Temporal changes in carbon dioxide exchange rates, acetylene reduction and distribution of nitrogen in Barrel Medic (Medicago trunculata Gaertn.) grown in the field

1986 ◽  
Vol 37 (3) ◽  
pp. 263 ◽  
Author(s):  
AM Alston ◽  
DW Puckridge
Keyword(s):  
Carbon Dioxide ◽  
Exchange Rates ◽  
Nitrogen Content ◽  
Environmental Conditions ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Carbon Dioxide Exchange ◽  
Plant Nitrogen ◽  
Barrel Medic

Barrel medic (cv. Jemalong) was grown on a red-brown earth at Adelaide to examine dry matter production and nitrogenase activity in relation to environmental conditions and carbon dioxide exchange. At 4-10-day intervals, measurements were made of dry weight and nitrogen content in plant parts, and mineral nitrogen content of the soil. Rates of acetylene reduction and carbon dioxide exchange, and environmental variables were measured. Curves fitted to data for solar radiation and carbon exchange rate were used to calculate daily values for net carbon dioxide uptake. Estimates of dry weight production derived from these net uptakes of carbon dioxide gave a similar curve to measured dry weight, but overestimated maximum dry weight by almost 20%. The difference is presumed to be due to materials lost from the roots. At maturity, dry weight and plant nitrogen content had declined by 10 and 14% respectively from their maxima of 1.02 kg m-2 and 26.1 g m-2 in October. All fractions of the plant except the litter and seed lost nitrogen. Rates of acetylene reduction reached a maximum of 39 mmol m-2 day-1 104 days from sowing, when the medic began to flower, and declined to almost zero by 145 days. At this time carbon dioxide exchange rates were high, and the plants were still accumulating nitrogen; from approximately 14 g N m-2 at day 104 to 24 g N m-2 at day 145. These changes are discussed in relation to environmental conditions and soil nitrogen content.

Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop

1975 ◽  
Vol 26 (3) ◽  
pp. 497 ◽  
Author(s):  
EAN Greenwood ◽  
P Farrington ◽  
JD Beresford
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Leaf Area ◽  
Time Course ◽  
Dry Weight ◽  
Grain Filling ◽  
Main Axis ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Plant Parts

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.

Effect of weed management on weeds, and on the nodulation, nitrogenase activity, growth and yield of pea (Pisum sativum)

2006 ◽  
Vol 54 (4) ◽  
pp. 469-485 ◽  
Author(s):  
G. Singh ◽  
D. Wright
Keyword(s):  
Pisum Sativum ◽  
Nitrogen Content ◽  
Weed Management ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Strong Relationship ◽  
Dry Weight ◽  
Growth And Yield ◽  
N Content ◽  
Shoot Dry Weight

Effects of one pre-emergence herbicide (terbutryn/terbuthylazine) and one post-emergence herbicide (bentazone) along with unweeded and hand-weeded controls on weeds and on the nodulation, nitrogenase activity, nitrogen content, growth and yield of pea (Pisum sativum) were studied. Terbutryn/terbuthylazine was applied pre-emergence @ 1.40, 2.80 and 5.60 kg/hawhereas bentazone was sprayed 6 weeks after sowing @ 1.44, 2.88 and 5.76 kg/h. Terbutryn/terbuthylazine controlled all the weeds very effectively, whereas bentazone did not control some weeds such as Polygonum aviculare, Poa annua and Elymus repens. The herbicides decreased the number of nodules, the dry weight of nodules, the nitrogenase activity, the shoot dry weight, the nitrogen content in the straw and seeds, and the seed yield of peas, the effects generally being higher at higher rates of application. The adverse effects of herbicides on these parameters might be due to their effects on plant growth, as both the herbicides are known to adversely affect photosynthesis. Nitrogenase activity did not correlate well with plant-N content or shoot dry weight. However, there was a strong relationship between plant biomass and plant-N content, which suggests that researchers can rely on these parameters for studying the effects of treatments on nitrogen fixation, rather than measuring nitrogenase activity.

Rehydration response of nitrogenase activity and carbon fixation in terrestrial Nostoc commune from Stipa–Bouteloa grassland

1983 ◽  
Vol 61 (10) ◽  
pp. 2658-2668 ◽  
Author(s):  
D. S. Coxson ◽  
K. A. Kershaw
Keyword(s):  
Respiratory Burst ◽  
Acetylene Reduction ◽  
Carbon Fixation ◽  
Light Exposure ◽  
Nitrogenase Activity ◽  
Net Photosynthesis ◽  
Rapid Decline ◽  
Carbon Dioxide Exchange ◽  
Nostoc Commune ◽  
Lower Temperature

The effects of wetting–drying cycles on patterns of carbon dioxide exchange and acetylene reduction were examined for colonies of the terrestrial cyanophyte Nostoc commune collected from a semiarid grassland site in southern Alberta, Canada. At 14 and 21 °C acetylene reduction takes ca. 14 h to resume maximal rates, although activity is detected within minutes of rehydration. Net photosynthesis reaches compensation minutes after rehydration and is maximal in under 80 min at 21 °C. No respiratory burst is evident, either for replicates previously dried rapidly (0.5 h) or slowly (5 h). In marked contrast, however, at 7 °C only minimal recovery of acetylene reduction is evident after 48 h diurnal treatment, while net photosynthesis requires a recovery time of 6 h. Again no respiratory burst is evident. After rehydration, the magnitude of acetylene reduction is strongly dependent on both the previous illumination level and temperature. The rapid decline in activity on transfer to darkness or on addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea can be moderated by increasing the duration of the previous light exposure or by incubation at lower temperature. This suggests the presence of substrate pools, the replenishment of which by photosynthesis allows oxidative phosphorylative support of nitrogenase activity in the dark. The extreme resistance of N. commune to desiccation and heat stress combined with its ability to resume metabolic activity within minutes of wetting should allow very effective utilization of small precipitation events during the summer months. The slower recovery of nitrogenase activity upon rehydration at lower temperatures may restrict winter field activity on rare occasions when thalli become dehydrated between snowfall periods.

Rhizobial inoculant formulations and soil pH influence field pea nodulation and nitrogen fixation

2000 ◽  
Vol 80 (3) ◽  
pp. 395-400 ◽  
Author(s):  
W. A. Rice ◽  
G. W. Clayton ◽  
P. E. Olsen ◽  
N. Z. Lupwayi
Keyword(s):  
Nitrogen Content ◽  
Soil Ph ◽  
Crop Production ◽  
Plant Biomass ◽  
Acid Soil ◽  
Dry Weight ◽  
Field Pea ◽  
Total Biomass ◽  
Plant Nitrogen ◽  
Liquid Inoculant

Crop production systems that include field pea (Pisum sativum L.) in rotation are important for sustainable agriculture on acid soils in northwestern Canada. Greenhouse experiments were conducted to compare the ability of liquid inoculant applied to the seed, powdered peat inoculant applied to the seed, and granular inoculant applied in a band with the seed to establish effective nodulation on field pea grown at soil pH(H2O) 4.4, 5.4 and 6.6. Plants were grown to the flat pod stage, and then total plant biomass dry weight, dry weight of nodules, number of nodules, plant nitrogen content, and proportion of plant nitrogen derived from the atmosphere (%Ndfa) were measured. Granular and powdered peat inoculants produced greater nodule numbers and weight, plant nitrogen content, %Ndfa and total biomass than liquid inoculant in at least two of the three experiments. Only granular inoculant was effective in establishing nodules at soil pH 4.4, but granular and powdered peat inoculants were effective at pH 5.4, and all three formulations were effective at pH 6.6. The results showed that granular inoculant has potential for effective nodulation of field pea grown on acid soil. Key words: Rhizobium, inoculant formulations, field pea, nodulation, acid soil

Fixation, accumulation, and distribution of nitrogen in a crop of Lupinus angustifolius cv. Unicrop

1977 ◽  
Vol 28 (2) ◽  
pp. 237
Author(s):  
P Farrington ◽  
EAN Greenwood ◽  
ZV Titmanis ◽  
MJ Trinick ◽  
DW Smith
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Content ◽  
Acetylene Reduction ◽  
Grain Filling ◽  
Plant Nitrogen ◽  
Balance Sheets ◽  
Reduction Assay ◽  
Beginning Of Flowering ◽  
Proportional Distribution

A lupin crop was sampled each week to measure nitrogen fixation by acetylene reduction assay and for determination of the total nitrogen content on the organs on each axis of the plant. Nitrogen fixation started 5 weeks after sowing, reached its maximum rate per plant at the beginning of flowering on the main axis, and ceased during the period of rapid grain filling, which was 4 weeks before maturity. Plants did not accumulate measurable quantities of nitrogen until 2 weeks after the start of nodular fixation as indicated by acetylene reduction. In the vegetative phase within each order of axes most nitrogen went to the leaves before they senesced. During the first half of the period of rapid grain filling, both the weight and the concentration of nitrogen in the grain increased at the expense of the vegetative components. Balance sheets for nitrogen content and the current proportional distribution of nitrogen are presented for three occasions at weeks 8-9, weeks 15-16 and weeks 18–19. Waterlogging greatly decreased acetylene reduction and plant growth.

CARBON DIOXIDE EXCHANGE RATES OF FRUITING SOYBEAN PLANTS EXPOSED TO OZONE AND SULPHUR DIOXIDE SINGLY OR IN COMBINATION

1984 ◽  
Vol 64 (1) ◽  
pp. 69-75 ◽  
Author(s):  
N. M. LE SUEUR-BRYMER ◽  
D. P. ORMROD
Keyword(s):  
Carbon Dioxide ◽  
Glycine Max ◽  
Exchange Rates ◽  
Sulphur Dioxide ◽  
Net Photosynthesis ◽  
Exposure Period ◽  
Carbon Dioxide Exchange ◽  
Continuous Stirred Tank Reactor ◽  
Glycine Max L ◽  
Soybean Plants

Carbon dioxide exchange rates (CER) of intact soybean (Glycine max (L.) Merr.) plants at the fruiting stage were measured in continuous stirred tank reactor (CSTR) chambers. Plants were exposed to clean air, 67 ppb ozone (O3), 300 ppb sulphur dioxide (SO2), or 67 ppb O3 plus 300 ppb SO2 for 7.5 h∙day−1 for 5 days. Carbon dioxide exchange rates were measured hourly during the last 6 h of each exposure period and decreased progressively during the first period of exposure to O3 plus SO2, dropping in hour 6 to 42% of the hour 1 rate, and to a lesser extent in the second daily exposure when the corresponding decline was to 70%. There was a declining trend in CER of SO2-treated but not O3-treated plants with increasing number of days of exposure. Carbon dioxide exchange rates of all plants generally peaked and declined during each exposure period.Key words: Air pollution, net photosynthesis, mixtures, Glycine max

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