scholarly journals Physical Environment and Symbiotic Nitrogen Fixation VI. Nitrogen Retention Within the Nodules of Trifolium Subterraneum L

1969 ◽  
Vol 22 (4) ◽  
pp. 829 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Effective Strain ◽  
Nitrogen Retention ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Root Temperature ◽  
Protein Nitrogen ◽  
The Difference ◽  
Nodule Tissue

The effect of bacterial strain and root temperature on the retention of nitrogen in the root system of Trifolium Bubterraneum plants was re-examined. The root systems of plants nodulated by the moderately effective Rhizobium trifolii strain NA30 possessed a higher percentage nitrogen than those nodulated by the fully effective strain TAl, although the number of nodules formed by each strain was similar. The difference was due to a greater weight of nodule tissue on the NA30-nodulated plants, and also to a higher percentage nitrogen in the NA30 nodules; this latter effect was due to a higher concentration of non-protein nitrogen. The overall effect of these differences was to reduce the amount of nitrogen translocated to the shoots of the NA30 plants, in both absolute terms and as a proportion of the total amount of nitrogen fixed. Another difference between the two strains was the rate of nitrogen fixation per unit (dry weight or leghaemoglobin content) of nodule tissue.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation II. Root Temperature Effects on the Relative Nitrogen Assimilation Rate

1965 ◽  
Vol 18 (2) ◽  
pp. 295 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Temperature Effects ◽  
Nitrogen Assimilation ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Bacterial Strains ◽  
Root Temperature ◽  
Relative Growth ◽  
Relative Growth Rates

Nitrogen fixation by six varieties of Trifolium subterraneum L., each inoculated with a number of strains of Rhizobium trifolii, was examined over a range of root temperatures. Significant differences in the rate of nodule establishment and early nitrogen fixation were found between varieties, and between bacterial strains. In order to minimize the effect of such differences, relative nitrogen assimilation rates (RN) and relative growth rates (R w) were used to compare the different legume-bacteria associations.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation III. Root Temperature Effects on Shoot and Root Development and Nitrogen Distribution In Trifolium Subterraneum

1966 ◽  
Vol 19 (2) ◽  
pp. 219 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Temperature Effects ◽  
Shoot Growth ◽  
Symbiotic Nitrogen Fixation ◽  
Root Nodules ◽  
Trifolium Subterraneum ◽  
Root Temperature ◽  
Nitrogen Distribution ◽  
Root And Shoot Growth

Root and shoot growth, and the distribution of nitrogen to the roots and shoots, were examined in five varieties of Trifolium subterraneum. The plants were grown between 5 and 30�0 root temperature, and received their nitrogen from root nodules, or as ammonium nitrate.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation. IV. Faotors Affecting the Early Stages of Nodulation

1967 ◽  
Vol 20 (6) ◽  
pp. 1087 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Light Period ◽  
Root Temperature ◽  
Early Stages ◽  
Temperature Conditions ◽  
General Decline ◽  
Effect Of Light

The influence of root temperature on the initial nodulation of Trifolium subterraneum L. was examined, and observations were made on the effect of light period and shoot temperature on this character. The maximum constant root temperature at which nodules would form was 33�0, and the minimum was in the vicinity of 7�0. The most rapid initial nodulation (2-3 days after inoculation) was observed at 30�0, and plants growing at this temperature had the highest rate of nodule appearance. Below 22�0, there was a marked increase in the "time to first visible nodule" and a general decline in the rate at which they appeared. Differences were observed in the time to first visible nodule, and in the rate of nodule appearance, between different cultivars of T. 8ubterraneum. There was an indication of a temperature X cultivar interaction for these characters. With the three strains of Rh. trifolii used, no differences in their ability to form nodules were observed, although it was known that their subsequent symbiotic behaviour differed under certain root temperature conditions.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation. V. Effect of Time of Exposure to Unfavourable Root Temperatures

1967 ◽  
Vol 20 (6) ◽  
pp. 1105 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Rhizobium Trifolii ◽  
Optimal Temperature ◽  
Three Stages

Symbiotic nitrogen fixation by Trifolium subterraneum L., inoculated with three strains of Rhizobium trifolii Dang., was examined over the range of root temperatures 8-28�0. The plants were transferred from an optimal temperature for nitrogen fixation (23�0) to other temperatures at three stages, namely (1) immediately after inoculation, 3 days after germination, (2) 14 days after germ� ination, when nitrogen fixation had commenced, and (3) 21 days after germination, when the plants had been fixing nitrogen for at least 7 days. Nitrogen increase and dry weight accumulation were determined for two growth periods-days 14-21 (I) and days 21-28 (II)

Growth, Nodulation and Nitrogen Fixation in Stylosanthes: Effect of Different Root Temperatures at two Shoot Temperatures

1989 ◽  
Vol 25 (4) ◽  
pp. 447-460 ◽  
Author(s):  
R. A. Date ◽  
D. Ratcliff
Keyword(s):  
Nitrogen Fixation ◽  
Dry Matter ◽  
Maximum Yield ◽  
Dry Weight ◽  
Strong Interactions ◽  
Root Temperature ◽  
Relative Growth ◽  
Stylosanthes Hamata ◽  
Nitrogen Yields ◽  
Controlled Environments

SUMMARYNodulated plants of Stylosanthes hamata, S. guianensis, S. humilis, S. scabra and S. fruticosa were grown in controlled environments with varied root and shoot temperatures. Measurement of dry matter and nitrogen content suggested that shoot temperature may be more important than root temperature in controlling growth and nitrogen fixation. There were strong interactions with variety. A fall in relative growth rate with increase in shoot temperature was least for S. guianensis and greatest for S. hamata and S. scabra. The optimum root temperature for growth and nitrogen fixation was approximately 30°C. Ninety percent maximum yield was achieved between root temperatures of 15–36°C for growth and 23–34°C for nitrogen fixation but varied with variety. Nitrogen fixation was more sensitive than dry weight to root temperature. The pattern of response of percentage nitrogen and nitrogen fixation efficiency reflected those for dry weight and nitrogen yields. Shoot to root ratios decreased toward the optimum root temperature then increased at the highest temperature. The reaction of varieties to root and shoot temperatures may be an important factor in determining their suitability for new regions.

scholarly journals The structure of ‘ineffective’ nodules and its influence on nitrogen fixation

1940 ◽  
Vol 129 (855) ◽  
pp. 208-229 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Effective Strain ◽  
Infected Tissue ◽  
Especial Reference ◽  
Bean Plants ◽  
Infected Cells ◽  
The Mean ◽  
The Difference

1.The anatomy and cytology of nodules produced on clover, peas and soy beans by 'effective' and 'ineffective' strains of Rhizobia were investigated, with especial reference to the changes in volume of the active infected tissue during the life of the nodule. 2. In clover the mean volume of this active bacterial tissue is about three times as great in 'effective' as in 'ineffective' nodules. This is due to an early arrest of growth in nodules produced by ineffective strains. 3. In all nodules the active bacterial tissue eventually disintegrates, but in effective clover nodules it remains without disintegration for about six times as long as in ineffective nodules. 4. In an experiment to test the nitrogen fixation by clover inoculated with an effective and an ineffective strain, the difference between the strains in the amounts of nitrogen fixed could be accounted for by the differences in volume and in duration of the active bacterial tissue. 5. In peas, nodules produced by an effective strain were nearly twice the length of those produced by an ineffective strain, and their bacterial tissue remained without disintegration for about twice as long. 6. In soy beans the mean volume of bacterial tissue was 4.75 times as great in effective as in ineffective nodules and the percentage of that volume composed of infected cells was twice as great. 7. In ineffective soy bean nodules disintegration of the bacterial tissue began when the plant was 4 weeks old and was practically complete by the twelfth week, at which time no disintegration could be found in effective nodules. 8. The difference in amount of nitrogen fixed by soy bean plants bearing each type of nodule could be accounted for wholly by the factors mentioned above. 9. Thus in both clover and soy bean nodules the volume and duration of the active infected tissue are the main, if not the only, factors determining differences in nitrogen fixation amongst the strains tested.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation VII. Effect of Fluctuating Root Temperature on Nitrogen Fixation

1969 ◽  
Vol 22 (4) ◽  
pp. 839 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Symbiotic Nitrogen Fixation ◽  
Dark Period ◽  
Light Period ◽  
Continuous Illumination ◽  
Continuous Exposure ◽  
Rhizobium Trifolii ◽  
Symbiotic System ◽  
Root Temperature

The effect of exposing nodulated plants to daily periods of high, moderate, or low root temperatures was examined, using Trifolium 8ubterraneum and three strains of Rhizobium trifolii. With strains whose nitrogen fixation was severely retarded by continuous exposure to high root temperatures, the results from treatments involving exposure of 4, 8, 12, and 20 hr/day to 30�C and continuous illumination were consistent with the effect being on the rate of nitrogen fixation, without any permanent impairment to the symbiotic system. With a 12 hr/day light period, a daily 12-hr exposure to 30�C during the dark period reduced total nitrogen fixation as much as exposure to 30�C during the light period. This indicated that the rate of nitrogen fixation during normal dark periods could be as high as that during periods of illumination. Similar conclusions were drawn from the same type of experiments involving daily exposure to moderate (14 and 16�C) root temperatures.

scholarly journals Physical Environment and Symbiotic Nitrogen Fixation

1963 ◽  
Vol 16 (1) ◽  
pp. 28 ◽  
Author(s):  
AH Gibson
Keyword(s):  
Nitrogen Fixation ◽  
Physical Environment ◽  
Symbiotic Nitrogen Fixation ◽  
Trifolium Subterraneum ◽  
Rhizobium Trifolii

The effect of root temperatures (5-30�0) on the growth and symbiotic nitrogen fixation by nodulated plants of four varieties of Trifolium subterraneum L., inoculated with each of two strains of Rhizobium trifolii, was examined.

Growth, Nodulation and Nitrogen Fixation in Stylosanthes: Effect of Different Day/Night Root Temperatures

1989 ◽  
Vol 25 (4) ◽  
pp. 461-472 ◽  
Author(s):  
R. A. Date
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Content ◽  
Constant Temperature ◽  
Dry Matter ◽  
Dry Weight ◽  
Strong Interactions ◽  
Controlled Environment ◽  
Harvest Time ◽  
Root Temperature ◽  
Lower Range

SUMMARYNodulated plants of six varieties of Stylosanthes were grown at a constant temperature of 30°C for 21 days in a controlled environment and then for a further 21 days at a range of day/night root temperatures. Dry matter and nitrogen content of S. hamata cv. Verano and CPI40264A were measured after growth at day/night root temperatures of 30/30, 40/30, 50/30, 60/30 and 60/35°C. Similarly, growth and nitrogen content were measured for Verano, CPI40264A, S. gvianensis cv. Oxley and cv. Cook, S. humilis cv. Lawson and S. scabra cv. Seca after growth at root temperatures of 25/20, 25/25, 30/25, 30/30, 35/30 and 40/30°C. There were strong interactions of root temperature with variety and harvest time (31 and 42 days) but all varieties grew well even at the highest temperatures (50–60°C) provided they were supplied with nitrogen. Symbiotically dependent plants of S. hamata cv. Verano were more tolerant of high root temperatures and maintained better growth and nitrogen fixation at 40/30°C than those of CPI40264A, especially after the 31 day harvest. All six varieties responded similarly, but to differing extents, to the lower range of root temperatures. Nitrogen fixation was more severely affected than dry weight by high root temperature.

Effects of Root Temperature on the Growth and Nitrogen Fixation of Trifolium semipilosum and Trifolium repens

1986 ◽  
Vol 22 (2) ◽  
pp. 133-147 ◽  
Author(s):  
R. A. Date ◽  
R. J. Roughley
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Content ◽  
Dry Matter ◽  
Dry Weight ◽  
Root Systems ◽  
Root Temperature ◽  
Short Term ◽  
Weight Yield ◽  
Short Term Exposure ◽  
Diurnal Temperatures

SUMMARYChanges in plant dry weight and nitrogen content of Trifolium semipilosum cv. Safari and T. repens cv. Grasslands Huia were monitored when the root systems of effectively nodulated 28-day-old plants were exposed to a range of constant and diurnal temperatures for 21 days. Nitrogen fixation was more sensitive to high root temperatures than was dry weight accumulation, and T. semipilosum was relatively more tolerant of high root temperatures than T. repens for both dry weight and nitrogen content. The optimum temperatures for dry weight yield and nitrogen fixation (≡nitrogen content) were similar (21–23°C) for both species.Our data suggest that growth and nitrogen fixation in T. semipilosum are more tolerant of short-term exposure to increase in root temperature than in T. repens. In addition, both species accumulated more dry matter and fixed more nitrogen when night temperatures were reduced from either 30 or 35°C to 25°C. The increase was greater with T. semipilosum and may be a major factor in its adaptation to the humid subtropics and cooler (elevated) tropics.

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