The narrow-leafed lupin (Lupinus angustifolius L.) as a nitrogen-fixing rotation crop for cereal production. I. Indices of nitrogen fixation

1988 ◽  
Vol 39 (6) ◽  
pp. 1003 ◽  
Author(s):  
DF Herridge
Keyword(s):  
N2 Fixation ◽  
Plant Size ◽  
Lupinus Angustifolius ◽  
Xylem Exudate ◽  
Plant Parts ◽  
Rooting Medium ◽  
Rhizobium Lupini ◽  
Nitrate Supply ◽  
Root Tissues ◽  
Rotation Crop

Experiments to develop indices of N2 fixation activity for the narrow-leafed lupin (Lupinus angustifolius L.) are reported. In Experiment 1 Unicrop narrow-leafed lupins were inoculated at sowing with effective Rhizobium lupini WU425. The conversion factor relating C2H2 reduction to N2 fixation was not constant throughout growth but increased from 0.9 (50-60 day period) to 6.6 (110-120 days). A nodulation index [(nodule wt/shoot wt) x 100], developed to account for plant size, declined with increasing nitrate supply and with increasing plant age. However, minor shifts in the nodulation index represented large shifts in plant dependence on N2 fixation (p), when plants were 60-100% dependent on N2 fixation. Concentrations of nitrate in extracts of the shoot axes and nodulated roots increased with increasing nitrate supply. Although the presence of nitrate in the rooting medium was evidenced by its presence in xylem exudate, the relationship between nitrate supply and the nitrate contents of xylem exudate was generally poor. Functions were developed to describe the relationships between the nodulation index and p, and between both shoot and root nitrate and p. Other experiments highlighted the synchrony of nitrate supply and its appearance in root tissues and the lack of diurnal fluctuations in nitrate concentrations of plant parts.

The impact of elevated atmospheric CO2 and nitrate supply on growth, biomass allocation, nitrogen partitioning and N2 fixation of Acacia melanoxylon

1999 ◽  
Vol 26 (8) ◽  
pp. 737 ◽  
Author(s):  
Marcus Schortemeyer ◽  
Owen K. Atkin ◽  
Nola McFarlane ◽  
John R. Evans
Keyword(s):  
Elevated Co2 ◽  
N2 Fixation ◽  
Dry Matter ◽  
Co2 Concentration ◽  
Dry Mass ◽  
Nitrogen Partitioning ◽  
Atmospheric Co2 ◽  
Acacia Melanoxylon ◽  
Nitrate Supply ◽  
The Impact

The interactive effects of nitrate supply and atmospheric CO2 concentration on growth, N2 fixation, dry matter and nitrogen partitioning in the leguminous tree Acacia melanoxylon R.Br. were studied. Seedlings were grown hydroponically in controlled-environment cabinets for 5 weeks at seven 15N-labelled nitrate levels, ranging from 3 to 6400 mmol m–3. Plants were exposed to ambient (~350 µmol mol–1) or elevated (~700 µmol mol–1) atmospheric CO2 for 6 weeks. Total plant dry mass increased strongly with nitrate supply. The proportion of nitrogen derived from air decreased with increasing nitrate supply. Plants grown under either ambient or elevated CO2 fixed the same amount of nitrogen per unit nodule dry mass (16.6 mmol N per g nodule dry mass) regardless of the nitrogen treatment. CO2 concentration had no effect on the relative contribution of N2 fixation to the nitrogen yield of plants. Plants grown with ≥50 mmol m–3 N and elevated CO2 had approximately twice the dry mass of those grown with ambient CO2 after 42 days. The rates of net CO2 assimilation under growth conditions were higher per unit leaf area for plants grown under elevated CO2. Elevated CO2 also decreased specific foliage area, due to an increase in foliage thickness and density. Dry matter partitioning between plant organs was affected by ontogeny and nitrogen status of the plants, but not by CO2 concentration. In contrast, plants grown under elevated CO2 partitioned more of their nitrogen to roots. This could be attributed to reduced nitrogen concentrations in foliage grown under elevated CO2.

Estimating Nitrogenase Activity of Faba Bean (Vicia faba) by Acetylene Reduction (Ar) Assay

1990 ◽  
Vol 17 (5) ◽  
pp. 489 ◽  
Author(s):  
Herdina ◽  
JH Silsbury
Keyword(s):  
Diurnal Variation ◽  
Vicia Faba ◽  
Faba Bean ◽  
Closed System ◽  
N2 Fixation ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Electron Flow ◽  
Specific Rate ◽  
Rooting Medium

Methods of conducting acetylene reduction (AR) assay were appraised for estimating the nitrogenase activity of nodules of faba bean (Vicia faba L.). Factors considered were: (i) disturbance of plants when removing the rooting medium; (ii) assay temperature; (iii) the use of whole plants rather than detached, nodulated roots; (iv) diurnal variation in nodule activity; and (v) a decline in C2H4 production after exposure to C2H2. Plants growing in jars of 'oil dry' (calcined clay) had the same AR activity when assayed in situ in a closed system as when assayed after removal of the rooting medium. Assay temperatures of 12.5, 17.5 and 22.5°C influenced the specific rate of AR with the optimum at 17.5°C. Removal of the shoot resulted in a rapid decrease in AR activity in both vegetative and reproductive plants but the effect was much larger in the latter. AR and respiration by nodulated roots were closely linked and both varied markedly over a diurnal 12 h/12 h cycle. Since no fluctuation was found after nodules were detached, diurnal variation in the respiration of nodulated roots is attributed to change in nodule activity. Half of the dark respiration of nodulated roots was associated with respiration of the nodules and thus largely with N2 fixation. Since the AR assay provides no information on how electron flow in vivo is partitioned between reduction of N2 and reduction of protons, diurnal variation in hydrogen evolution (HE) in air and Ar/O2 in an open system was used to estimate this partitioning. Diurnal variation in apparent N2 fixation estimated in this manner was examined at a 'low' PPFD (300 μmol m-2 s-1) and at 'high' (1300 μmol m-2 s-1) to explore whether variation could be attributed to change in carbohydrate supply. Although HE in air and in Ar/O2 were both closely linked with the respiration of the nodulated root, apparent N2 fixation showed only a slight diurnal variation at 'low' light and almost none at 'high'. Vegetative plants showed no C2H2-induced decline in activity with exposure to C2H2 but reproductive plants did. This difference appears to be an age effect rather than attributable to flowering per se, since a decline occurred even when plants were kept vegetative by disbudding. A closed system for AR assay appears satisfactory for vegetative faba bean but such an assay over a 40-min period during the reproductive stage would underestimate nitrogenase activity by about 20%.

Mobilization of stored nitrate in broccoli (Brassica oleracea var. italica)

1995 ◽  
Vol 75 (3) ◽  
pp. 709-715 ◽  
Author(s):  
Liangxue Liu ◽  
Barry J. Shelp
Keyword(s):  
Brassica Oleracea ◽  
Nitrate Removal ◽  
Xylem Sap ◽  
Plant Size ◽  
Nitrate Content ◽  
Dry Matter Accumulation ◽  
Inflorescence Development ◽  
Sodium Potassium ◽  
Nitrate Supply ◽  
Sulphate Salts

The study tested the hypothesis that substitution of nitrate supply with other anions induces the mobilization of stored nitrate in broccoli (Brassica oleracea var. italica) plants. Broccoli plants, grown under greenhouse conditions in soilless culture, were provided with either a continuous supply of nitrate in the nutrient solution until commercial maturity, or with a nitrate supply only up to inflorescence emergence. At inflorescence emergence, nitrate was also substituted with various chloride or sulphate salts of sodium, potassium and ammonium (15 and 5 mmol L−1). During the period of inflorescence development studied, plant size increased by two- to threefold. Nitrate removal or its substitution with chloride or sulphate salts of sodium and potassium (15 mmol L−1) resulted in 13% less dry-matter accumulation and 63–97% less xylem-sap nitrate than continuous nitrate supply, and 57–62% decline in the plant-nitrate content found at inflorescence emergence. In contrast, chloride or sulphate salts of ammonium (5 mmol L−1) sustained plant growth, while also decreasing xylem-sap nitrate by 83–90% and plant-nitrate content by 58–62%. Phloem-exudate nitrate of plants receiving nitrate continuously was only 7% of that of xylem sap, and was decreased by 63% by an interrupted nitrate supply. Therefore, the removal of nitrate and substitution with a low supply of ammonium, rather than other anions, is recommended for decreasing plant-nitrate content. Key words: Broccoli, chloride, mobilization, nitrate, sulphate

Fruit Set in Lupinus angustifolius Cv. Unicrop. II. Assimilate Flow During Flowering and Early Fruiting

1981 ◽  
Vol 8 (3) ◽  
pp. 307 ◽  
Author(s):  
JS Pate ◽  
P Farrington
Keyword(s):  
Lupinus Angustifolius ◽  
Main Stem ◽  
Carbon Dioxide Exchange ◽  
Sink Strength ◽  
Plant Parts ◽  
Single Leaf ◽  
Lateral Shoots ◽  
Using Data ◽  
A Minor ◽  
Stem Leaf

Assimilate distribution in Lupinus angustifolius was studied during 7 weeks after emergence of the main inflorescence by feeding [14C]urea to a single leaf or group of leaves on a plant and measuring 14C in plant parts 24 h after feeding. Nine times of feeding were involved, each with 14C treatments encompassing leaves of the main stem and first-order laterals. The inflorescence was a minor sink for assimilates compared with root, main stem and developing lateral shoots. During the first 4 weeks the inflorescence relied on main stem leaves, especially the upper leaves, but in the fifth week leaves of upper laterals became principal sources of assimilates. The transition occurred after four to six basal fruits had set, and just as upper flowers were commencing to abscise. Estimates were made of transfer of photosynthetically fixed carbon from the uppermost main stem leaf to the inflorescence, using data on carbon dioxide exchange and changes in carbon content of this leaf and its translocatory commitment to the inflorescence as determined by 14C feeding. Assimilate flow from leaves to flowers was confined largely to organs of the same or adjacent orthostichies (2/5 phyllotaxis), but these affinities became less definite during fruiting. Import of 14C by reproductive units was related to phenology, position on an inflorescence, and accumulation of dry matter. All flowers attracted assimilates strongly at the bud stage but lost sink strength progressively after opening. Upper flowers destined to abscise failed to import assimilates or to bleed from phloem for several days before being shed. Lower flowers which set fruits showed a rapid resurgence of sink strength once their corollas had senesced and the young fruits had commenced to elongate.

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.

Variation in Natural Abundance of 15N among Plant Parts and in 15N/14N Fractionation during N2 Fixation in the Legume-Rhizobia Symbiotic System

1986 ◽  
Vol 27 (5) ◽  
pp. 791-799 ◽  
Author(s):  
Tadakatsu Yoneyama ◽  
Kounosuke Fujita ◽  
Tomio Yoshida ◽  
Tetsuo Matsumoto ◽  
Iwao Kambayashi ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Natural Abundance ◽  
Symbiotic System ◽  
Plant Parts

Responces of Typha domingensis to salinity and high levels of maganese in the rooting medium

1981 ◽  
Vol 32 (6) ◽  
pp. 907 ◽  
Author(s):  
PJ Hocking
Keyword(s):  
Sodium Chloride ◽  
Manganese Sulfate ◽  
Plant Parts ◽  
Nitrogen Levels ◽  
Sulfate Solutions ◽  
Rooting Medium ◽  
Calcium Magnesium ◽  
High Concentrations ◽  
Chloride Treatment ◽  
Saline Solutions

The response of T. domingensis, a large emergent macrophyte, to salinity and manganese was studied under glasshouse conditions. Plants were grown in saline solutions ranging in concentration from 0.5 to 100 mM NaCI. and in manganese sulfate solutions ranging in concentration from 0.01 to 10 mM. Growth was reduced slightly at 50 mM NaCl and severely at 100 mM NaC1, suggesting that T. domingensis is moderately salt tolerant. Plant parts had highest chloride levels at 25 mM NaCl and highest sodium levels at 100 mM NaCl. The highest sodium chloride treatment reduced the level of potassium in the rhizomes, but not in roots or leaves. Sodium chloride had no effect on the concentration of nitrate in organs, but total nitrogen levels in roots and rhizomes increased at 100 mM NaCI. Sodium was considered to be more toxic than chloride. Growth in manganese solutions was unaffected except at the highest concentration used. Manganese accumulated quickly in leaves to levels which would be toxic to livestock; leaves retaining over 70% of the total manganese in the plant. Manganese applied at high concentrations substantially reduced the levels of calcium, magnesium and phosphorus in the leaves. In a field experiment, there were seasonal changes in the levels of selected elements in the leaves of T. domingensis. During leaf senescence. concentrations of sodium, manganese and calcium increased by 20-80%, but levels of phosphorus, nitrogen, potassium and maganesium fell by 65-84%. The results are discussed in relation to the use of T. domingensis in Hastewater reclamation.

The narrow-leafed lupin (Lupinus angustifolius L.) as a nitrogen-fixing rotation crop for cereal production. II. Estimates of fixation by field-grown crops

1988 ◽  
Vol 39 (6) ◽  
pp. 1017 ◽  
Author(s):  
DF Herridge ◽  
AD Doyle
Keyword(s):  
Dry Matter ◽  
New South ◽  
Maximum Activity ◽  
Lupinus Angustifolius ◽  
C2h2 Reduction ◽  
South Wales ◽  
Rapid Accumulation ◽  
Seed Yields ◽  
Rotation Crop ◽  
The Impact

Experiments were commenced in 1978 to evaluate the impact of the narrow-leafed lupin (Lupinus angustifolius L.) on production of subsequent wheat crops in the N-infertile, acidic soils of the Pilliga Scrub region of northern New South Wales. There were four sites. Production of lupin dry matter (shoots, roots) ranged from 5.0 (Florida A) to 11.4 t ha-1 (Kamala), reflecting seasonal rainfall and crop management. Lupin seed yields varied between 1.29 (Florida A) and 2.03 t ha-1 (Kamala); at two of the sites, yields were greater than the yields achieved by the adjacent wheat crops. At Spring Creek, the wheat was not harvested for grain due to the extremely poor plant growth. Seasonal profiles of C2H2 reduction by each of the four lupin crops reflected growth characteristics; maximum activity coincided with rapid accumulation of dry mater. Diurnal profiles of C2H2 reduction were unaffected by plant age. Rates peaked around noon after rapidly increasing from minimum pre-dawn levels. Total N2 fixed by each of the lupin crops was estimated by comparing N Yields of the lupin and wheat crops. The various methods used resulted in almost identical estimates of N2 fixation at Kamala (215-218 kg ha-') and Spring Creek (222-228 kg ha-'). Estimates . of N2 fixed by the two Florida crops ranged from 72 to 101 (Florida A) and from 82 to 134 kg ha-' (Florida B). The data indicate that large amounts of N can be fixed by field-grown lupins, amounts well in excess of the quantities of N harvested in the seed.

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