scholarly journals Studies on nitrogenase activity of diazotrophic isolates from different rice production systems

2016 ◽  
Vol 8 (1) ◽  
pp. 284-289
Author(s):  
S. Kanimoli ◽  
K. Kumar
Keyword(s):  
Acetylene Reduction ◽  
Tamil Nadu ◽  
Production Systems ◽  
Nitrogenase Activity ◽  
Rice Production ◽  
Lowland Rice ◽  
Aerobic Rice ◽  
Marked Variation ◽  
Reduction Assay ◽  
First Time

The present study was carried out to evaluate the nitrogen fixing ability of diazotrophs isolated from the rhizosphere soils of rice which were grown in three different rice growing systems. A total of hundred and ten isolates obtained were subjected to Acetylene Reduction Assay (ARA) and ninety eight isolates recorded significant amount of nitrogenase activity in a range of 185.73 to 3794.55 nmoles of ethylene mg of protein-1 h-1. The highest nitrogenase activity was recorded by Derxia (3794.55 nmoles of ethylene mg of protein-1 h-1) isolated from Trichy (lowland). Among the three different rice production systems, isolates obtained from lowland rice (Derxia – 3794.5 nmoles of ethylene mg of protein-1 h-1) recorded higher nitrogenase activity followed by Aerobic (Pseudomonas - 2194.89 nmoles of ethylene mg of protein-1 h-1) and SRI (Azotobacter - 1971.85 nmoles of ethylene mg of protein-1 h-1) rice isolates. The results revealed marked variation in the ARA of the diazotrophic isolates obtained from lowland, SRI and Aerobic rice. The nitrogenase activity of diazotrophs from rice fields have been reported earlier but the nitrogenase activity of diazotrophs from three different rice production systems from various parts of Tamil Nadu is reported for the first time from India.

scholarly journals Factors Influencing Nitrogenase Activity (Acetylene Reduction) by Root Nodules of Groundnut, Arachis hypogaea L.

1983 ◽  
Vol 10 (1) ◽  
pp. 26-29 ◽  
Author(s):  
P. T. C. Nambiar ◽  
P. J. Dart
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Activity Period ◽  
Diurnal Fluctuation ◽  
Factors Influencing ◽  
Arachis Hypogaea L ◽  
Reduction Assay

Abstract Acetylene reduction assay, used to measure nitrogenase activity of legume root nodules, is influenced by environmental factors, which limit its application. The effects of some of the environmental factors on acetylene reduction by groundnut root nodules are described. The activity was nonlinear during the first hour of incubation. Assay temperature above 25 C decreased the activity. Washing the nodulated roots prior to the assay also decreased the activity. The activity was influenced by light intensity, soil moisture, and moisture content in the incubation bottle. Diurnal fluctuation with one maximum and one minimum activity period during a 24 hour cycle was observed. Nitrogenase activity was higher during the postrainy season compared to that of the rainy season. A virginia cultivar Kadiri-71 had higher nitrogenase activity than a dwarf valencia cultivar, MH 2.

scholarly journals QTL Validation and Development of SNP-Based High Throughput Molecular Markers Targeting a Genomic Region Conferring Narrow Root Cone Angle in Aerobic Rice Production Systems

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2099
Author(s):  
Ricky Vinarao ◽  
Christopher Proud ◽  
Peter Snell ◽  
Shu Fukai ◽  
Jaquie Mitchell
Keyword(s):  
Production Systems ◽  
Genotypic Variation ◽  
Cone Angle ◽  
Genomic Region ◽  
Rice Production ◽  
Aerobic Rice ◽  
Breeding Programs ◽  
Qtl Validation ◽  
Specific Pcr ◽  
Kasp Markers

Aerobic rice production (AP) provides potential solutions to the global water crisis by consuming less water than traditional permanent water culture. Narrow root cone angle (RCA), development of deeper rooting and associated genomic regions are key for AP adaptation. However, their usefulness depends on validation across genetic backgrounds and development of linked markers. Using three F2 populations derived from IRAT109, qRCA4 was shown to be effective in multiple backgrounds, explaining 9.3–17.3% of the genotypic variation and introgression of the favourable allele resulted in 11.7–15.1° narrower RCA. Novel kompetitive allele specific PCR (KASP) markers were developed targeting narrow RCA and revealed robust quality metrics. Candidate genes related with plant response to abiotic stress and root development were identified along with 178 potential donors across rice subpopulations. This study validated qRCA4′s effect in multiple genetic backgrounds further strengthening its value in rice improvement for AP adaptation. Furthermore, the development of novel KASP markers ensured the opportunity for its seamless introgression across pertinent breeding programs. This work provides the tools and opportunity to accelerate development of genotypes with narrow RCA through marker assisted selection in breeding programs targeting AP, which may ultimately contribute to more sustainable rice production where water availability is limited.

The effect of four new Frankia isolates on growth and nitrogenase activity in clones of Alnusrubra and Alnussinuata

1984 ◽  
Vol 14 (5) ◽  
pp. 701-706 ◽  
Author(s):  
Carolyn V. Carpenter ◽  
Linda R. Robertson ◽  
John C. Gordon ◽  
David A. Perry
Keyword(s):  
Plant Growth ◽  
Acetylene Reduction ◽  
Growth Parameters ◽  
Nitrogenase Activity ◽  
National Forest ◽  
Root Weight ◽  
Stem Height ◽  
Host Genotype ◽  
Red Alder ◽  
Reduction Assay

Two clones of red alder (Alnusrubra Bong) and two clones of Sitka alder (Alnussinuata (Regel) Rydb) were inoculated with four new Frankia isolates. The endophytes included a red and a Sitka alder isolate from Vancouver Island, British Columbia, and a red and a Sitka alder isolate from Mount Hood National Forest, Oregon. All inoculated ramets were well nodulated and had an active nitrogenase system as measured by the acetylene reduction assay. For the inoculated red alder clones, host genotype had a significant effect on stem height and root weight. None of the growth parameters was affected by endophyte strain or by clone–endophyte interaction. For Sitka alder clones, host genotype affected all growth variables. While endophyte strain had no effect on plant growth, clone–endophyte interaction occurred with stem height and leaf weight. Conversely, acetylene reduction values were not affected by clone or clone–endophyte interaction in either species. In red alder, acetylene reduction values were significantly affected by endophyte strain showing both inter- and intra-species variations. In Sitka alder, endophyte strain did not affect acetylene reduction values. The results indicate that both host genotype and endophyte may affect the efficiency of host–endophyte symbioses.

Nitrogenase Activity and Associated Carbon Budgets in Seedlings of Acacia mangium Measured With a Flow-Through System of the Acetylene Reduction Assay

1992 ◽  
Vol 19 (2) ◽  
pp. 97 ◽  
Author(s):  
JS Sun ◽  
RJ Simpson ◽  
R Sands
Keyword(s):  
Acetylene Reduction ◽  
Root Respiration ◽  
Nitrogenase Activity ◽  
Acacia Mangium ◽  
Maintenance Respiration ◽  
Carbon Cost ◽  
Gas System ◽  
Reduction Assay ◽  
Flow Through ◽  
Nodulated Root

Following introduction of acetylene into the flow-through gas system, nitrogenase activity of young seedlings of Acacia mangiurn Willd. increased during the initial gas mixing period but declined thereafter. Nitrogenase-linked respiration also declined rapidly for 3-4 min and slowly thereafter following introduction of acetylene. Seedlings of 12-42 weeks showed a decline in nitrogenase-linked respiration of 15-40%. Nitrogenase activity and nodulated root respiration declined further when the oxygen concentration in the gas flowing past the nodules was reduced. These concomitant declines in nodulated root respiration and nitrogenase activity were used to explore the relation between nodulated root respiration and nitrogenase activity, and to provide an estimate of the carbon cost of nitrogenase activity, and the growth and maintenance respiration of nodulated roots. The carbon cost of nitrogenase activity was 2-8 μmol CO2 μmol-1 C2H2 reduced for young seedlings (12-20 weeks) and was lower (1.3) for older seedlings (30-42 weeks). Nitrogenase activity was 1.2 μmol C2H4 g-1 nod. dw min-1 for plants at 12 weeks, but was 0.3 μmol C2H4 g-1 nod. dw min-1 for plants at 42 weeks after transplanting. The proportion of nitrogenase-linked respiration in nodulated root respiration also declined rapidly with plant age, being 70% at 12 weeks and only 6% at 42 weeks after transplanting.

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