Estimating the true cost of dinitrogen fixation by nodulated plants in undisturbed conditions

1983 ◽  
Vol 29 (8) ◽  
pp. 930-937 ◽  
Author(s):  
F. R. Warembourg
Keyword(s):  
Soil Respiration ◽  
Higher Plants ◽  
Dinitrogen Fixation ◽  
Appreciable Amount ◽  
Simultaneous Exposure ◽  
True Cost ◽  
Respiratory Cost

Either symbiotic or nonsymbiotic N2 fixation in association with higher plants requires an appreciable amount of energy. This is mostly supplied by current photosynthesis, but an exact estimation of the true cost of the process is rather difficult. Simultaneous exposure of the association to 14CO2 and 15N2 for 1 day, analysis of labelled CO2 produced by soil respiration, and determination of N2 fixation make it possible to quantify the true respiratory cost associated with fixation. Preliminary trials with soybean suggest an amount of 2.5–7 mg C/mg of N2 fixed.

Ammonia, glutamine, and asparagine: a carbon–nitrogen interface

1988 ◽  
Vol 66 (10) ◽  
pp. 2103-2109 ◽  
Author(s):  
K. W. Joy
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Higher Plants ◽  
Amino Nitrogen ◽  
Glutamate Synthase ◽  
Dinitrogen Fixation ◽  
Similar Function ◽  
Metabolic Processes ◽  
Organic Form ◽  
Primary Input

In plants, the primary input of nitrogen (obtained from the soil or from symbiotic dinitrogen fixation) occurs through the assimilation of ammonia into organic form. Synthesis of glutamine (via glutamine synthetase) is the major, and possibly exclusive, route for this process, and there is little evidence for the participation of glutamate dehydrogenase. A variety of reactions distribute glutamine nitrogen to other compounds, including transfer to amino nitrogen through glutamate synthase. In many plants asparagine is a major recipient of glutamine nitrogen and provides a mobile reservoir for transport to sites of growth; ureides perform a similar function in some legumes. Utilisation of transport forms of nitrogen, and a number of other metabolic processes, involves release of ammonia, which must be reassimilated. In illuminated leaves, there is an extensive flux of ammonia released by the photorespiratory cycle, requiring continuous efficient reassimilation. Aspects of ammonia recycling and related amide metabolism in higher plants are reviewed.

A SPECTROPHOTOMETRIC DETERMINATION OF EXHAUST GAS TEMPERATURES IN THE PULSE-JET ENGINE

1950 ◽  
Vol 28a (4) ◽  
pp. 411-432
Author(s):  
H. F. Quinn
Keyword(s):  
Present Method ◽  
Flame Temperature ◽  
Visible Spectrum ◽  
Black Body ◽  
Small Region ◽  
Black Body Radiation ◽  
Appreciable Amount ◽  
Jet Engine ◽  
Pulse Jet

This paper describes a spectrophotometric method whereby instantaneous values of a variable flame temperature, in the particular case of nonluminous flames, may be determined and continuously recorded.This new technique, which depends upon the establishment of monochromatic black-body radiation conditions in the flame for a small region in the visible spectrum, involves the continuous measurement of radiation intensity in the above region, the intensity being, thereafter, correlated with the temperature of the flame.The problem of temperature measurement in the general case of nonluminous flames (flames which do not contain an appreciable amount of free carbon in the form of soot) is considered and a brief review of previous techniques employed for this purpose over the past 50 years is given. The basic theory and preliminary experimental justification of the present method are discussed.A description of the apparatus and the experimental arrangement used by the author in a specific application of the present method in the determination of the time variation of temperature in the exhaust flame of a pulse-jet engine is given. This includes details of a special type of spectrophotometer which employs a multiplier photocell as the radiation detecting and measuring element and, also, a "black-body" cavity constructed as a standard radiation source for the calibration of the former instrument. An original technique used to investigate the emissivity of flames colored by alkali metal vapors is described and its application to the present problem shown.Finally, the measurable temperature range of the present apparatus is considered together with the inherent limitations of the new method.

A reappraisal of the use of DMSO for the extraction and determination of chlorophylls a and b in lichens and higher plants

1992 ◽  
Vol 32 (2) ◽  
pp. 85-100 ◽  
Author(s):  
J.D. Barnes ◽  
L. Balaguer ◽  
E. Manrique ◽  
S. Elvira ◽  
A.W. Davison
Keyword(s):  
Higher Plants ◽  
Chlorophylls A And B

Heredity and Dermal Patterns in the Interdigital Areas of the Palm

1965 ◽  
Vol 14 (3) ◽  
pp. 295-304 ◽  
Author(s):  
Edward V. Glanville
Keyword(s):  
Relative Position ◽  
Monozygotic Twins ◽  
Correlation Coefficients ◽  
Appreciable Amount ◽  
Pedigree Data ◽  
Ridge Count ◽  
Hereditary Factors ◽  
Dominance Variation ◽  
Additive Genes

SUMMARYHereditary factors involved in the determination of the size, relative position and type of pattern formed by the dermal ridges in the interdigital areas of the palm have been investigated by means of twin and family studies. The sample consisted of 566 individuals of European descent. The ridge-counts of patterns in the interdigital areas were determined. Correction factors were introduced to compensate for different average counts in each interdigital area. The correlation coefficients between family relatives were calculated using the ridge-counts. The coefficient for monozygotic twins was .88±.04 and for parent and child from .346 to .425 and for sib pairs from .328 to .412. There was no evidence of sex-linkage or of the effects of dominance. Variation appeared to be determined by additive genes but an appreciable amount of variation of non-genetic origin was observed. Bilateral asymmetry in the ridge-count, type of pattern and relative position of the patterns was evident. Concordance rates in twins and other family members and pedigree data provided further evidence of hereditary influence in the determination of the position and type of pattern in the interdigital areas.

Phosphorus Compounds of Milk. V. The Phosphorus Partition in Milk, with Preliminary Observations on Milk Phosphatase

1933 ◽  
Vol 5 (1) ◽  
pp. 54-62 ◽  
Author(s):  
W. R. Graham ◽  
H. D. Kay
Keyword(s):  
Phosphorus Compounds ◽  
Appreciable Amount ◽  
Cow’S Milk ◽  
Inorganic P ◽  
Cow's Milk ◽  
Holstein Friesian ◽  
P Content ◽  
Mammalian Tissues ◽  
Jersey Cows

1. Using the method described by Sanders for protein and fat precipitation from cow's milk, a fairly satisfactory method of determining the phosphorus partition in cow's milk has been devised.2. It is found that the gravimetric procedure of the American Association of Official Agricultural Chemists ((10), p. 3), which was not, in any case, specifically recommended for the analysis of milk, cannot be applied with safety to the determination of inorganic phosphate in filtrates prepared by Sanders' (1932) method, and that the conclusion that there is no appreciable amount of organically combined phosphorus in these filtrates is therefore invalidated.3. The ester P (organically combined, acid-soluble P) in milk obtained by the usual milking routine varies from 1/7 to 1/4 of the inorganic P of the milk (from 7 to 21 mg. P per 100 c.c. milk).4. An active phosphatase is present in cow's milky, and brings about changes in the ester P content of the milk on standing, possibly within and certainly without the mammary gland. Like phosphatases of all mammalian tissues, its optimum pH is in the neighbourhood of 9·0. In freshly drawn milk it is working, therefore, considerably on the acid side of its optimum.5. The phosphoric ester P of the milk appears to vary with the breed of cow, being low in the miiy of Canadian Holstein-Friesian cows and higher in that of Jersey cows.

Regulation of tetrapyrrole biosynthesis in higher plants

2005 ◽  
Vol 33 (4) ◽  
pp. 737-742 ◽  
Author(s):  
M. Moulin ◽  
A.G. Smith
Keyword(s):  
Higher Plants ◽  
Accurate Method ◽  
Control Points ◽  
Branch Points ◽  
Tetrapyrrole Biosynthesis ◽  
The Earth ◽  
Porphyrin Macrocycle ◽  
End Products ◽  
Strong Competition

Plant tetrapyrroles are the most abundant biomolecules on the earth and are cofactors of many apoproteins essential for plant function. The four end-products sirohaem, chlorophyll, haem and phytochromobilin are synthesized by a common branched pathway, which is tightly regulated to ensure a continuous supply to the cognate apoproteins. This may induce strong competition between different branches of the pathway for common substrates. In addition, the intermediates, which are phototoxic, must not be allowed to accumulate in the cell. The major control points are during the synthesis of the initial precursor, ALA (5-aminolaevulinic acid), and at the branch points for the insertion of metal ions into the porphyrin macrocycle. A recent study has also suggested that tetrapyrroles are involved in the communication between the chloroplast and the nucleus, strengthening the necessity for tight regulation. However, intermediates remain difficult to quantify mainly due to their low content and the different properties of the intermediates. In this paper, we summarize the regulation of this pathway and we detail why it is important to have an accurate method for the determination of tetrapyrroles in plants.

scholarly journals Effect Of Environmental Load On The Toxicity Of Bottom Sediments

2015 ◽  
Vol 14 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Oľga Šestinová ◽  
Lenka Findoráková ◽  
Silvia Dolinská ◽  
Jozef Hančuľák ◽  
Tomislav Špaldon ◽  
...  
Keyword(s):  
Higher Plants ◽  
River Sediments ◽  
Water Reservoir ◽  
Total Mortality ◽  
Environmental Load ◽  
Study Materials ◽  
Phytotoxic Effect ◽  
Ecotoxicity Tests ◽  
Plant Test

Abstract This study is devoted to Ecotoxicity tests, Terrestrial Plant Test (modification of OECD 208), Phytotoxkit microbiotest on Sinapis alba and chronic tests of Earthworm (Eisenia veneta), modification of OECD Guidelines for the testing of chemicals 317, Bioaccumulation in Terrestrial Oligochaetes on polluted sediments. Earthworms can accelerate the removal of contaminants from soil. The study materials are river sediments, which were obtained from a monitoring station - the Water reservoir the Ružín No.1 particularly, the river Hornád, Hnilec and sample from sludge bed Rudňany. The samples of sediment were used to assess of the potential phytotoxic effect of heavy metals on higher plants. Total mortality was established in earthworms using chronic toxicity test after 7 and 28 exposure days. Based on the phytotoxicity testing, phytotoxic effects of the metals contaminated sediments from the sludge bed Rudňany on S. alba seeds was observed. The largest concentration differences were recorded in the sample R7 after 7 days earthworms exposure. The earthworms mortality was not influenced by sediment neither after 7 nor 28 exposure days The spectra of samples H, HO and R showed broad peak at 1 419 - 1 512 cm−1 characteristic for carbonate radical. In the spectra of the samples (R and R7) the vibration of C-H groups at 2 926 and 2 921 cm−1, respectively were also observed, demonstrating the presence of organic matter. Our research will continue with determination of metals concentration in earthworms.

Sign in / Sign up

Export Citation Format

Share Document