Intervarietal Differences in the Amino Acid Composition of Pea Roots as Related to their Response to Salinity

The salt tolerance of three cultivars of Pisum sativum L. asdefined by root growth on saline substrate was in the orderDan > Alaska > Laxton Progress. The total content of freeamino acids decreased in Alaska, but not in Laxton Progress,with increasing salinity, while the content of the free basicamino acids increased with salinity. In both cultivars salinityinduced accumulation of free proline, but not enough to maintainthe osmotic adaptation of the cytoplasm. Proline accumulationcould not account for the greater tolerance of the Alaska cultivar.Both cultivars contain large amounts of glutamic acid and homoserine.The amino acid composition of protein of the Alaska cultivaris affected much more by salinity than is that of Laxton Progress.In Alaska salinity induces an increase in aspartic and glutamicacids, threonine, serine, leucine and isoleucine. The totalcontent of basic amino acids decreases with salinity. The proteinof Laxton Progress is very rich in leucine and its amount slightlydecreases with salinity. In the most tolerant cultivar, Dan,there is more proline in the protein than in the other two cultivarsand its content of leucine increases with salinity. The onlyfeatures which show some correlation with salinity toleranceare proline content (Dan > Alaska > Laxton Progress) andan increase in leucine content in the protein, with increasingsalinity. Pisum sativum L, pea, amino acid composition of roots, salinity     

Effect of {alpha}-Naphthalene Acetic Acid on Variations in Free Amino Acid Contents in Developing Fruits of Capsicum annuum L.

Capsicum annuum seeds were pretreated with three concentrationsof -naphthaleneacetic acid (NAA). The fruits of the controland treated plants showed differences in the quantities of freeamino acids during three developmental stages. From a relativelyhigh amount of total free amino acids in the early phase offruit development, there was lowering in the mid-phase and furtherlowering in the terminal phase. There were eight prominent ninhydrin-reactingspots which were identified as tryptophan, glycine, glutamicacid, valine-methionine, -aminobutyric acid, leucine(s), alanine,and aspartic acid and eleven trace spots attributable to tyrosine,serine, lysine, asparagine, cystine, thrconine histidine, phenylalanine,arginine, glutamine, and ornithine. Hormone treatment tendedto decrease the total amino acids in the early- and mid-phasesof fruit development compared with the control fruits. Asparticacid was present in greater quantities in the treatments thanin the controls. In the terminal phase, the treated fruit didnot show any significant change in the total free amino acidcontents. The significance of the NAA-included variation infree amino acids is discussed. Capsicum annuum, amino acids, -naphthaleneacetic acid     

Alterations of Free Amide and Amino Acid Contents During the Development of Maize Plants, Zea mays L.

Concentrations of free amino acids and amides were measuredin organs of maize plants, Zea mays L. in the period from 14d before pollen liberation until complete seed maturation. Inthis time anthesis took place and only the ovaries of ear 9(numbered from below) developed into seeds. In mature leaf bladesNH₄ ion assimilation had ceased and asparagine and glutaminewere not found there. N redistribution induced the occurrenceof large amounts of aspartate, glutamate and alanine. The amountsof amides in leaf sheaths and stem parts depended on the neighbourhoodof generative parts. The generative plant parts can be distinguishedfrom adjacent vegetative plant parts in concentrations of freeproline or asparagine. Proline occurred in pollen but not inthe empty anthers. Ears had a small, early peak amount of prolinemostly before pollination. Only the ninth ear had a first maximumproline amount after the fifth day of pollen liberation. A secondproline peak in the ears coincided with the period of maximumincrease in d. wt. The occurrence of proline in the generativeorgans relative to metabolic processes inducing fertility orseed maturation is discussed. Zea mays L., amides, amino acids, amino-transferring components, asparagine, glutamine, proline     

Regulation of Growth and Gametangial Formation in Riccia gangetica Ahmad by Some Amino Acids

The present work deals with the effect of six amino acids: asparagine,aspartic acid, glutamic acid, glycine, serine, and tryptophan,on growth and gametangial formation in Riccia gangetica. Allthe amino acids tested enhance vegetative growth, and amongthese glutamic acid proves best. The total number of rhizoidsis reduced in response to amino acids. Aspartic acid and glutamicacid favour antheridial production. In contrast, asparagine,serine, and tryptophan enhance archegonial formation, and amongthese asparagine elicits the best response. Glycine proves bestfor antheridial production, and also increases the number ofarchegonia. Key words: Riccia gangetica, Amino acids, Growth, Gametangial formation     

Variations in the content of free and bound amino acids during dormancy and the first cell cycle in Helianthus tuberosus tuber explants

Abstract

Qualitative and quantitative analysis of free and bound amino acids and amides during dormancy and the most important phases of the first cell cycle was carried out in tubers of Helianthus tuberosus.

In the dormant tuber arginine was confirmed to be the most abundant amino acid. A high amount of asparagine was also present; on the contrary glutamine was found in very low concentrations. During the progression of dormancy, all the free amino acids and amides declined while aspartic and glutamic acid increased.

During the G₁ phase of the first cell cycle induced by 2,4-D, all the free amino acids and amides decreased with the exception of glutamic acid.

At 18, 20, 24 h of activation with 2,4-D, corresponding to the S phase and the beginning of mitosis, bound amino acids were also determined. In these phases of the cell cycle they increased reaching a maximum at 20 h; on the other hand the free amino acid and amide content, especially aspartic acid, asparagine and arginine, decreased with the exception of glutamic acid, alanine and phenylalanine.     

Comparison of Free and Bound Amino Acids in White and Green Tissues of Variegated Tobacco Plants

Qualitative and quantitative comparisons of free and bound aminoacids and soluble proteins in white and green tissues of variegatedtobacco leaves were made. White tissue contained more free andless bound amino acids than green tissue, although the sum ofthe total amino acids did not differ significantly between thetwo tissues. The major free amino acids in white tissue wereglutamine and asparagine, whereas those in green tissue wereglutamic acid, aspartic acid and -aminobutyric acid. The contentsof fraction 1 protein and 70 S ribosomes in white tissue werenegligible in comparison with those found in green tissue, butthe amounts of other soluble protein components and the 80 Sribosomes were at the same level in both tissues. (Received October 21, 1981; Accepted January 28, 1982)     

Seasonal Changes in Nitrogen Fractions of Coptis japonica, a Temperate Forest Evergreen Chamaephyte, and their Ecological Implications

Seasonal changes in several forms of nitrogen were investigatedin Coptis japonica, an evergreen rosette hemicryptophyte intemperate deciduous forest. The concentration of total nitrogenin rhizomes and roots decreased during the period of new shootgrowth from winter to spring. In the rhizomes, total solubleprotein stored by early summer decreased gradually until winter,coupled with an increase in free amino acids. Nitrogen was largelystored in free amino acids in the roots, especially during summer.The total soluble protein in current-year leaves decreased fromspring to summer and then increased during winter. The seasonalchanges in nitrogen components were coincident with the changein light-saturated photosynthetic rates recorded in a previousstudy. The ratio of total soluble protein to total nitrogendecreased from spring to summer and then increased from latesummer to winter in the current-year leaves. In contrast, chlorophyllcontent and the ratio of chlorophyll to total nitrogen werehigher in summer than in other seasons. The results indicatethat nitrogen was used in a manner that better utilizes thevery weak light in summer and the higher light intensities inother seasons. The major component of the free amino acid poolwas asparagine, in every organ throughout the season, exceptfor the senescent leaves. Since asparagine has a high N:C ratio,we suppose that the asparagine-dominated amino acid pool isadvantageous in the carbon-limited environment of the forestfloor.Copyright 1994, 1999 Academic Press Free amino acid composition, total nitrogen, total soluble protein, photosynthesis, evergreen hemicryptophyte     

Origin of Foliar Nitrogen and Changes in Free Amino-Acid Composition and Content of Leaves, Stubble, and Roots of Perennial Ryegrass During Re-growth after Defoliation

Nitrogen re-mobilization and changes in free amino acids werestudied as a function of time in leaves, stubble, and rootsduring ryegrass (Lolium perenne L.) re-growth. Experiments with¹⁵N labelling clearly showed that during the first days nearlyall the nitrogen in new leaves came from organic nitrogen re-mobilizedfrom roots and stubble. On the days of defoliation, stubblehad the highest content of free amino acids with 23 mg per gdry weight against 15 mg and 14 mg in leaves and roots, respectively.The major amino acids in leaves were asparagine (23% of totalcontent in free amino acids), aminobutyrate, serine, glutamine,and glutamate (between 7% and 15%) whereas in roots and stubblethe contribution of amides was high, especially asparagine (about50%). Re-growth after cutting was associated with a rapid increaseof the free amino acid content in leaves, with a progressivedecrease in roots while stubble content remained virtually unchanged.In leaves, asparagine increased from the first day of re-growth,while the aspartate level remained unchanged and glutamine increasedstrongly on the first day but decreased steadily during thenext few days of re-growth. Asparagine in stubble and rootschanged in opposite directions: in stubble it tended to increasewhereas in roots it clearly decreased. In contrast, stubbleand roots showed a similar decrease in glutamine. In these twoplant parts, as in leaves, aspartate remained at a low level.Results concerning free amino acids are discussed with referenceto nitrogen re-mobilization from source organs (stubble androots) to the sink organ (regrowing leaves). Key words: Lolium perenne L, re-growth, nitrogen, free amino acids, glutamine, asparagine     

Changes in accumulation of seed nitrogen compounds in maize under conditions of sulphur deficiency

Maize ( Zea mays L., hybrid INRA 260) was grown in the greenhouse with mineral nutrition of different sulphate concentrations. Mature seeds from these plants were compared for their free amino acid and protein N forms. For the most S-deficient sample, the Asx (asparagine + aspartic acid) content increased by 30% as compared with control, while methionine and cysteine decreased (by 25 and 30%, respectively), as well as glycine, lysine, histidine, arginine and tryptophan. In seeds lowest in S the non-protein N to total N ratio was 77% higher than in the control. Free asparagine dominated in starved seeds (50 mol % of total free amino acids) and was ten-fold more concentrated than in the control, where proline was the predominant free amino acid. Thus the Asx of non-protein N reached 28% of the total mol Asx of the whole starved seed. Altered S nutrition had virtually no effect on the amino acid composition of the main protein fractions, but it significantly changed their ratios. Zeins, which are poor in S-containing amino acids, showed 25% higher level than in seeds supplied with normal S. As a counterbalance, two glutelin subfractions rich in S-containing amino acids, decreased by 36–71% under limiting S nutrition.
It is concluded that the plant reacts against S deficiency by modifying its N metabolism. Significant accumulation occurred of free asparagine, which is the main form of N transportation. The biosynthesis of seed storage protein occurred through the accumulation of the highest possible protein quantity allowed by the available S-containing amino acids, i.e. proteins low in S-containing amino acids were preferentially synthesized.     

Nitrogen Metabolism of Vicia faba

Vicia faba plants were grown for four and six weeks without externally supplied nitrogen. Some nitrogen was transported to the plant axis from the cotyledons throughout this period, but the amount available was insufficient to support maximum shoot growth. During this period the protein content of the shoot declined whilst the free amino acids, especially aspartic acid, glutamic acid, histamine and the combined pool for threonine, serine, asparagine and glutamine and ammonia, increased in amount. In contrast to the shoot the protein content of the root increased as did their free amino acid content, but the increase in the latter was less than in the shoot and only the combined value for threonine, serine, asparagines and glutamine increased significantly. During tbe last two weeks growth, some soluble non-amino acid compound appeared to donate nitrogen to the pool of free amino acids in the root and shoot.     

Protein and free amino acids in wheat grain as affected by soil types and salinity levels in irrigation water

Summary The effects of four lysimeter soil series under three salinity levels were evaluated for grain yield, wt/1000 seeds, protein, and amino acids in Mexican dwarf wheat (Triticum aestivum L. var. Cajeme 71). The soil series consisted of: Holtville clay loam, Greenfield sandy loam, San Emigdio sandy loam, and Altamont clay loam. The irrigation water salinity levels were designated: low –2.2 mmho, medium –4.2 mmho, and high –7.1 mmho.No significant differences were found in the amount of grain harvested or wt/1000 seeds in the 1976 crop produced on the differential soil series. The yield of the 1977 crop was significantly affected by the soil types.Effects of soil type on the protein amino acids in the grain in both years were similar. Significantly higher protein amino acid levels of histidine, arginine, aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cystine, valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine were found in the grain grown on Altamont clay loam soil than the other types.The free amino acids in grain from the 1976 and 1977 crops were similarly affected by the soil types, except that the quantitative values of the free amino acids were substantially lower in 1977 than in 1976. The free amino acids significantly influenced by soil types were tryptophane, lysine, arginine, aspartic acid, threonine, serine, glycine, alanine, valine, isoleucine, tyrosine, and phenylalanine. In both years' crops, the sum of the free amino acid fractions was significantly higher in the grain produced on the Altamont soil than on the other soils.Salinity level in the irrigation water did not affect the 1976 crop yield or wt/1000 seeds. Although yields of the 1977 crop were significantly reduced by salinity, the wt/1000 seeds was not. The sum of protein amino acids was significantly higher in the 1976 and 1977 grain crops irrigated with high salinity water than in low salinity irrigated crops.An increased salinity irrigation water significantly reduced the sum of free amino acid fractions in the 1976 grain crop. Since some of the free amino acids in the 1977 grain crop increased while the others decreased due to the salinity level in the irrigation water, the sum of the free amino acid fractions was not significantly influenced.Significant interactions were found between soil types and salinity levels on free arginine, threonine, serine, glutamic acid, and alanine, and also on the sum of the free amino acids in the 1976 wheat grain. In the 1977 wheat grain, there were significant interactions between soil types and salinity levels on the free glutamic acid, valine, leucine, tyrosine, and phenylalanine, and on protein serine, glutamic acid, glycine, alanine, and the sum of the protein amino acids.The amounts of essential amino acids expressed as mg of amino acid/g of protein were not affected by the soil types or salinity levels. With the exception of lysine, and possibly threonine and methionine plus cystine, the essential amino acids were present in the grain at concentrations equal to or greater than recommended by WHO and FAO.     

Changes in Free Amino Acids in White and Green Tissues of Variegated Tobacco Leaves during Water Stress

Variegated tobacco leaves, white on one side of the midrib andgreen on the other, were detached from the stem and incubatedunder water stress or turgid conditions for 4 days to determineany changes in the levels of free amino acids. Drastic changes in the free amino acid composition occurredin the green tissue during the water stress period, but onlyvery small changes in the white tissue. During that time, themost striking difference between the two tissues was the largeamount of proline accumulated in the green tissue, but not inthe white. An exogenous supply of sucrose increased the prolinecontent in both tissues during water stress. An exogenous supplyof glutamic acid increased the proline and asparagine contentsin the green tissue, but it increased only the asparagine contentin the white tissue during water stress. (Received May 4, 1982; Accepted August 12, 1982)     

Amino Acid composition of germinating cotton seeds

Total and free amino acid composition of germinating cotton seeds (Gossypium hirsutum L.) was determined. The germinating seeds were separated into cotyledon and developing axis fractions daily and the composition of each tissue was summed to get the whole seed composition. By separating the developing seeds into these two tissue fractions, and determining total and free amino acids, a balance sheet was developed for each amino acid. This technique allowed changes in distribution with time of each amino acid to be followed in each tissue. Data for total content and amount in protein of each amino acid are presented. Asparagine increased in the whole seed, and most of this increase was found in the free pool of the developing axis. Other amino acids (e.g. arginine, glutamic acid) increased in the free pool but showed an over-all decrease, indicating that they were being metabolized. Amino acid contents of storage and nonstorage protein isolates were determined.     

CHANGES OF AMINO ACID COMPOSITION OF CHLORELLA CELLS DURING THEIR LIFE CYCLE

The cells of Chlorella ellipsoidea were grown synchronously,and at different stages of their life cycle, the cells wereanalysed for their contents in amino acids existing in freeforms as well as in the fractions of bulk protein and peptides.Throughout the algal life cycle, the content of bulk protein(per unit dry weight of cells) remained relatively constant,being about 20 to 40 times those of peptides and free aminoacids. The amino acid composition of the protein fraction alsoremained fairly constant, the predominant amino acids beingalanine, glutamic acid, glycine and leucine. The contents inthe bulk peptides increased appreciably during the periods ofgrowth and "ripening" (light period), and decreased markedlyduring the periods of "post-ripening" and cellular division(dark period). Similar modes of change in content were alsoobserved in most of the individual amino acids contained inthe peptide fraction. The most abundant component in the peptidefraction was arginine followed by glutamic acid, glycine andcyst(e)ine. Rather irregular was the mode of change of the levelsof individual free amino acids, although, as a whole, theirbehavior was similar to that of bulk peptides, increasing duringthe light period and decreasing during the dark period. Themost predominant free amino acids were glutamic acid and alaninefollowed by proline. Experimental evidence showed that the processes of formationof free amino acids and peptides are for the most part lightdependent, while the synthesis of protein, which is thoughtto be effected using as building blocks mostly free amino acids—formeddirectly or indirectly from early photosynthates or derivedfrom pre-formed peptides—is essentially a light-independentprocess. Peptides, as a whole, seem to have significance asreservoirs of building blocks for the syntheses in the darkof protein and other nitrogenous cellular substances. The synthesisof protein in the dark takes place not only by consuming thefree amino acids and peptides that have been accumulated duringthe light period, but also by assimilating the exogenous nitrogensource (nitrate). The distribution of individual amino acidsin the three main fractions mentioned above as it changed duringthe course of algal cell cycle was followed in detail, and theresults obtained were discussed in relation to various relevantdata reported by other workers. (Received June 29, 1964; )     

Salinity Stress and the Content of Proline in Roots of Pisum sativum and Tamarix tetragyna

Amino acid composition of the free amino acid pool and the TCA-insolubleprotein fraction were investigated in root tips of pea and Tamarixtetragyna plants grown at various levels of NaCl salinity. Salinitystress induced an increase of proline content, mainly in thefree amino acid pool in both plants, and of proline or hydroxyprolinecontent in the protein. Externally-supplied proline was absorbedand incorporated into protein, by pea roots, more effectivelythan by Tamarix roots. Salinity stress, apparently, stimulatedthe metabolism of externally-supplied labelled proline. Pearoots have a very large pool of free glutamic acid; however,70 per cent of the ¹⁴C from externally-supplied ¹⁴C-U-glutamicacid was released as CO₂. Very small amounts of it were incorporatedinto protein. No measurable amount of radioactivity could bedetected in any one of the individual amino acids, either ofprotein hydrolysate or the free amino acid pool. Proline very effectively counteracted the inhibitory effectof NaCl on pea seed germination and root growth. A similar effectbut to a lesser degree was achieved with phenylalanine and asparticacid. The feasibility of proline being a cytoplasmic osmoticumis discussed.     

FREE AMINO ACIDS IN DEVELOPING RAT RETINA

—During postnatal growth the free amino acids pattern of rat retina differs at various developmental stages. The adult level for individual amino acids is reached on the 30th day of maturation. During differentiation the taurine, glutamic acid, GABA, glutamine, aspartic acid, glycine arginine, methionine and histidine levels increase while proline. alanine, ornithine and tyrosine decrease.     

Internal Zinc Accumulation Is Correlated with Increased Growth in Rice Suspension Culture

A high zinc concentration of 520 μm, approximately 100 times that used most often in standard plant tissue culture media, was found to be superior in liquid callus cultures of japonica rice, increasing growth to 146% compared with standard N6 medium. At the same time, the internal zinc concentration increased 40 times in fast growing cells; soluble protein doubled, and free amino acids decreased. Under zinc-free conditions the cultures slowed in growth, and several free amino acids such as aspartic acid, glutamic acid, asparagine, and glutamine accumulated. We suggest that zinc acts as a direct regulatory factor in inducing auxin activity, but not auxin levels, making high internal zinc accumulation mandatory if high auxin concentrations are required as in rice callus cultures. Received July 16, 1997; accepted September 22, 1997     

Amino acid composition of autotrophic and heterotrophic cultures of the Emerson strain, of Chlorella

"Giant" cells of the Emerson strain of Chlorella are deficientin certain peptide amino acids as compared with normally growingcells. "Giant" cell peptides lack aspartic acid, glutamic acidand alanine (major peptide amino acids in dividing cells) althoughall three are present in "giant" cells as free amino acids andin the protein fraction. (Received October 18, 1975; )     

Free amino acid contents of the gametophytic blades from the green mutant conchocelis and the heterozygous conchocelis in Porphyra yezoensis Ueda (Bangiales, Rhodophyta)

Free amino acid contents in green mutant(G-1) blades and sectored F₁gametophytic blades with green andwild-type portions, which were developedfrom heterozygous conchocelis obtained by across between the wild type (0110) and thegreen mutant (G-1) of Porphyrayezoensis, were compared with those of thewild-type blades in laboratory culture. The contents of the major four free aminoacids (aspartic acid, glutamic acid,alanine and taurine) as well as those ofthe total free amino acids were highest inthe green mutant blades, intermediate inthe F₁ gametophytic blades, and lowestin the wild-type blades. A similar trendwas obtained in the blades developed frommonospores of the F₁ gametophyticblades. In addition, the green-typesectors also had a higher content of thefour major free amino acids and total freeamino acids compared with the wild-typesectors in the F₁ blades cultivated ata nori farm. The green mutant ischaracterized by higher contents of thefour major free amino acids compared withthe wild type, which has a higher growthrate. Hence, it is considered that thesectored F₁ gametophytic bladesproduced from the heterozygous conchocelishave both parental advantages (high freeamino acid contents and high growth rate)and compensate for both parentaldisadvantages. This seems to be one of thepossible ways of genetic improvement inregards to the taste of nori and stableproduction in Porphyra cultivation.