Effects of Fire on the Growth, Nutrient Content and Rate of Nitrogen Fixation of the Cycad Macrozamia riedlei

1980 ◽  
Vol 28 (3) ◽  
pp. 271 ◽  
Author(s):  
TS Grove ◽  
AM O'connell ◽  
N Malajczuk
Keyword(s):  
Nitrogen Fixation ◽  
Forest Ecosystem ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Leaf Growth ◽  
Nutrient Content ◽  
Nitrogen And Phosphorus ◽  
Eucalyptus Marginata ◽  
Plant Parts ◽  
Coralloid Roots

The response of Macrozamia riedlei(Gaud.) C.A. Gardn. to fire, and its contribution to the input of nitrogen to the jarrah (Eucalyptus marginata Donn ex Sm.) forest ecosystem of south-western Australia, were studied by measuring the biomass and nutrient content of plant parts, and the nitrogenase activity of coralloid roots, in relation to time since burning. Leaf growth was rapid during the first year following fire. In forest burnt 1-5 years previously, the ratio of weight of leaves to weight of bole did not differ significantly between sites. On a site burnt 7 years previously a reduced proportion of leaves in the total plant biomass was attributed to a yellowing and senescence of leaves. The ratio of weight of coralloid roots to weight of boles was greatest on the most recently burnt site. Concentrations of nitrogen and phosphorus in leaves, and phosphorus, potassium and zinc in coralloid roots, were significantly higher in plants growing in recently burnt forest. Concentrations of calcium, sodium and chlorine in leaves were higher on sites which had not been burnt recently. The rate of acetylene reduction, expressed per unit of bole weight, was greatest where forest had been burnt 1 year before sampling and decreased to a minimum where burning had occurred 7 years previously. This trend resulted from a decrease in both the weight and nitrogenase activity of coralloid roots with increasing time since burning. Estimated rates of nitrogen fixation were 8.4 and 1.4 kg ha-1 year-1 on sites burnt 1 . 5 and 7 years previously. In the period between successive prescribed burns (5 to 7 years), M. riedlei was estimated to fix c. 35 kg nitrogen ha-1. This appears to be a significant input in relation to the nitrogen balance of the jarrah forest ecosystem.

scholarly journals The effect of inoculation of pea plants with mycorrhizal fungi and Rhizobium on nitrogen and phosphorus assimilation

2011 ◽  
Vol 52 (No. 10) ◽  
pp. 435-440 ◽  
Author(s):  
M. Geneva ◽  
G. Zehirov ◽  
E. Djonova ◽  
N. Kaloyanova ◽  
G. Georgiev ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Mycorrhizal Fungi ◽  
Glomus Mosseae ◽  
Rhizobium Leguminosarum ◽  
Glomus Intraradices ◽  
Plant Biomass ◽  
Phosphorus Level ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity

The study evaluated the response of pea (Pisum sativum cv. Avola) to arbuscular mycorrhizal fungi (AM) species Glomus mosseae and Glomus intraradices and Rhizobium leguminosarum bv. viceae, strain D 293, regarding the growth, photosynthesis, nodulation and nitrogen fixation activity. Pea plants were grown in a glasshouse until the flowering stage (35 days), in 4 kg plastic pots using leached cinnamonic forest soil (Chromic Luvisols – FAO) at P levels 13.2 (P1) and 39.8 (P2) mg P/kg soil. The obtained results demonstrated that the dual inoculation of pea plants significantly increased the plant biomass, photosynthetic rate, nodulation, and nitrogen fixation activity in comparison with single inoculation with Rhizobium leguminosarum bv. viceae strain D 293. On the other hand, coinoculation significantly increased the total phosphorus content in plant tissue, acid phosphatase activity and percentage of root colonization. The effectiveness of coinoculation with Rhizobium leguminosarum and Glomus mosseae was higher at the low phosphorus level while the coinoculation with Glomus intraradices appeared to be the most effective at higher phosphorus level.

scholarly journals Nitrogen Fixation in the Coralloid Roots of Macrozamia Communis L. Johnson

1965 ◽  
Vol 18 (6) ◽  
pp. 1135 ◽  
Author(s):  
FJ Bergersen ◽  
GS Kennedy ◽  
W Wittmann
Keyword(s):  
Nitrogen Fixation ◽  
Green Algae ◽  
Intact Plant ◽  
Large Excess ◽  
Fixed Nitrogen ◽  
Blue Green Algae ◽  
Plant Parts ◽  
Isotopic Method ◽  
Coralloid Roots

Coralloid roots of Macrozamia communis have been shown by the isotopic method to fix nitrogen when they contain the endophytic blue�green algae. Immature coralloid roots devoid of the endophyte did not fix nitrogen. Coralloid roots from glasshouse-grown plants fixed 2� 7 times as much nitrogen when illuminated than they did in the dark and the IfiN excess was about equally divided between fractions soluble or insoluble in 3N HCI. Coralloid roots excavated from beneath large fieldgrown plants were opaque and did not fix more nitrogen when illuminated than they did in the dark. Most of the newly fixed nitrogen was found in the buffered sucrose extract of crushed tissue. When an intact plant bearing coralloid roots was exposed to an atmosphere containing a large excess of IfiN. for 48 hr the IfiN was found to be distributed through the plant parts. Nitrogen fixed in the coralloid roots is thus available for the growth of the plant. The coralloid roots evolved small amounts of hydrogen.

The development of cuttings of the Washington navel orange to the stage of fruit set. II. Drifts in nutrient composition

1961 ◽  
Vol 12 (6) ◽  
pp. 1066
Author(s):  
CT Gates ◽  
D Bouma ◽  
H Groenewegen
Keyword(s):  
Phosphorus Content ◽  
Fruit Set ◽  
Dry Weight ◽  
Nutrient Content ◽  
Rhythmic Pattern ◽  
Nitrogen And Phosphorus ◽  
Nutrient Distribution ◽  
Plant Parts ◽  
Washington Navel ◽  
Low Phosphorus

Changes in nutrient content with time, especially of nitrogen and phosphorus content, are presented and are considered in relation to the results for dry weight reported previously. It was found that drifts in nitrogen and phosphorus with time were complementary to the pattern for dry weight noted earlier. The distribution of these nutrients to the developing plant followed a like rhythmic pattern of alternate distribution to shoot and root. There appeared to be no build up of nutrient to trigger off developing of new shoots, and at all times nutrient distribution was preferentially to younger developing parts. Low phosphorus supply caused a lowering of both relative and absolute contents of phosphorus and nitrogen in all plant parts. The pattern of development was not greatly altered in character by low phosphorus but was delayed. All vegetative parts responded similarly in control and low phosphorus plants, and the younger parts did not appear to dominate the older in development. In this regard, the pattern of growth seemed to differ from that of many annuals. The proportion of tissue potassium was lowered and that of calcium raised by ammonium as the source of nitrogen. A concomitant effect on phosphorus and nitrogen metabolism was noted.

scholarly journals Forest Soil Bacteria: Diversity, Involvement in Ecosystem Processes, and Response to Global Change

2017 ◽  
Vol 81 (2) ◽  
Author(s):  
Salvador Lladó ◽  
Rubén López-Mondéjar ◽  
Petr Baldrian
Keyword(s):  
Global Change ◽  
Forest Soil ◽  
Forest Soils ◽  
Forest Ecosystem ◽  
Mycorrhizal Fungi ◽  
Soil Bacteria ◽  
Plant Biomass ◽  
Ecosystem Processes ◽  
N Fixation ◽  
Nitrogen And Phosphorus

SUMMARY The ecology of forest soils is an important field of research due to the role of forests as carbon sinks. Consequently, a significant amount of information has been accumulated concerning their ecology, especially for temperate and boreal forests. Although most studies have focused on fungi, forest soil bacteria also play important roles in this environment. In forest soils, bacteria inhabit multiple habitats with specific properties, including bulk soil, rhizosphere, litter, and deadwood habitats, where their communities are shaped by nutrient availability and biotic interactions. Bacteria contribute to a range of essential soil processes involved in the cycling of carbon, nitrogen, and phosphorus. They take part in the decomposition of dead plant biomass and are highly important for the decomposition of dead fungal mycelia. In rhizospheres of forest trees, bacteria interact with plant roots and mycorrhizal fungi as commensalists or mycorrhiza helpers. Bacteria also mediate multiple critical steps in the nitrogen cycle, including N fixation. Bacterial communities in forest soils respond to the effects of global change, such as climate warming, increased levels of carbon dioxide, or anthropogenic nitrogen deposition. This response, however, often reflects the specificities of each studied forest ecosystem, and it is still impossible to fully incorporate bacteria into predictive models. The understanding of bacterial ecology in forest soils has advanced dramatically in recent years, but it is still incomplete. The exact extent of the contribution of bacteria to forest ecosystem processes will be recognized only in the future, when the activities of all soil community members are studied simultaneously.

scholarly journals Utilization of the biological nitrogen fixation for soil evaluation

2011 ◽  
Vol 49 (No. 8) ◽  
pp. 359-363 ◽  
Author(s):  
T. Šimon
Keyword(s):  
Nitrogen Fixation ◽  
Field Experiments ◽  
Symbiotic Nitrogen Fixation ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Farmyard Manure ◽  
Soil Samples ◽  
Soil Evaluation ◽  
Biological Nitrogen

Non-symbiotic nitrogen fixation (potential nitrogenase activity – PNA) of soil samples originating from different plots of long-term field experiments (selected variants: Nil, NPK [mineral fertilisation: 64.6–100 kg N/ha/year], FYM [farmyard manure], and FYM + NPK from three blocks III, IV and B with different crop rotation) was determined in laboratory experiments. The symbiotic nitrogen fixation (total nitrogenase activity – TNA) of the same soil samples was evaluated in hydroponic experiments with pea (2001, 2002) and lucerne (2001) in which the soil samples were used as a natural inoculum. The high values of PNA were found in the variants fertilised with FYM in all three blocks and all experiments. Simultaneously, the variants fertilised with mineral NPK reached low values of PNA. The farmyard manuring enhanced the number of free-living bacteria Azotobacter spp. that were identified in all soil samples. In the hydroponic experiments with pea, the highest nonsignificant values of TNA were found in variants B 284 (FYM + NPK) and III 254 (FYM + NPK) in 2001, and B 214 (FYM) and III 214 (FYM) in 2002. Plants inoculated with soil from these variants formed also high amounts of nodules (significant differences in block IV in 2001) and plant biomass. In the experiments with lucerne, the nonsignificantly highest TNA values were found in variant III 154 (NPK). Variants from block III (214, 254) and IV (114 and 154) showed the nonsignificantly lowest TNA values. The rhizobia that effectuate symbiosis with pea were more active in the soil samples in 2001 than those forming nodules on lucerne.

scholarly journals Alpine meadow degradation depresses soil nitrogen fixation by regulating plant functional groups and diazotrophic community composition

2021 ◽  
Author(s):  
Lu Zhang ◽  
Xiangtao Wang ◽  
Jie Wang ◽  
Lirong Liao ◽  
Shilong Lei ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Functional Groups ◽  
Community Composition ◽  
Alpine Meadow ◽  
Plant Biomass ◽  
Nutrient Content ◽  
Plant Functional Groups ◽  
Alpine Meadow Degradation ◽  
Diazotrophic Community ◽  
Meadow Degradation

Abstract Aims Biological nitrogen fixation (BNF), a function performed by diazotrophic microbes, plays an essential role in nitrogen (N) bioavailability in terrestrial ecosystems. However, little is known about the effects of degradation on soil BNF and diazotrophic communities in alpine meadow. Methods We investigated the changes in soil BNF and their potential drivers in alpine meadows along a degradation gradient on the Tibetan Plateau (non-degraded, lightly degraded, moderately degraded, and severely degraded meadows) using real-time quantitative PCR and amplicon sequencing. Results Soil BNF rates decreased significantly along the meadow degradation gradient with a range of 17.34–79.84 nmol C2H4 g− 1 dry soil d− 1 across all sites. The highest BNF was observed in the non-degraded meadow and was 1.5–4.6-fold higher than that in degraded meadows. Meadow degradation significantly reduced the gene abundance of nifH and the Shannon and Chao1 diversity indices of diazotrophs, accompanied by a decrease in plant biomass, soil moisture, and nutrient content (C, N component). Soil BNF potential was closely correlated with plant biomass, soil nutrient content, and diazotrophic abundance (including Nostoc, Scytonema, Rhodopseudomonas, Rhizobiales, and Proteobacteria). The community composition of diazotrophs differed markedly among sites with different levels of degradation, and both autotrophic (Cyanobacteria) and heterotrophic (Proteobacteria) diazotrophs contributed simultaneously to the BNF. The plant functional groups, especially the sedges family, were the primary drivers for soil BNF rates via mediating soil moisture, nutrient level (dissolved organic C and N), nifH gene abundance, and diazotrophic community composition. Conclusions Our results reveal the underlying mechanism of changes in soil BNF during alpine meadow degradation, emphasize the importance of plant functional groups in shaping the diazotrophic community and BNF potential, and provide insights for the restoration of degraded meadow ecosystems.

scholarly journals Efficiency of Recycled Biogas Digestates as Phosphorus Fertilizers for Maize

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 553
Author(s):  
Inga-Mareike Bach ◽  
Lisa Essich ◽  
Torsten Müller
Keyword(s):  
Biomass Production ◽  
Plant Biomass ◽  
Nutrient Content ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Phosphorus Fertilizers ◽  
Future Supply ◽  
Application Techniques ◽  
Phosphorus Recycling ◽  
Fertilizing Effect

Despite phosphorus resources on Earth being limited, over fertilization in many agricultural situations causes significant resource consumption. Phosphorus-recycling within agricultural production can reduce global dilution into the environment and is thus essential to secure sustainable future supply. This study investigated the fertilization efficacy of phosphorus fertilizers recycled from biogas digestates in maize shoots grown under controlled greenhouse conditions, in two soils, in a pot experiment. Variables investigated were plant-available phosphorus in soil, plant biomass production, and concentration of phosphorus, calcium, and magnesium in shoots. Soils were treated with three different fertilizer fractions, separated from biogas digestates, at equivalent phosphorus concentrations, using different combinations and application techniques, isolated or in combination, and compared to triple superphosphate (TSP) as a reference. One of the fractions (P-Salt) had effects on biomass production and plant phosphorus concentration equivalent to TSP in agricultural surface soil. In the second soil (with less active soil life and nutrient content), equivalence to TSP was achieved with combinations of two recycled fractions (P-Salt and dried solids). The enhancement of the phosphorus fertilizing effect by the solids was synergistic, indicating that the solids had a soil conditioning effect. The results show that biogas digestates are a valuable source for phosphorus recycling of fractions that have equivalent or even superior fertilizing properties compared to TSP.

scholarly journals Organic Materials and Their Chemically Extracted Humic and Fulvic Acids as Potential Soil Amendments for Faba Bean Cultivation in Soils with Varying CaCO3 Contents

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 205
Author(s):  
Ihab M. Farid ◽  
Mohamed A. El-Ghozoli ◽  
Mohamed H. H. Abbas ◽  
Dalia S. El-Atrony ◽  
Hassan H. Abbas ◽  
...  
Keyword(s):  
Humic Substances ◽  
Faba Bean ◽  
Plant Biomass ◽  
Nitrogenase Activity ◽  
Organic Amendments ◽  
Fulvic Acids ◽  
Mineral N ◽  
Randomized Design ◽  
Long Time ◽  
Factor C

Organic amendments are important sources of nutrients that release upon organic matter degradation, yet the stability of these organics in arid and semi-arid regions is relatively low. In contrast, humic substances (HS) are resistant to biodegradation and can keep nutrients in the soil available for the plant over a long time. Combinations between humic substances (HS) and mineral-N fertilizers are assumed to retain higher available nutrients in soils than those recorded for the sole application of either mineral or organic applications. We anticipate, however, that humic substances might not be as efficient as the organics from which they were extracted in increasing NP uptake by plants. To test these assumptions, faba bean was planted in a pot experiment under greenhouse conditions following a complete randomized design while considering three factors: two soils (calcareous and non-calcareous, Factor A), two organics (biogas and compost, Factor B) and combinations of the organics and their extracts (HA or FA) together with complementary doses of mineral-N ((NH4)2SO4) to attain a total rate of 50 kg N ha−1 (the recommended dose for faba bean plants) (Factor C). Results indicated that nitrogenase activity increased significantly due to the application of the used organics. In this respect, compost manure caused higher nitrogenase activity than biogas manure did. Humic substances raised NP-availability and the uptake by plants significantly; however, the values of increase were lower than those that occurred due to the compost or biogas manure. Moreover, the sole application of the used organics recorded the highest increases in plant biomass. Significant correlations were also detected between NP-availability, uptake and plant biomass. This means that HS could probably retain nutrients in available forms for long time periods, yet nutrients released continuously but slowly upon decomposition of organics seemed more important for plant nutrition.

scholarly journals Leaf Nutrient Relations of Cycads in a Common Garden

2021 ◽  
Vol 14 ◽  
pp. 194008292110365
Author(s):  
Thomas E. Marler ◽  
Anders J. Lindström
Keyword(s):  
Common Garden ◽  
Nutrient Content ◽  
Leaf Traits ◽  
Botanical Garden ◽  
Active Management ◽  
Nitrogen And Phosphorus ◽  
Representative Species ◽  
Nutrient Relations ◽  
Homogeneous Environment ◽  
Dry Combustion

Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.

Studies on compatibility of nitrogen fixation by high-temperature-adapted Rhizobium strains and Vigna radiata genotypes at two moisture levels in calcareous soil

1983 ◽  
Vol 101 (2) ◽  
pp. 377-381 ◽  
Author(s):  
R. Rai ◽  
V. Prasad
Keyword(s):  
Nitrogen Fixation ◽  
High Temperature ◽  
Grain Yield ◽  
Vigna Radiata ◽  
Calcareous Soil ◽  
Nitrogenase Activity ◽  
Summer Season ◽  
Green Gram ◽  
Rhizobium Strains

SUMMARYRhizobium strains adapted to high temperature, and genotypes of green gram, were used to study the symbiotic N2-fixation in a summer season at two moisture levels in calcareous soil. Different interactions between strains and genotypes were observedatthe two moisture levels. At both moisture levels, strain S4 with the green gram genotype S8 showed the greatest grain yield, nitrogenase activity, leghaemoglobin and ethanolsoluble carbohydrate of nodules.

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