Interactions Between Growth, Phosphate Content and Nitrogen Fixation in Mycorrhizal and Non-Mycorrhizal Medicago sativa

1977 ◽  
Vol 4 (3) ◽  
pp. 403 ◽  
Author(s):  
SE Smith ◽  
MJ Daft
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Nitrogenase Activity ◽  
Mycorrhizal Fungus ◽  
Infection Intensity ◽  
Dry Weight ◽  
Phosphate Content ◽  
Mycorrhizal Infection ◽  
Measured Intensity ◽  
Mycorrhizal Plants

Nodulated Medicago sativa cv. Europe plants, both non-mycorrhizal and mycorrhizal (inoculated with Glomus mosseae), were grown in sand or soil with a range of phosphate levels. The following parameters were measured: intensity of mycorrhizal infection, intensity of nodulation, growth, phosphate content, nitrogenase activity (acetylene reduction) and nitrogen content. Both nodulation and mycorrhizal infection had occurred within 2 weeks of inoculation with the appropriate endophytes. Major increases in dry weight of mycorrhizal plants were not apparent until approximately 10 weeks from inoculation. However, mycorrhizal plants showed more extensive nodulation, coupled with higher rates of nitrogenase activity from 2 weeks onwards, and at the final (12-week) harvest had higher values of % N. Phosphate content of mycorrhizal plants (�g P/g dry wt) was also greater than non-mycorrhizal plants at 7 weeks. By 10 or 12 weeks, when significant mycorrhizal enhancement of growth was apparent, the total nitrogen and total phosphorus per mycorrhizal plant were also higher, but nitrogenase activity and phosphate content measured on a dry weight basis showed no significant differences between mycorrhizal and non-mycorrhizal plants. It is clear that mycorrhizal enhancement of phosphate uptake and nitrogen fixation precedes any effect on growth and the results indicate the importance of the time factor in the development of this tripartite symbiosis between legume, Rhizobium and mycorrhizal fungus.

scholarly journals Influence of Rockphosphate on Root Development and Growth of Strawberry Tips Inoculated with Endomycorrhizae

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 663e-663
Author(s):  
Amal P. de Silva ◽  
W. Keith Patterson
Keyword(s):  
Root Growth ◽  
Root Development ◽  
Glomus Intraradices ◽  
Mycorrhizal Fungus ◽  
Dry Weight ◽  
Mycorrhizal Infection ◽  
Root Dry Weight ◽  
Mycorrhizal Inoculation ◽  
Quadratic Relationship ◽  
Mycorrhizal Plants

Strawberry (Fragaria ×ananasa Duch. `Chandler') tips containing only root initials were inoculated with mycorrhizal fungus Glomus intraradices and were fertilized with rockphosphate levels of 1, 2, 4 and, 6 mg·cm–3 to study root growth and mycorrhizal infection. The addition of rockphosphate at >2 mg·cm–3 decreased mycorrhizal infection. Root dry weight of mycorrhizal strawberry plants increased significantly over the controls with addition of rockphosphate, and mycorrhizal infection significantly decreased the shoot: root ratio. Foliar P levels decreased in mycorrhizal plants fertilized with up to 4 mg·cm–3 of rockphosphate and a quadratic relationship was seen between rockphosphate levels and foliar P. In nonmycorrhizal plants, the highest foliar P level was with rockphosphate at 1 mg·cm–3. The study revealed rockphosphate at 1 to 2 mg·cm–3 is beneficial for greater root growth with mycorrhizal inoculation.

scholarly journals Effect of Mycorrhizal Inoculation on Growth, Nitrogen Fixation and Nutrient Uptake in Alfalfa (Medicago sativa) under Salt Stress

2016 ◽  
Vol 49 (1) ◽  
pp. 67-80 ◽  
Author(s):  
A. Moradi
Keyword(s):  
Nitrogen Fixation ◽  
Salt Stress ◽  
Plant Growth ◽  
Medicago Sativa ◽  
Glomus Mosseae ◽  
Nitrogenase Activity ◽  
Mycorrhizal Fungus ◽  
Am Fungi ◽  
Dry Matter Accumulation ◽  
Mycorrhizal Dependency

AbstractMost legumes in natural conditions form a symbiosis with arbuscular mycorrhizal (AM) fungi. AM fungi in saline soils have been reported to improve salinity tolerance and growth in plants. In the present study, interaction between mycorrhizal fungus,Glomus mosseae, and salinity stress in relation to plant growth, nitrogen fixation, and nutrient accumulation was evaluated in alfalfa (Medicago sativa). Two alfalfa cultivars (Bami and Yazdi) were compared under different levels of salinity with and without mycorrhizal inoculations. Salt stress resulted in a noticeable decline in shoot and root dry matter accumulation, resulting in a decline in the shoot to root ratio (SRR) in all plants. However, Bami was found to be more tolerant to salinity than Yazdi. Inoculated plants exhibited better growth and biomass accumulation under stressed as well as unstressed conditions. Mycorrhizal colonization (MC) was reduced with increasing salinity levels, but the mycorrhizal dependency (MD) increased, which was more evident in Yazdi. Nodulation was completely inhibited under salt stress conditions for both non - AM inoculated alfalfa varieties. Nodulation only occurred in inoculated plants. Nitrogenase activity was reduced with increasing salt concentrations. AM inoculated plants had considerably higher nodule numbers, dry weights, and nitrogenase activity under nonsaline environments. Bami had a comparatively lower Na+concentration and higher K+and Ca2+concentrations than Yazdi. Although nitrogen (N) and phosphorus (P) contents declined with increasing salinity, Bami had higher levels of N and P, as compared with Yazdi. Plants inoculated withGlomus mosseaehad better plant growth and nitrogen fixation under salt stress.

High-temperature-adaptedAzospirillum brasilensestrains: growth and interaction response on associative nitrogen fixation, mineral uptake and yield of cheena (Panicum miliaceumL.) genotypes in calcareous soil

1988 ◽  
Vol 110 (2) ◽  
pp. 321-329 ◽  
Author(s):  
R. Rai
Keyword(s):  
Nitrogen Fixation ◽  
High Temperature ◽  
Calcareous Soil ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Cross Resistance ◽  
Mineral Uptake ◽  
Associative Nitrogen Fixation ◽  
Seed Inoculation ◽  
Resistance To Penicillin

SummaryHigh-temperature-adapted strains RAU 1, RAU 2 and RAU 3 ofAzospirillum brasilenseC 7 were isolated from stepwise transfer to higher temperature (30 to 42 °C). One of the strains (RAU 1) showed more growth, greater nitrogenase and hydrogenase activities at 30 and 42 °C than parental and other temperature-adapted strains. This strain also showed growth and more nitrogenase activity from pH 6·5 to 8·0. Strain RAU 1 showed cross-resistance to penicillin (300/µg/ml) but not to streptomycin, kanamycin, viomycin and polymixin B at 30 and 42 °C. It was demonstrated in field plots in calcareous soil that seed inoculation with RAU 1 enhanced mineral uptake of cheena. Inoculation with RAU 1 led to a significant increase in associative nitrogen fixation, dry weight of roots, grain and straw yield of cheena compared with the uninoculated control with or without applied N, but the effect of seed inoculation with high-temperature-adapted strains was variable with different genotypes of cheena.

scholarly journals Improved tolerance of wheat plants (Triticum aestivum L.) to drought stress and rewatering by the arbuscular mycorrhizal fungus Glomus claroideum: effect on growth and cell membrane stability

2008 ◽  
Vol 20 (1) ◽  
pp. 29-37 ◽  
Author(s):  
José Beltrano ◽  
Marta G. Ronco
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Leaf Chlorophyll ◽  
Severe Water Stress ◽  
Relative Water ◽  
Mycorrhizal Plants ◽  
Total Dry Weight

The aim of this paper was to investigate the contribution of the arbuscular mycorrhizal fungus Glomus claroideum to drought stress tolerance in wheat plants grown under controlled conditions in a growth chamber, and subjected to moderate or severe water stress and rewatering. Water stress tolerance was determined through total dry weight, leaf relative water content, leakage of solutes and leaf chlorophyll and protein concentrations in mycorrhizal and non-mycorrhizal wheat plants. Total dry weight and leaf chlorophyll concentrations were significantly higher in mycorrhizal plants after moderate or severe water stress treatments compared with non-mycorrhizal ones. Electrolyte leakage was significantly lower in water-stressed inoculated plants. Compared to non-inoculated plants, leaf relative water content and total protein concentration of inoculated individuals increased only under severe water stress. When irrigation was re-established, mycorrhizal plants increased their total dry weight and leaf chlorophyll concentration, and recovered cell membrane permeability in leaves compared with non-mycorrhizal plants. In conclusion, root colonization by G. claroideum could be an adequate strategy to alleviate the deleterious effects of drought stress and retard the senescence syndrome in wheat.

scholarly journals EFFETS DES SOUCHES DE RHIZOBIUM MELILOTI ET DES COUPES SUCCESSIVES DE LA LUZERNE (MEDICAGO SATIVA) SUR LA FIXATION SYMBIOTIQUE D’AZOTE

1977 ◽  
Vol 57 (2) ◽  
pp. 433-439 ◽  
Author(s):  
L. M. BORDELEAU ◽  
H. ANTOUN ◽  
R. A. LACHANCE
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Statistical Study ◽  
Symbiotic Nitrogen Fixation ◽  
Rhizobium Meliloti ◽  
Dry Weight ◽  
Indirect Measurement ◽  
Controlled Environment ◽  
Symbiotic Efficiency ◽  
Plant Yield

Symbiotic nitrogen fixation with 49 isolates of Rhizobium meliloti was studied under controlled environment with alfalfa cv. Saranac. It was shown that plant yield in dry weight can be used as an indirect measurement of nitrogen fixation, and as a criterion for selecting efficient strains of R. meliloti. Statistical study on yields of three cuttings has established that the second cutting gives the most necessary information to correctly evaluate the symbiotic efficiency of the isolates. Six very efficient strains were selected.

Studies on associative nitrogen fixation by antibiotic-resistant mutants ofAzospirillum brasilensewith genotypes of lentil (Lens culinaris)Rhizobiumstrains in calcareous soil

1985 ◽  
Vol 104 (1) ◽  
pp. 207-215 ◽  
Author(s):  
R. Rai
Keyword(s):  
Nitrogen Fixation ◽  
Azospirillum Brasilense ◽  
Calcareous Soil ◽  
Lens Culinaris ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Antibiotic Resistant ◽  
Uninoculated Control ◽  
Resistant Mutants ◽  
Antibiotic Resistant Mutants

SummaryNitrosoguanidine-induced mutation frequencies for resistance to streptomycin, spectinomycin, erythromycin and novomycin were studied inAzospirillum brasilense.Lentil inoculated withA. brasilenseand its mutants andRhizobiumstrains produced increased nodule dry weight, nitrogenase activity of nodules and roots and grain yield compared with an uninoculated control.

Bidirectional Selection for Nitrogenase Activity and Shoot Dry Weight Among Late Generation Progenies of a Virginia x Spanish Peanut Cross1

1986 ◽  
Vol 13 (2) ◽  
pp. 86-89 ◽  
Author(s):  
S. Arrendell ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Growth Habit ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Fruit Weight ◽  
Shoot Dry Weight ◽  
Plant Growth Habit ◽  
The Mean ◽  
Selection For

Abstract Improvement of the host contribution to nitrogen fixation has been proposed as a method of increasing nitrogen fixation. Significant variability and generally high broad-sense heritability estimates (.60 ± .27 to .82 ± .26 for nitrogenase activity and .53 ± .29 to .85 ± .26 for shoot dry weight) have been reported for F2-derived families from a cross between the Virginia (Arachis hypogaea L. ssp. hypogaea var. hypogaea) cultivar NC 6 and the Spanish (ssp. fastigiata Waldron vulgaris Harz.) breeding line 922, indicating selection for increased nigtogen fixation should be effective in this population. Lines from this population were chosen randomly from F2-derived families selected for high and low nitrogenase activity and high and low shoot dry weight after evaluation at three dates and two locations in each of 2 years (F5 and F6 generations). This study's objectives were to evaluate the N2-fixing ability of the selected lines and to evaluate the association between plant growth habit and N2 fixation. Twenty-four lines in each of the four selection groups and the parents, NC 6 and 922, were evaluated at two sampling dates and two locations. Mean nitrogenase activity of lines selected for increased nitrogenase activity was significantly greater than the mean of the lines selected for low nitrogenase activity. Improved nitrogenase activity was associated with increased fruit weight. The fruit weight mean of the group selected for increased fruit weight. The fruit weight mean of the group selected for increased nitrogenase activity was 39% greater than the mean of the group selected for low nitrogenase activity. Mean shoot dry weight of lines selected for increased shoot dry weight was significantly greater than the mean of the lines selected for low shoot dry weight; however, the fruit weight means of these two groups did not differ. It was hypothesized that selection for increased N2 fixation in a population derived from a cross between Virginia and Spanish types would eliminate genotypes with Spanish growth habit. Groups selected for high nitrogenase activity and for high shoot dry weight had longer and wider leaflets, longer cotyledonary laterals and greater main stem height than did their respective low selection groups. However, these traits chosen to characterize plant growth habit were inadequate in discriminating parental growth habits. Consequently, the data neither substantiated nor refuted the hypothesis.

Studies on nitrogen fixation by antibiotic-resistant mutants ofAzospirillum brasilenseand their interaction with cheena (Panicum miliaceumL.) genotypes in calcareous soil

1985 ◽  
Vol 105 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. Rai
Keyword(s):  
Nitrogen Fixation ◽  
Calcareous Soil ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Resistant Mutant ◽  
Hydrogenase Activity ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Antibiotic Resistant ◽  
Mutant Strains

SUMMARYAzospirillum brasilense was treated with nitrosoguanidine and five antibiotic-resistant mutant strains isolated. Variations in growth, N2-fixation, ultraviolet-dark survival and level of antibiotic resistance were found between the mutant strains. Mutant strains STR 112 and KR 2051 showed maximum nitrogenase activity, glutamine synthetase activity and hydrogenase activity (H2uptake) at 32 °C and 40 °C respectively. Inoculation of cheena genotypes withA. brasilenseand its mutants led to significant increase in associative nitrogen fixation, dry weight of roots and grain yield compared with the uninoculated control, with significant strains × genotypes interactions in calcareous soil. It was also noted that under laboratory conditionsAzospirilluminoculation may have produced its response by hormonal means and/or associative N2-fixation.

scholarly journals NODULE SENESCENCE AND BIOMASS COMPONENTS IN COMMON BEAN CULTIVARS

2008 ◽  
Vol 31 (3) ◽  
pp. 195
Author(s):  
Fabián Fernández-Luqueño ◽  
David Espinosa-Victoria ◽  
Antonio Munive ◽  
Langen Corlay Chee ◽  
Luis M. Serrano-Covarrubias
Keyword(s):  
Nitrogen Fixation ◽  
Common Bean ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Type I ◽  
Fresh Weight ◽  
Symbiotic Relationships ◽  
Nodule Senescence ◽  
Biomass Components ◽  
Growth Habits

Most legumes establish mutualistic symbiotic relationships with atmospheric nitrogen-fixing bacteria (rhizobia), giving origin to nodules. Nodules exhibit natural or induced aging which coincides with the drop in nitrogenase activity at the flowering period or at the pod filling stage. In this research, the onset of nodule senescence (NS) was evaluated under greenhouse conditions in five common bean (Phaseolus vulgaris L.) cultivars of two growth habits, determined (Type I) and indeterminate (Type III), inoculated with Rhizobium etli CE-3. Weekly destructive samplings were taken to determine nitrogen fixation by the acetylene reduction assay, the number and fresh weight of nodules, as well as root and above ground biomass dry weight. It was found that NS in bean appears to be independent of host plant phenological stage (flowering or pod filling), the longer period the symbiotic system is fixing nitrogen the greater yield is obtained, and that the nodules number and fresh weight are reliable indicators of the nitrogen fixation capacity.

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