Percentage Of Total Carbohydrates Research Articles

Growth and Photosynthate Partitioning in Alfalfa Under Eight Temperature‐Photosynthetic Period Combinations1

AbstractA characterization of the growth responses of high and low yielding alfalfa (Medicago sativa L.) plants to environmental parameters will provide important information on their yield potential. This experiment was conducted to determine if growth temperature and length of the photosynthetic period mediate the differential herbage yielding abilities of alfalfa genotypes previously selected under field conditions for high and low herbage yield. Twelve genotypes were grown at 20/15, 23/18, 26/21, and 29/24 C day/night temperatures in 10‐hour and 14‐hour photosynthetic periods in controlled environments. Dry weights and total nonstructural carbohydrate percentages were obtained on herbage and root tissues. Carbon dioxide exchange rates were measured using infrared gas analysis on attached leaves and expressed on a per unit leaf area and a per unit leaf dry weight basis. Relatively large herbage yield differences previously observed among the various clones under field conditions were minimized in all treatments when plants were grown in controlled environments where moisture and nutrient stresses were assumed to be minimal. The apparent diurnal accumulation rate of total nonstructural carbohydrates was faster in the herbage of plants grown in short photosynthetic period conditions than in those grown in long ones. Such a relationship suggests an influence on photosynthate partitioning by length of the daily photosynthetic period. We conclude that yield differences observed under field conditions were not necessarily related to differential responses to either temperature or length of the daily photosynthetic period. Furthermore, photosynthesis, as measured by single leaf CO2 exchange rate, was not positively correlated with herbage yield under the various controlled environmental conditions used in this experiment.

Aspects qualitatifs de la digestion intestinale des glucides d'un tourteau de soja par le veau préruminant

Two 15-day old preruminant calves, fitted with reentrant ileocaecal and single colon cannulae, were fed a milk substitute containing 47 p. 100 of toasted soya oil meal, 17 p. 100 of crystallized tallow, 28.5 p. 100 of lactose, 7.0 p. 100 of minerals plus vitamins and 0.5 p. 100 of DL-methionine all on a dry basis. Samples from the ileum, colon and faeces were collected every 2 hrs for 8 hrs after feeding, when the calves 1 and 2 were 4 and 9 week-old, respectively. Total water-soluble carbohydrates were determined, then identified by ion-exchange chromatography. In this preliminary work, we only present results on the healthiest calf. At the end of the small intestine, sucrose and alpha-galactosides were probably poorly digested. Their concentration (as a percentage of total water-soluble carbohydrates) was the same as in the soya bean. In the large intestine, these carbohydrates were completely utilized and the sucrose was break down faster than the alpha-galactosides. The end product of fermentation was mainly lactic acid (4-8 g/l of intestinal contents), and the pH values of the large intestine contents were low (4.0-4.9), but these fermentations did not cause digestive problems, such as diarrhea, probably because the amount of soya carbohydrates in the food was low, and the digestive processes along the digestive tract were very regular.

Distribution of chemical constituents among shoot parts of timothy and switchgrass at anthesis

Abstract Switchgrass (Panicum virgatum L.) and timothy (Phleum pratense L.) shoots were harvested at 12 noon during three days at Madison, Wisconsin. Shoots were separated into the inflorescence, individual green leaf blades, green leaf sheaths, and internodes. Switchgrass shoots, inflorescences, and leaves were greater in dry weight than those of timothy. Switchgrass shoots had higher concentrations of all macro‐ and microelements measured than timothy, except for K. Most shoot parts of switchgrass were low in K percentage, indicating that switchgrass possibly may have a lower critical K level than timothy for maximum herbage production. Switchgrass shoots contained a concentration of Mg that was three times higher than timothy. This difference is worthy of note since one problem associated with grazing is hypomagnesemia. Fructosans were found only in timothy, but both grasses contained starch. Percentage of total nonstructural carbohydrates (TNC) was nearly three times higher in the shoot of timothy tha...

Plant Maturity and Cutting Frequency Effect on Total Nonstructural Carbohydrate Percentages in the Stubble and Crown of Timothy and Orchardgrass1

AbstractConcentration of total nonstructural carbohydrates (TNC) in perennial bunch‐grass stubble is an indicator of its physiological condition. However, there is little information connecting management systems with stubble carbohydrate reserves. The object of this study was to evaluate the influence of initial harvest and subsequent height of regrowth at cutting on TNC levels in the stubble and crown of ‘Climax’ timothy (Phleum pratense L.) and ‘Pennlate’ orchardgrass (Dactylis glomerata L.). Firstgrowth was harvested at: transition (changing of apical meristem from vegetative to reproductive growth), boot (flower head emergence), or anthesis stage. After initial harvest, regrowth was harvested at 10. to 15‐, 20‐ to 25‐,30‐ to 36‐, 41‐ to 46‐, or 51‐ to 56‐cm plant heights.Both grasses had low TNC percentages (4 to 5%) at their transition stage. Delaying initial harvest of timothy until boot or anthesis stage increased stubble and crown TNC percentages four to five times.Delaying initial harvest of orchardgrass to boot stage had little effect on stubble and crown TNC percentages. However, stubble‐crown reserves increased 5 percentage points when initial harvest was delayed to anthesis. With frequent harvesting of both grasses, TNC percentages remained low, but the trends of TNC increased as the frequency of harvest decreased. By early November both species had a high stubble and crown TNC percent. age regardless of the regrowth harvest schedule. Stubble and crown TNC percentage was generally lower by the following spring for all treatments, with orchardgrass exhibiting the greatest decrease. These data indicate that the seasonal trend of stubble and crown TNC accumulated by each grass species reflects the harvest management system imposed during that growing season.

Naturally-Ocurring Low Molecular Weight IgM in Patients with Rheumatoid Arthritis, Systemic Lupus Erythematosus, and Macroglobulinemia

Abstract Some physicochemical properties of naturally occurring low molecular weight IgM (LMW IgM), IgM and their subunits obtained by reduction-alkylation were compared. On the basis of analytical ultracentrifugation, SDS polyacrylamide electrophoresis, analytical Sephadex chromatography, and heavy (H) and light (L) chain composition purified LMW IgM had an S20, w constant of approximately 8S, a molecular weight of 195,000 to 205,000 and a structural formula H2L2. Reduction and alkylation of IgM (IgM RA) by two techniques produces two components which could be distinguished by analytical ultracentrifugation, sucrose density ultracentrifugation, and gel filtration studies. IgM RA-cys had an estimated molecular weight similar to LMW IgM and IgM-2ME had physical properties similar to IgG. The molecular weights of H and L chains of IgM and LMW IgM were similar: 69,000 to 75,500 and 26,000 to 27,000, respectively. Unlike LMW IgM and IgM RA-cys, the less dense IgM RA reduced with 2ME dissociated into half subunits, and free H and L chains in SDS gel electrophoresis, indicating that it lacked intra-subunit disulfide bonds. J chain was not detected in LMW IgM or in the chromatographically purified reduced-alkylated subunits from a patient whose IgM contained J chain. Carbohydrate analyses of IgM, LMW IgM, and reduced-alkylated IgM products did not demonstrate differences in individual sugars or in the percentage of total carbohydrate. The different sedimentation and gel filtration properties of the two components obtained by reduction-alkylation of IgM could not be attributed to variations in peptide chain or carbohydrate content, rather they are probably dependent on conformational changes resulting from variable reduction of intra-subunit disulfide bonds.

Comparison of isolation and chemical composition of kidney glomerular basement membranes in rabbit, rat and man

1. 1. Kidney glomeruli were isolated in rabbit, rat and man by means of stainless steel sieves adapted to each species. Glomerular basement membrane (G.B.M.) were obtained by sonication of the glomeruli and extensive washings first in 1 M NaCl and then in distilled water. 2. 2. Amino acid composition of the G.B.M. is similar in the three species with important amounts of glycine, hydroxyproline and hydroxylysine and half-cystine. 3. 3. Carbohydrate analysis by gas chromatography after hydrochloric methanolysis shows in the three species an equimolar amount of glucose and galactose forming disaccharide glucosyl-galactosyl units linked to hydroxylysine and a substantial amount of sialic acids, N-acetyl-glucosamine and mannose. 4. 4. In the three species, total carbohydrate percentage was between 7 and 10 per cent and phospholipid content varied from 2 to 4 per cent.

Response of Phalaris Genotypes and Other Cool‐Season Grasses to Temperature1

AbstractImproved winter forage production is a major objective in breeding phalaris (Phalaris tuberosa L.) varieties for the southeastern United States. The purpose of our study was to determine morphological and physiological parameters accounting for winter forage productivity. Winter‐productive phalaris genotypes in field and growth chamber experiments responded rapidly to increasing temperatures with more rapid appearance of new leaves and greater leaf expansion rates than tall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.), orchardgrass (Dactylis glomerata L.), or winter‐dormant phalaris types. Tiller numbers were not related to winter productivity. Fructosans comprised a higher percentage of total nonstructural carbohydrates in winter‐productive than in less winter‐productive phalaris genotypes. Phalaris genotypes did not differ in photosynthetic rates per unit area of leaf surface at several temperatures. Winter‐productivity of certain phalaris genotypes appears to result from rapid development of new leaves and rapid leaf expansion during short periods of favorable temperature, possibly aided by a supply of readily translocated carbohydrates.

Carbohydrates of spring and winter field beans (Vicia faba L.).

AbstractThe proportions of available and unavailable carbohydrate were determined in samples of eight varieties of field beans (Vicia faba L.). Available carbohydrate consisted of dextrins, water‐soluble and insoluble starches and ethanol‐soluble sugars; the unavailable carbohydrate fraction contained lignin, cellulose, hemi‐cellulose and water‐soluble polysaccharides. The component sugars of extracts and hydrolysates of all fractions except lignin were measured by anion‐exchange, thin‐layer and paper chromatography.Winter‐sown beans contained 46 to 48% available and 19 to 20% unavailable carbohydrate, while spring‐sown beans contained 30 to 42% available and 22 to 37% unavailable carbohydrate on a dry matter basis.Two of the spring‐sown varieties were atypical in certain respects: Strubes had a high percentage of available carbohydrate (42.4%), similar to the level found in winter‐sown beans, while Ackerperle had a high percentage of total carbohydrate (67.4%) but the lowest percentage of available carbohydrate (30.1%). The protein content of Strubes (30.2%) was typical of spring‐sown varieties, but that of Ackerperle (27.7%) corresponded to the lower level of winter varieties.

The influence of aerial environment, nitrogen supply, and ontogenetical changes on the chemical composition and digestibility of Panicum maximum Jacq. var. trichoglume Eyles

The effect of aerial environment and nitrogensupply on the chemical composition and in vitvo digestibility of a tropical grass was studied by comparing plants of Panicum maximum var. tvichoglume grown in pots either outdoors or in an humidified glasshouse. Plants from the two environments were similar in their percentage content of protein and cell wall materials. Young tissue from the outdoor plants was more digestible than material from the glasshouse, but the digestibility of this material was nevertheless very high in all plants. Thus, it appears that the unusually high nitrogen percentages and digestibilities which have been recorded for tropical grasses in laboratory studies by comparison with field-grown material may not be directly associated with differences in the aerial environment. This point remains to be conclusively tested under precisely controlled conditions. Increase in nitrogen supply from low to moderate levels increased digestibility by 3-5 percentage units, and had a small positive effect on the percentage of total soluble carbohydrates. Very high nitrogen supply lowered the soluble carbohydrate content of the plant tops. There was an inverse relation between tissue nitrogen concentration and the content of cell wall material. The amount of cell wall material increased progressively from the earlier- to the later-formed leaves on a tiller. When compared at a similar age, later-formed leaves tended to be less digestible. This influence of leaf position on nutritive quality is very interesting and warrants further investigation.

Total Nonstructural Carbohydrate Concentrations in the Herbage of Several Legumes and Grasses at First Flower1

AbstractHerbage of several forage legumes and grasses was harvested at first flower (beginning of anthesis in grasses) and analyzed for percentage of total nonstructural carbohydrates (TNC) during 3 years. No significant difference was found among species for the 3‐year averages. However, red dover (Trifolium pratense L.), among the legumes, and timothy (Phleum pratense L.), among the grasses, were consistently high in TNC percentage during all 3 years.

Influences of Several Management Practices on Growth Characteristics and Available Carbohydrate Content of Smooth Bromegrass1

AbstractHerbage yields of bromegrass (Bromus inermis Leyss.) grown without alfalfa were favored by infrequent cutting (3 cuts) primarily because spring growth yields were increased. Nitrogen fertilizer (168 kg/ha) increased bromegrass yields by increasing the number of tillers and rapidity of regrowth after cutting. Herbage yields of bromegrass plants grown with alfalfa were favored by frequent cutting (5 cuts) because fewer shoot apices were removed by frequent cutting and because alfalfa was less competitive.Frequent cutting decreased slightly the percentage of total available carbohydrates (TAC) accumulated between cuttings in the stem bases of bromegrass. Nitrogen fertilizer increased depletion of TAC after cutting, but did not affect the maximum level accumulated. Association with alfalfa decreased markedly the percentage of TAC in bromegrass during the growing season. High levels of TAC were present under all the treatments when growth ceased during late autumn.

EFFECT OF COLD TREATMENT ON ALFALFA AS INFLUENCED BY HARVESTING SYSTEM AND RATE OF POTASSIUM APPLICATION

Alfalfa plants were grown in the greenhouse and harvested by three systems: (1) as one hay crop, (2) as two hay crops, and (3) as a hay crop followed by two pasture cuts. The cutting systems were arranged factorially with three levels of potassium fertilization: no potassium, 200 lb K per acre, and 300 lb K per acre. After hardening and freezing in an environmental control chamber, plants which were harvested only once had the best recovery, the most etiolated regrowth, and the highest percent of total available carbohydrates (TAG) in the roots. Plants harvested only once also had the largest root weight but the lowest yield of harvested herbage. One crop harvested at early bloom followed by two pasture cuts produced the second highest herbage yield, the lowest root yield, the lowest percentage of total available carbohydrates in roots, the highest percent K and P in the tissue, the lowest yield of etiolated regrowth, and the poorest recovery after freezing.Plants which received 200 and 300 lb K per acre were not significantly different in most criteria measured but gave higher yields than the plants which did not receive additional K. Etiolated regrowth, percent TAG in the roots, and recovery rating were better for plants fertilized with K. The plants which recovered best after the cold treatment were those fertilized with K and allowed to reach full bloom following the first hay-cut.

THE ASSOCIATION OF FLOWERING HABIT WITH WINTER SURVIVAL IN RED AND ALSIKE CLOVER DURING THE SEEDLING YEAR OF GROWTH

The percentage of plants that flowered in the seedling year in spaced populations of red and alsike clovers at Madison and Arlington, Wisconsin, was highest in the earliest seedings (May 15) and decreased with later seeding dates. No plants flowered in the July 15th seedings. The percentage of winterkilling during the first winter was higher in the flowering plants of each clover than in the non-flowering plants. Differences in flowering and winter survival were noted among clover strains and in winter survival among plant types within strains.Prevention of flowering in medium red clover by removing flower buds, flowering stems and/or elongating tillers resulted in greater vegetative vigour and winter survival. Plants that were allowed to flower freely in the seedling year in spaced populations had a smaller number of non-flowering crown tillers, a smaller width of crown, a lower dry weight of crown, root and total available carbohydrates in the roots, less root branching, a slightly lower percentage of total available carbohydrates in the roots, and more winterkilling during the first winter than plants that were prevented from flowering. These responses may help in part to explain the benefits attributed to clipping red clover in the seedling year.

STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

The effects of cutting on the root, stubble and herbage growth of perennial ryegrass during establishment was studied under sward conditions.Although a few weeks after a cutting treatment there was a smaller root weight on the cut than on the uncut swards, this difference eventually disappeared.By the autumn the frequently cut swards had considerably more plants and tillers per unit area than the uncut plots. As a result of these changes in plant density the root weight per unit area of the sward was not decreased by increasing the cutting frequency during establishment. However, the root weight per plant (and per tiller) was decreased by increases in the cutting frequency.The root and stubble weights increased during the spring, summer and early autumn of the first year and decreased during the winter. In the second season the root weight increased to a maximum in December whilst the stubble weight rose during the spring and summer and decreased after September.Although the percentage of total soluble carbohydrate was consistently higher in the stubble than the roots or herbage the quantity was similar in both roots and stubble, and in these organs the major soluble carbohydrate was fructosan.During the winter both the percentage and the total quantify of soluble carbohydrate in the stubble and roots decreased considerably.Herbage growth in February and March was not correlated with the root weight per unit area in the previous autumn but was positively correlated with the root weight per plant. The highest herbage yield in the early spring came from plots which were leniently treated in the previous autumn: these plots had a low plant and tiller density but the root weight per plant or per tiller was relatively high.In April the rate of herbage growth tended to be positively correlated with the sward density. In May and June the highest herbage yields came from the open swards. It was suggested that during this latter period moisture, and/or nitrogen, may have been the limiting factor, so that the open sward benefited from less interplant competition.

Growth Cycle Metabolism of Plants in Relation to Flowering

An examination of the percentages of total carbohydrate, nitrogen (Kjeldahl) and ash has been made at various times in the growth cycle in six plants of varying growth habit. The time of formation of the flower initial in four species (fumitory, leek, radish and yellow water‐lily) corresponds to a maximum in the curve showing percentage of total carbohydrate plus percentage of ash in the whole plant. The other two species (pea and bean) make their flower initials very early in the growth cycle, at a time when the amounts of carbohydrate plus ash are high because of the attachment of the plant to the large seed. These two species therefore also make their flower initials at a virtual maximum of carbohydrate plus ash. All six species of plants studied have mobile carbohydrate. The distribution of nutrients after flowering is discussed.

Storage of Root Reserves in Rhodes Grass

It is a well-known fact that roots of many perennial herbaceous plants function as organs of storage, even where there are no special morphological modifications of root system. Root-storage phenomena in herbaceous plants have been studied in detail by a number of workers. Graber and associates (7) found that in lucerne, polysaccharides and nitrogen increased in percentage and amount in roots during mature stages whereas spring growth was associated with a decrease in percentage of nitrogen and soluble sugars in both tops and roots. The authors conclude that is greatly accelerated during periods of blossoming and seed formation. At such periods, plant produces reserve foods in excess of amounts used in vegetative extension and a surplus is stored in roots- Willard (20), likewise working on lucerne, made similar observations. Aldous (1) found that in roots of Vemonia baldwinii, Andropogon scoparius, Symphoricarpus vulgaris, Rhus glabra and Verbena stricta percentage of nitrogen, total sugars and starch in general decreased to about time of flowering, after which considerable increases of these constituents were recorded. Aldous thinks that after time of flowering the plants begin to restore reserves which must have been drawn on to produce top growth. Similarly, Grandfield (8) reports a 23.8 per cent, increase in amount of total carbohydrates and a 16.8 per cent, increase in amount of total nitrogen in roots of Verbena stricta during period between budding and maturity, and approximately same increases in roots of Solidago rigida and Vemonia baldwinii. According to Bews and Vanderplank (5), percentage of total carbohydrates increased during entire season and that of total soluble sugars during winter only, in conns of Hypoxis rooperi, while percentages of same compounds decreased in leaves between spring and autumn. The authors think, however, that in this plant the large carbohydrate reserves are drawn upon to only a very slight extent when new leaves are produced in spring. * ' More recently data have been collected with regard to storage and utilization of root reserves in various grasses. Sturkie (16) found that rootstocks of Sorghum halepense were developed after maturing of aerial plant parts; this was confirmed by Sampson and McCarty (14) in Stipa pulchra, where an accumulation of carbohydrate reserves in roots was observed during maturation. In roots of Digitaria eriantha and Themeda