Nitrogen Fixation by Nodulated Roots of Viminaria juncea (Schrad. & Wendl.) Hoffmans, (Fabaceae) When Submerged in Water

1983 ◽  
Vol 10 (5) ◽  
pp. 409 ◽  
Author(s):  
BA Walker ◽  
JS Pate ◽  
J Kuo
Keyword(s):  
Dry Matter ◽  
Lateral Roots ◽  
Natural Populations ◽  
Sand Culture ◽  
Total N ◽  
Near Surface ◽  
Plant Parts ◽  
Feeding Experiments ◽  
Rooting Medium ◽  
Assay Chamber

Nodulated seedlings of Viminaria juncea were raised in free-draining or flooded sand culture. Unflooded seedlings developed limited amounts of aerenchyma in lower stem, root and nodules, and responded to flooding by accelerated aerenchyma production and, after 10 days, by formation of pneumatophores from their near-surface lateral roots. Continuously flooded seedlings showed earlier and greater development of aerenchyma and pneumatophores, and had their nodules and roots restricted to the upper 10 cm of the rooting medium. Aerenchyma was developed from an inner cambium, distinct from the outer phellogen which subsequently developed on older parts of stem, root and nodules. Gas contents of plant parts varied from 4-8% for organs with little aerenchyma to over 30% for the aerenchyma-invested basal stem and root of continuously flooded seedlings. A role of the sheaths of aerenchyma in gaseous exchange between aerial environment and nodulated root was demonstrated by gas injection experiments, in situ C2H2 reduction assays and 15N2 feeding experiments on intact plants with flooded roots. Samples of gas removed from the aerenchyma of plants exposed to C2H2 contained up to 14 times the amount of C2H2 and 4 times the amount of CO2 than in the atmosphere of the assay chamber, indicating that gas exchange for both N2 fixation and respiration occurred via the aerenchyma. Previously unflooded, 12-week seedlings exposed to 14 days flooding gained as much dry matter and total N in the 2-week treatment as did control unflooded plants, but 21-week continuously flooded seedlings showed only half the dry matter and nitrogen gains of similarly aged unflooded seedlings. Observations on the seasonal growth, nodulation and pneumatophore development of natural populations of the species were discussed in relation to the above findings.

scholarly journals Accumulation of Macro- and Micronutrients and Nitrogen Demand-supply Relationship of ‘Gala’/‘Malling 26’ Apple Trees Grown in Sand Culture

2009 ◽  
Vol 134 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Lailiang Cheng ◽  
Richard Raba
Keyword(s):  
Dry Matter ◽  
Shoot Growth ◽  
Sand Culture ◽  
Nutrient Accumulation ◽  
Total N ◽  
Supply Relationship ◽  
Macro And Micronutrients ◽  
Relationship Of ◽  
Fruit Harvest ◽  
N Demand

Six-year-old ‘Gala’/‘Malling26’ (‘M.26’) apple (Malus ×domestica Borkh.) trees grown in sand culture were provided with a total of 30 g of N per tree as enriched 15N-NH4NO3 in Hoagland's solution via fertigation to determine the magnitude and seasonal patterns of accumulation of macro- and micronutrients and the demand-supply relationship of N. Crop load was adjusted to 8.2 fruit/cm2 trunk cross-sectional area, at king fruit diameter of 10 mm by hand-thinning. At each of seven key developmental stages throughout one annual growth cycle, four trees were excavated and destructively sampled for complete nutrient analysis. Nutrient concentrations in leaves and fruit fell within the recommended optimal range, and the fruit yield was 18.8 kg/tree (equivalent to 52.45 t·ha−1) with an average fruit weight of 181 g. The net accumulation of N, P, K, Ca, Mg, and S from budbreak to fruit harvest was 19.8, 3.3, 36.0, 14.2, 4.4, and 1.6 g/tree, respectively, and that for B, Zn, Cu, Mn, and Fe was 93.6, 60.9, 46.5, 184.8, and 148.7 mg/tree, respectively. Nutrient accumulation by new growth (fruit plus shoots and leaves) accounted for over 90% of the net gain for N, P, K, Mg, S, and B in the whole tree and a large proportion of the net gain for Ca, Zn, Mn, and Fe (from 58.1% for Zn to 87.2% of Fe) from budbreak to fruit harvest. Differential nutrient accumulation patterns were found in shoots and leaves and fruit. The most rapid accumulation of all nutrients in shoots and leaves took place during active shoot growth from bloom to the end of shoot growth. The accumulation pattern of most nutrients corresponded well with the accumulation of dry matter, with continued accumulation observed only in total Ca and Mn in shoots and leaves after the end of shoot growth. Nutrient accumulation in fruit largely followed its dry matter accumulation, and a large proportion of the nutrient accumulation (from 58.1% for Zn to 77.4% of K) occurred from the end of shoot growth to fruit harvest. At harvest, fruit contained more P, K, B, and Fe, whereas shoots and leaves had more N, Ca, Mg, S, Zn, and Mn. Most of the N demand by new growth at bloom was provided by tree reserve N. Remobilization of N from perennial parts of the tree was found to support rapid fruit expansion from the end of shoot growth to fruit harvest. The most rapid uptake from current season's N supply occurred from bloom to the end of shoot growth, corresponding to the highest tree N demand. At harvest, 62.4% of the total N in new growth was in shoots and leaves, with the balance in fruit. Reserve N and current season's N uptake each contributed about 50% to the total N in the whole tree at harvest.

Assessment of the nitrogen status of field-grown canola (Brassica napus) by plant analysis

1997 ◽  
Vol 37 (1) ◽  
pp. 83 ◽  
Author(s):  
P. J. Hocking ◽  
P. J. Randall ◽  
D. De Marco ◽  
I. Bamforth
Keyword(s):  
Brassica Napus ◽  
Dry Matter ◽  
Stem Elongation ◽  
Dry Weight ◽  
Growth Stages ◽  
Total N ◽  
Plant Parts ◽  
Nitrate N ◽  
Matter Production ◽  
N Status

Summary. Field trials were conducted over 2 seasons at Greenethorpe and Canowindra in the Cowra region of New South Wales to develop and calibrate plant tests for assessing the nitrogen (N) status of canola (Brassica napus). Plants were tested at 3 and 7 growth stages up to the start of flowering at Greenethorpe and Canowindra, respectively. The petiole of the youngest mature leaf (YML) was the most suitable plant part to sample for tests based on nitrate-N. Suitable plant parts for tests based on total N were the YML petiole or lamina, or the whole shoot. There was good agreement between the 2 sites in the just-adequate fertiliser N rates (rates giving 90% of maximum yield) and the critical N concentrations in the plant parts tested. Critical nitrate-N concentrations in the fresh YML petiole for dry matter production at the time of sampling the plants decreased from 1.62 to 0.14 mg nitrate-N/g fresh weight between the 4–5 leaf rosette stage (4–5 RS) and the start of flowering (SF). Critical nitrate-N concentrations in the dry YML petiole decreased from 16.5 to 0.8 mg/g dry weight between 4–5 RS and SF. Critical total N concentrations decreased from 4.5 to 2.0, 7.2 to 5.0 and 6.2 to 2.8% dry weight, in the YML petiole, YML lamina, and whole shoot, respectively, between 4–5 RS and SF. Critical nitrate-N and total N concentrations for assessing potential seed yield were similar to those for dry matter production at the time of sampling for each of the growth stages. The critical total N concentrations obtained for the YML petiole and lamina, and the whole shoot before the start of stem elongation are likely to be less precise than the critical nitrate-N concentrations in the YML petiole because of the limited response of total N concentrations to increasing rates of fertiliser N. However, total N in the YML petiole or lamina, or in the whole shoot may be a better indicator of N status for plants sampled after the start of stem elongation as nitrate-N concentrations become low and more variable, and it is harder to identify the YML. The decline in critical N concentrations must be taken into account when interpreting the results of plant tests for diagnosing the N status of canola, as sampling needs to correspond to the plant growth stage for which a particular critical N concentration has been obtained.

scholarly journals Nitrogen Partitioning of Field-grown `Arapaho' Thornless Blackberry

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 487B-487
Author(s):  
J. Naraguma ◽  
J.R. Clark ◽  
R.J. Norman
Keyword(s):  
Dry Matter ◽  
Sampling Period ◽  
Nitrogen Partitioning ◽  
Plant Tissues ◽  
Old Field ◽  
Total N ◽  
Plant Parts ◽  
Whole Plant ◽  
Percent Recovery ◽  
Thornless Blackberry

A spring application of 19 g CO(15NH2)2/plant at 2.49% atom percent enrichment was made in Mar. 1995 on 2-year old, field-grown `Arapaho' blackberry plants. Individual plants were harvested during the study at preharvest (late May), postharvest (mid-July), and early dormancy (late October). The following plant parts were separated for analysis: roots, primocanes, floricanes, primocane leaves, floricane leaves, fruits. Soil samples were also taken from within the drip line of the plants at each sample date. Plant tissues were washed, dry weights measured and ground for acid digestion, total N determination and 15N analysis. Samples were measured for 15N atom percent abundance by a isotope ratio spectrometer. The whole-plant dry matter in creased during the season from 53 g in May to 153 g in October. Plants sampled in October had a greater amount of dry matter in roots than in any other tissue. There was a decreased total N content in all vegetative tissues (leaves and canes) from May to October. The maximum fertilizer 15N percent recovery was 43% (October) and the minimum was 12% (May) from the total plant tissues. Compared to other plant tissues, floricane leaves and primocanes recovered significantly more fertilizer 15N in May, while roots and primocane leaves recovered more in October. Floricanes and fruits did not increase in 15N levels during the sampling period. Fertilizer 15N recovered in the soil amounted to 35.5% of the applied with 4.5% found in the inorganic fraction, 31% in the organic fraction. There were no statistical differences in percent recovery of the fertilizer 15N among sample dates in the topsoil. October 15N percent recovery was much lower than May in the subsoil, indicating a downward movement of N by leaching. Averaging all sample dates, 59.5% of the labeled fertilizer was accounted for in the plant and soil, with the remaining portion probably lost via volatilization, leaching, and/or denitrification.

Determination of critical nitrogen concentrations of potato (Solanum tuberosum L. cv. Sebago) grown in sand culture

1992 ◽  
Vol 32 (6) ◽  
pp. 765 ◽  
Author(s):  
DO Huett ◽  
E White
Keyword(s):  
Dry Matter ◽  
Maximum Yield ◽  
Growth Period ◽  
Sand Culture ◽  
N Application ◽  
Total N ◽  
Nitrate N ◽  
Nitrate Concentrations ◽  
Petiole Sap ◽  
Leaf Nitrate

A gamma x cubic response surface model was used to predict the dry matter yield of potato cv. Sebago over the 12-week growth period in sand culture with nitrogen (N) levels of 2, 7, 14, 29 and 43 mmol N/L. At each 2-week sampling period after emergence, dry matter yield relative to maximum was plotted against tissue N concentration to derive diagnostic petiole, petiole sap, leaf nitrate-N and leaf total N in youngest fully opened leaf (YFOL), youngest fully expanded leaf (YFEL) and oldest green leaf (OL) and for total N in bulked leaves. Critical concentrations corresponding to 90% maximum yield are presented. Tissue nitrate was much more responsive than leaf total N to applied N over the 2-14 mmol/L range where positive growth responses to N were recorded. Plants grown with 2 mmol N/L were severely N deficient and growth was depressed. Tissue nitrate concentrations in these plants from 4 weeks after emergence onwards were negligible, while leaf total N concentrations exceeded 2.36%. Salt toxicity occurred at 29 and 43 mmol NIL, and it sometimes reduced tissue N concentrations so that adequacy and toxicity concentrations overlapped. Critical tissue N concentrations declined over the growth period, the largest decline occurring for nitrate. Critical tissue N concentrations for YFEL, from 2 weeks after emergence to final harvest were: petiole sap nitrate-N, 1.2-0.2 g/L; petiole nitrate-N, 2.1-0.1%; leaf nitrate-N, 0.44-0.08%. Critical tissue nitrate concentrations clearly differentiated between inadequate and adequate N application levels. Critical leaf total N concentrations only differentiated between inadequate and marginal N application rates, except for OL when inadequate and marginally adequate (80-90% maximum yield) concentrations were not different (P>0.05). Nitrogen application level affected (P<0.05) leaf potassium, phosphorus, calcium (Ca), magnesium (Mg) and sulfur concentrations. The largest effects were recorded for Ca and Mg where increasing N application level reduced leaf nutrient concentration. Petiole sap nitrate concentrations can be used as a rapid field test for distinguishing between a deficient and an adequate N supply. Where concentrations exceed critical values, they can be interpreted as such because N fertiliser toxicity rarely occurs under field conditions.

Determination of critical nitrogen concentrations of lettuce (Lactuca sativa L. cv. Montello) grown in sand culture

1992 ◽  
Vol 32 (6) ◽  
pp. 759 ◽  
Author(s):  
DO Huett ◽  
E White
Keyword(s):  
Dry Matter ◽  
Growth Period ◽  
Sand Culture ◽  
N Application ◽  
Total N ◽  
N Supply ◽  
Nitrate N ◽  
N Concentration ◽  
Nitrate Concentrations ◽  
Petiole Sap

A gamma x cubic response surface model was used to predict the dry matter yield of lettuce cv. Montello over the 8-week growth period in sand culture with nitrogen (N) levels of 2, 5, 11, 18 and 36 mmol/L. At 1, 2, 3, 5, 7 and 8 weeks after transplanting, dry matter yield relative to maximum was plotted against tissue N concentration to derive diagnostic concentrations of petiole sap nitrate-N and leaf total N in youngest fully opened leaf (YFOL), youngest fully expanded leaf (YFEL) and oldest green leaf (OL), and total N in bulked leaf samples. Critical concentrations corresponding to 90% maximum yield are presented. Growth was consistently depressed at 2 mmol N/L due to N deficiency, and at 36 mmol N/L due to salt toxicity. Petiole sap nitrate concentrations were more responsive than leaf total N concentrations to N application levels. Leaf N concentrations at N application levels of 18 and 36 mmol/L were often similar. Critical leaf total N concentrations in YFOL and YFEL decreased from 2 weeks after transplanting to maturity, whereas the opposite trend occurred for petiole sap nitrate concentrations. Critical total N concentration ranges in YFEL were 0.30-0.95 g/L for petiole sap nitrate-N, and 4.00-5.30% for leaf total N concentration. Critical leaf total N and petiole sap nitrate concentrations clearly differentiated between inadequate and adequate N application rates. Critical values in most cases, differentiated toxic concentrations. Nitrogen application levels of 2 and 36 mmol N/L reduced (P<0.05) potassium, calcium and magnesium concentrations in all leaves. This confirms the importance of optimising N supply when determining critical levels of these nutrients for lettuce. Petiole sap nitrate-N concentrations, which can be determined rapidly in the field, can be used to distinguish between a deficient and an adequate N supply. The marked increase in critical concentration over the growth period requires consecutive determinations to verify the N status of lettuce.

scholarly journals EFFECT OF MINERAL DEFICIENCY ON MORPHOLOGICAL AND PHYSIOLOGICAL PARAMETERS AND ON SHOOT AND ROOT MINERAL PARTITIONING IN THREE SUNFLOWER VARIETIES / EFECTO DE LA FALTA DE ELEMENTOS MINERALAS SOBRE LOS PARAMENTROS MORFOLOGICOS Y FISIOLOGICOS Y REPARTICION DE ELEMENTOS MINERALES DE LA PARTE SOBRE EL SUELO Y DE LA RAIZ EN TRES VARIEDADES / INFLUENCE DE LA CARENCE D’ÉLÉMENTS MINÉRAUX SUR LES PARAMÈTRES MORPHOLOGIQUES ET PHYSIOLOGIQUES ET SUR LA DISTRIBUTION DES ÉLÉMENTS MINÉRAUX ENTRE LA PARTIE AÉRIENNE ET LA RACINE POUR TROIS SORTES DE TOURNESOL

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 135-148
Author(s):  
Mohammed El Midaoui ◽  
Ahmed Talouizte ◽  
Benbella Mohamed ◽  
Serieys Hervé ◽  
Ait Houssa Abdelhadi ◽  
...  
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Growth Parameters ◽  
Dry Weight ◽  
Mineral Deficiency ◽  
P Deficiency ◽  
Plant Parts ◽  
Shoot Dry Weight ◽  
K Deficiency ◽  
Matter Effect

SUMMARYAn experiment has been carried out in order to study the behaviour under mineral deficiency of three sunflower genotypes, a population variety (Oro 9) and two hybrids (Mirasol and Albena). Sunflower seedlings were submitted to five treatments: N deficiency (N0), P deficiency (P0), K deficiency (K0), N and K deficiency (N0K0) and a control. Plants were harvested when they reached 3-4 true pairs of leaves. Growth parameters measured (height, total leaf area, root length, root and shoot dry mater) were all significantly reduced by mineral deficiency. Leaf area was most reduced by N0 (-61%) and P0 (-56%). Total dry matter was most affected by N0 (-63%) and by N0K0 (-66%). Genotype comparisons showed that Oro 9 had the highest shoot dry matter while Albena had the lowest root dry matter. Effect of mineral deficiency on content and partitioning of N, P, K, Ca and Na was significant and varied according to treatments and among plant parts. Shoot dry weight was significantly correlated with root N content (r2=0.81) and root K content (r2=-0.61) for N0 and K0.

scholarly journals Gentiana asclepiadea L. from Two High Mountainous Habitats: Inter- and Intrapopulation Variability Based on Species’ Phytochemistry

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 140
Author(s):  
Zorica Popović ◽  
Dijana Krstić-Milošević ◽  
Milena Marković ◽  
Vera Vidaković ◽  
Srđan Bojović
Keyword(s):  
Secondary Metabolites ◽  
Natural Populations ◽  
Chemical Compounds ◽  
Clear Separation ◽  
Plant Parts ◽  
Intrapopulation Variability ◽  
Population Origin

Natural populations of Gentiana asclepiadea L., located at two mountainous sites, were HPLC-analyzed regarding the contents of six representative secondary metabolites. The contents of swertiamarin (SWM), gentiopicrin (GP), sweroside (SWZ), mangiferin (MGF), isoorientin (ISOOR), and isovitexin (ISOV) were determined in six populations (three per study site), and separately for aboveground and belowground plant parts. PCA showed a clear separation of four groups according to the contents of the analyzed secondary metabolites. Out of six analyzed compounds, five were present in all samples and only one (SWZ) was found in Golija populations (belowground parts) but not in Vlasina populations, and its presence can be indicative of the geolocation of populations. Clear separation of groups was mostly affected by the different contents of chemical compounds in plant parts (aboveground versus belowground) and by the differences related to population origin (higher content of SWM and GP in belowground parts of individuals from Vlasina populations and higher content of MGF and ISOOR of individuals from Golija populations). The results of this study contribute to the spatiochemical profiling of G. asclepiadea populations and a better understanding of inter- and intrapopulation variability of pharmacologically important compounds.

scholarly journals Some factors influencing the chemical composition of mixed rumen bacteria

1974 ◽  
Vol 31 (1) ◽  
pp. 27-34 ◽  
Author(s):  
R. H. Smith ◽  
A. B. Mcallan
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Rumen Bacteria ◽  
Host Animal ◽  
Adult Cattle ◽  
Total N ◽  
Adult Sheep ◽  
Factors Influencing ◽  
Mixed Bacteria ◽  
Ciliate Protozoa

1. Sheep, cows and calves fitted with rumen cannulas were given diets mostly containing 10–16 g nitrogen/kg dry matter and consisting of roughage and cereals. Mixed bacteria were separated from samples of their rumen contents.2. Bacteria taken 4–6 h after a feed from calves which were kept in an experimental calf-house with no contact with adult animals (environment A) contained more α-dextran, less total N and higher nucleic acid:total N ratios than similar bacteria from calves reared in contact with adult sheep (environment C) but otherwise treated in an identical way.3. Mixed bacteria taken 4–6 h after a feed from sheep and cows were similar in composition, with respect to nitrogenous components, to those from the ‘environment C’ calves. This composition did not vary significantly when diets containing differing proportions of roughage were given.4. The ‘environment A’ calves were free of ciliate protozoa. When they were placed in contact with, and were inoculated with rumen contents from, adult cattle (environment B), they rapidly developed a normal protozoal population and the chemical composition of their rumen bacteria became like that of the bacteria from the ‘environment C’ calves.5. Mixed bacteria taken just before a feed, from either cows or ‘environment A’ calves, showed significantly lower RNA-N:total N ratios and slightly (but not usually significantly) higher DNA-N:total N ratios than bacteria taken 4–6 h after feeding. Total N contents of the bacteria did not change consistently with time after feeding.6. The possible significance of these differences in relation to the nutrition of the host animal is discussed.

Distribution of Biomass, Nitrogen, Phosphorus and Other Nutrients in Banksia marginata and B. ornata Shoots of Different Ages After Fire.

1986 ◽  
Vol 34 (6) ◽  
pp. 709 ◽  
Author(s):  
RH Groves ◽  
PJ Hocking ◽  
A Mcmahon
Keyword(s):  
National Park ◽  
Dry Matter ◽  
Lateral Roots ◽  
South Australia ◽  
Distribution Patterns ◽  
Nutrient Accumulation ◽  
Nitrogen And Phosphorus ◽  
Vegetative Organs ◽  
Western Victoria ◽  
Nitrogen Phosphorus

The heathland form of Banksia marginata Cav. regenerates rarely from seed but commonly by resprout- ing from buds on lateral roots, whereas Banksia ornata F. Muell. regenerates only from seed, usually released after fire. The two species co-occur in heath vegetation on nutrient-poor soils in south-eastern South Australia and western Victoria. Shoots were sampled from stands of B. marginata aged from 1 to 25 years and of B. ornata aged from 1 to 50+ years after fire in the Little Desert National Park, western Victoria. B. marginata, the resprouter, distributed a greater proportion of the total shoot dry matter and content of all nutrients to vegetative growth over its shorter life span than B. ornata, the non-sprouter. About 50% of the total phosphorus in B. ornata shoots at 50+ years was present in cones (including seeds) compared with only about 20% in B. marginata shoots at a comparable stage of senescence (25 years). This difference between the species was also true to a lesser degree for nitrogen. There were considerable differences between other nutrients in their distribution patterns in shoots. Nutrients could be grouped together on the basis of distribution in shoots more satisfactorily than on presumed physio- logical roles. Stems were major sites of nutrient accumulation in both species. The content of a particular nutrient in seeds as a proportion of the content in the living parts of the shoot ranged from 0.03% (Na, Mn) to 2.0% (P) in B. marginata, and from 0.3% (Na) to as high as 31% (P) in B. ornata. Concen- trations of all nutrients except sodium were much higher in seeds than in the woody cones or vegetative organs of both species; seeds of B. ornata were particularly rich in calcium and manganese. We conclude that the different patterns of distribution of biomass and nutrients, especially nitrogen and phosphorus, within shoots of the two species reflect their different regenerative modes after fire. Introduction Phosphorus and, to a lesser extent, nitrogen limit the growth of sclerophyllous shrubs on nutrient-poor soils in southern Australia

scholarly journals Symbiotic capability of calopo rhizobia from an agrisoil with different crops in Pernambuco

2013 ◽  
Vol 37 (4) ◽  
pp. 869-876 ◽  
Author(s):  
Altanys Silva Calheiros ◽  
Mario de Andrade Lira Junior ◽  
Débora Magalhães Soares ◽  
Márcia do Vale Barreto Figueiredo
Keyword(s):  
Dry Matter ◽  
Nitrogen Sources ◽  
Dry Weight ◽  
Dry Forest ◽  
Forest Zone ◽  
Symbiotic Efficiency ◽  
Total N ◽  
Calopogonium Mucunoides ◽  
Legume Symbiosis ◽  
Biological Nitrogen

Biological nitrogen fixation by rhizobium-legume symbiosis represents one of the most important nitrogen sources for plants and depends strongly on the symbiotic efficiency of the rhizobium strain. This study evaluated the symbiotic capacity of rhizobial isolates from calopo (CALOPOGONIUM MUCUNOIDES) taken from an agrisoil under BRACHIARIA DECUMBENS pasture, sabiá (MIMOSA CAESALPINIIFOLIA) plantations and Atlantic Forest areas of the Dry Forest Zone of Pernambuco. A total of 1,575 isolates were obtained from 398 groups. A single random isolate of each group was authenticated, in randomized blocks with two replications. Each plant was inoculated with 1 mL of a bacterial broth, containing an estimated population of 10(8) rhizobial cells mL-1. Forty-five days after inoculation, the plants were harvested, separated into shoots, roots and nodules, oven-dried to constant mass, and weighed. Next, the symbiotic capability was tested with 1.5 kg of an autoclaved sand:vermiculite (1:1) mixture in polyethylene bags. The treatments consisted of 122 authenticated isolates, selected based on the shoot dry matter, five uninoculated controls (treated with 0, 50, 100, 150, or 200 kg ha-1 N) and a control inoculated with SEMIA 6152 (=BR1602), a strain of BRADYRHIZOBIUM JAPONICUM The test was performed as described above. The shoot dry matter of the plants inoculated with the most effective isolates did not differ from that of plants treated with 150 kg ha-1 N. Shoot dry matter was positively correlated with all other variables. The proportion of effective isolates was highest among isolates from SABIÁ forests. There was great variation in nodule dry weight, as well as in N contents and total N.

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