formation of a greater height of soybean 9.6-14.2%and the number of nitrogen-fixing nodules increased by 26.3-39,5%. Soybean crops have formed a large area of assimilating leaf surface by 26.7% with the use of the drug antistress at the incrustation of seeds, and together with complexions metals molybdenum and boron this figure increased to 53.5%. The best yield of 2.18 t/ha, formed soybean crops using for incrustation of inoculum preparation Antistress (200 g/t) of complexions and metals molybdenum and boron (100 g/t each) and the crickets granilit (2.5 l/t).


1983 ◽  
Vol 29 (8) ◽  
pp. 863-866 ◽  
Author(s):  
N. S. Subba Rao

Rhizosphere soil of several plantation and orchard plants were analyzed to enumerate and isolate Azotobacter and Beijerinckia. Azospirillum was isolated from washed and surface-sterilized roots and 14 of the isolates were classified as A. lipoferum or A. brasilense. The ability of all these bacterial isolates to fix N2 in pure cultures on N-free media was established by Microkjeldahl and C2H2 reduction procedures. Motile bacteria capable of reducing triphenyltetrazolium chloride were found to be more abundant in xylem cells than in cortical cells of roots.


2018 ◽  
Vol 28 ◽  
pp. 33-40
Author(s):  
S.F. Kozar

Objective. Investigate the activity of biosynthesis of phytohormonal substances with nitrogen-fixing bacteria Bradyrhizobium japonicum and Azospirillum brasilense in pure and mixed culture. Methods. Microbiological, chromatographic, and mathematical. Results It has been established that the simultaneous cultivation of B. japonicum M-8 and A. brasilense 410 increases the content of gibberellins and cytokinins in the culture fluid of the test microorganisms. The content of gibberellic acid and isopentenylidene has increased most intensively in mixed culture compared with the pure culture of rhizobia. In the course of co-cultivation, the studied diazotrophs more intensively produced auxins compared to soybean rhizobia in pure culture, but less compared to pure culture of azospirilla. The highest level of abscisic acid that can inhibit the formation of nodules was found in A. brasilense 410 culture fluid, and it was lower when cultivating B japonicum M-8. However, the smallest amount of this phytohormone was found in the culture liquid of diazotrophs under their co-cultivation. The lowest ratio of auxin/cytokinin was found in B. japonicum M-8 and A. brasilense 410 culture fluid under their co-cultivation, which should positively influence the formation of a symbiotic system when interacting with soybean plants. Conclusion. A combination of cultivating rhizobia and azospirilla showed an increase in the amount of cytokinins and gibberellins in the culture fluid of the microorganisms, a decrease in the amount of abscisic acid and improvement in the auxin/cytokinin ratio compared to the values of the pure cultures of the nitrogen-fixing bacteria studied. An analysis of the quantitative parameters of the content of phytohormones suggests the feasibility of combining B. japonicum and A. brasilense in a mixed culture for the effective introduction of rhizobia in soybean agrocenosis.


2021 ◽  
Vol 12 (2) ◽  
pp. 326-334
Author(s):  
A. S. Schogolev ◽  
I. M. Raievska

Nitrogen deficiency is a limiting factor in increasing efficiency of crop production in terrestrial ecosystems, and the transformation of inert nitrogen to forms that can be assimilated by plants is mediated by soil microorganisms. Symbiotic nitrogen-fixing bacteria and roots depend on each other and have developed various mechanisms for symbiotic coexistence. The aim of this work was to investigate the role of nitrogen deficiency on growth and development near isogenic by E genes lines of soybean (Glycine max (L.) Merr.): short-day (SD) line with genotype Е1е2е3(Е4е5Е7), and photoperiodic insensitive (PPI) line with genotype е1е2е3(Е4е5Е7) grown from seeds inoculated with active strains of Bradyrhizobium japonicum against the background of local populations of diazotrophs of the genus Azotobacter spp. and establish how the soybean – Bradyrhizobium symbiosis will develop as the genes of both microsymbionts and macrosymbionts are responsible for the formation of the symbiotic complex. Plants were grown in a vegetation chamber, in sand culture. To assess the quantitative composition of microorganisms in the rhizosphere and rhizoplanes, 6 plants were selected from each soybean line, then separation of the zones of the rhizosphere and rhizoplanes was performed using the method of washing and the resulting suspension was used for inoculation on dense nutrient media (mannitol-yeast agar medium and Ashby medium). The results of study showed that seed inoculation and co-inoculation provides faster formation of the symbiotic soybean – Bradyrhizobium complex. Differences in nodulation rates between the short-day line with genotype Е1е2е3(Е4е5Е7), and a photoperiodic insensitive line with genotype е1е2е3(Е4е5Е7) were identified. Determination of the amount of B. japonicum on the medium of mannitol-yeast agar in the rhizosphere and rhizoplane showed that inoculation by B. japonicum strain 634b caused a significant increase in the amount B. japonicum in the rhizosphere and rhizoplane in both soybean lines, comparison with non-inoculated seeds. Then, co-inoculation by B. japonicum strain 634b + Azotobacter chroococcum significantly increased the amount of B. japonicum only in the rhizoplane and decreased their number in the rhizosphere. Determination of the amount of A. chroococcum on the Ashby elective medium in the rhizosphere and rhizoplane showed that the inoculation by B. japonicum strain 634b caused a significant decrease in the amount of A. chroococcum both in the rhizosphere and in the rhizoplane of the PPI line of soybean, and in the rhizosphere the SD line, in comparison with non-inoculated seeds. That can testify to the competitive interaction of these microorganisms. However, the co-inoculation by B. japonicum strain 634b + A. chroococcum in the SD line significantly increased the number of A. chroococcum in the rhizoplane and decreased their number in the rhizosphere, in the PPI line their number decreased in the rhizoplane and increased in the rhizosphere, in comparison with non-inoculated seeds. Probably, the E genes (their dominant or recessive state) of soybean isogenic lines affect the regulation of the content and distribution of sugars. It was established that the nitrogen deficiency stimulated development of the root system of plants and the synthesized sugars were distributed predominantly to the root system growth. We suppose that the seeds’ inoculation had extended sugar consumption to the symbiont, due to which it compensates the lack of nitrogen, but leads to a slower growth of the root system.


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