Effet du phosphate et du calcium sur la croissance et l'accumulation ionique chez les champignons ectomycorhiziens en culture in vitro

1984 ◽  
Vol 62 (12) ◽  
pp. 2600-2609 ◽  
Author(s):  
Daniel Mousain ◽  
Louis Salsac

The orthophosphate and calcium influence on growth and ionic accumulation was studied in several ectomycorrhizal fungi (Pisolithus tinctorius included) grown in vitro. The "optimal" growth was obtained with [Formula: see text] concentrations much lower than those of usual media: it may be represented by an exponential function, the parameters ("maximal" growth and "concentration of half-maximal growth") of which were calculated. For low phosphate and calcium concentrations in the medium the dry matter mass of the mycelium and their content of the two elements increased simultaneously. For high concentrations, an accumulation independant of growth was observed in the thalli. When the P. tinctorius mycelium accumulated phosphate and calcium in relatively large amounts, these accumulations seemed to be not correlated. Rather, the correlation between the accumulation of total phosphorus and that of potassium was significant. The ratio of acid-soluble P to total P decreased in the mycelium when the orthophosphate concentration increased in the medium.

2016 ◽  
Vol 40 (3) ◽  
pp. 203 ◽  
Author(s):  
Bambang Suwignyo ◽  
Bela Putra ◽  
Nafiatul Umami ◽  
Cahyo Wulandari ◽  
Ristianto Utomo

This study aimed to determine the effect of arbuscular mycorrhizal fungi (AMF) and phosphate (P) fertilizer on the nutrient content, phosphate uptake and in vitro digestibility of alfalfa (Medicago sativa L.).The research was conducted at green house of Forage and Pastures Science Laboratory, Faculty of Animal Science Universitas Gadjah Mada. The experiment was arranged in Completely Randomized Design using 3x4 factorial patterns with four replications. The first factor was dosage of phosphate fertilizer SP 36 (0, 60, and 120 kg/ha). Second factor was the dosage of AMF (0, 0.8, 1.6, and 2.4kg/ha). The variable measured was nutrient contents (crude protein, dry matter, and organic matter), total P uptake and dry matter and organic matter in vitro digestibility. The results showed that the interaction of AMF and P fertilizer had no significant effect on crude protein and total P uptake, but highly significant effect on the parameters of dry matter, organic matter and dry matter and organic matter in vitro digestibility. 


1972 ◽  
Vol 23 (6) ◽  
pp. 959 ◽  
Author(s):  
JB Hacker ◽  
DJ Minson

Six Setaria introductions were grown in small plots at three sites differing in soil type and location in south-eastern Queensland, and fertilizer and irrigation water were applied at similar rates. All plots of each introduction were genetically identical. Three different cutting regimes were imposed, such that at 12-week intervals during the 2 years of the experiment 4, 8, and 12-week regrowth was available for comparison of in vitro dry matter digestibility. There was an overall difference in digestibility between varieties of 6.6 percentage units, and the ranking order was usually the same for all sites, seasons, and ages of regrowth. Three of the introductions were consistently superior to cv. Nandi, the only commercial cultivar included in the present study. The two Setaria splendida introductions ranked second and sixth, although they were both higher in ash concentration than the other introductions, and this was associated with high potassium content. Differences between varieties in digestibility were not associated with flowering differences, despite large differences in flowering behaviour. The maximum mean difference between sites was 4.9 units and this was associated with differences in ash content. Difference in ash content, however, accounted for only 23% of the digestibility difference. The high ash content was associated with high concentrations of potassium. There was no association between nitrogen content and digestibility. The introduction lowest in digestibility had the highest nitrogen content. Digestibility was higher in winter than in summer at all sites, and the extent of this difference increased with age of regrowth. Higher digestibilities were obtained in younger regrowth.


1988 ◽  
Vol 68 (3) ◽  
pp. 751-760 ◽  
Author(s):  
J. CHIQUETTE ◽  
K.-J. CHENG ◽  
J. W. COSTERTON ◽  
L. P. MILLIGAN

Two new isosynthetic strains of birdsfoot trefoil (Lotus corniculatus L.), containing low or high concentrations of tannin, were tested using in vitro and in sacco digestibility techniques. The high tannin (HT) strain contained an average of five times more tannin on a dry matter basis, than the low tannin (LT) strain. After 24-h in vitro digestion, by a rumen inoculum, there was less (P < 0.01) dry matter disappearance (45.7 vs. 54.4%) from the HT strain. Also, the development of gas pressure was lower (P < 0.01) and production of volatile fatty acids less (P < 0.05) with the HT strain than with the LT strain. Average dry matter loss from four replicated nylon bags was also lower (P < 0.01) for the HT strain than for the LT strain after 8, 12, and 24 h of incubation in rumen. These data indicate that a LT strain of birdsfoot trefoil might improve the forage digestibility. Key words: Birdsfoot trefoil, tannin, digestibility


1989 ◽  
Vol 1 (2) ◽  
pp. 120-123 ◽  
Author(s):  
Kristie L. Willett ◽  
Steven C. Loerch ◽  
Lynn B. Willett

Halogenated hydrocarbons such as polychlorinated biphenyls (PCB's), heptachlor (HEP), 1, 1, 1,-trichloro-2, 2-bis(p-chlorophenyl)-ethane (DDT), and pentachlorophenol (PCP) are environmental contaminants and, at times, can bioaccumulate in the food chain. Cattle have been contaminated in a variety of ways, but generally it is believed that they are only affected by high concentrations of the chemicals. Rumen microorganisms, however, may be affected at lower doses, thus possibly affecting the cow's growth and milk production. Polychlorinated biphenyls, HEP, DDT, and PCP were tested by a l-stage in vitro fermentation procedure. Substrate utilization was determined by measuring percent dry matter disappearance. Four concentrations (0, 10, 50, and 100 ppm) were studied, and in vitro incubations were conducted for 24 and 48 hr. Samples were removed from 48-hr incubations to determine if the chlorinated hydrocarbons were metabolized during fermentation. Dry matter disappearance proved to be a reliable method to determine microbial activity in the presence of chemicals. Substrate dry matter disappearance for controls and all concentrations of PCB's, HEP, and DDT was approximately 50 and 80% at 24 and 48 hr, respectively. The PCP significantly (P < 0.05) depressed the percent dry matter disappearance in 50- and 100-ppm cultures to 45 and 30% at 24 hr and 70 and 50% at 48 hr, respectively. Metabolic changes in the test chemicals were not detected by gas chromatographic analysis.


2000 ◽  
Vol 30 (8) ◽  
pp. 1221-1230 ◽  
Author(s):  
Karoliina Niemi ◽  
Maija Salonen ◽  
Arild Ernstsen ◽  
Helvi Heinonen-Tanski ◽  
Hely Häggman

The ectomycorrhizal fungi, Pisolithus tinctorius (Pers.) Coker & Couch and three Paxillus involutus (Batsch) Fr. strains, were used to enhance in vivo rooting in fascicular shoots of 49 Scots pine (Pinus sylvestris L.) genotypes representing seed families from southern and northern Finland. Inoculation with specific fungi either increased the rooting percentage or accelerated root formation expressed as an increased number of adventitious roots per cutting. Only one of the six seed families gave no positive response. The relationship between the in vitro production of free and conjugated forms of indole-3-acetic acid (IAA) by the fungi and rooting was also investigated. Pisolithus tinctorius was the only significant producer of IAA in the absence of exogenous tryptophan. All the Paxillus involutus strains also synthesized both free and conjugated IAA but did that actively only from exogenous tryptophan. In vitro production of IAA did not correlate with root induction in vivo, but the rooting responses depended on the fungus strains and the Scots pine seed families and (or) genotypes within families. This indicates that in vitro IAA production capacity cannot be the only criterion when selecting ectomycorrhizal fungi for rooting in vivo and that specific genotype-genotype interactions play a key role in root initiation.


2020 ◽  
Vol 98 (10) ◽  
Author(s):  
Lucas M Horton ◽  
Cadra L Van Bibber-Krueger ◽  
Hans C Müller ◽  
James S Drouillard

Abstract Developed initially for use in fuel ethanol production, Enogen Feed Corn (EFC; Syngenta Crop Protection) is genetically modified to express high concentrations of α-amylase in the corn kernel. Experiments were conducted to evaluate processing characteristics of EFC, in vitro digestion, and effects on feedlot performance, carcass characteristics, and liver abscess incidence. Experiment 1 used a randomized complete block design (3 × 3 × 5 factorial) to evaluate starch availability, in situ dry matter disappearance (ISDMD), in vitro gas production (IVGP), and volatile fatty acid (VFA) profiles of in vitro cultures. Grains (EFC or mill-run control [CON]) were flaked to a density of 360 g/L, and mixtures with 0%, 25%, 50%, 75%, or 100% EFC were prepared. Grains were tempered with added moisture (0%, 3%, or 6%) prior to steam conditioning for 15, 30, or 45 min. No two- or three-way interactions were observed. Adding moisture improved starch availability (linear; P &lt; 0.01), and tended to improve ISDMD (linear, P = 0.06). Steam conditioning for 30 min improved starch availability, IVGP, and production of acetate, propionate, butyrate, valerate, and total VFA (P &lt; 0.01) compared with conditioning for 15 or 45 min. Starch availability, ISDMD, IVGP, acetate, propionate, valerate, and total VFA production increased with an increasing proportion of EFC (linear, P &lt; 0.01). Experiment 2 used 700 beef heifers (394 ± 8.5 kg initial body weight [BW]) fed finishing diets with steam-flaked corn as CON or EFC for 136 d. Targeting similar starch availabilities, grains were processed to 360 g/L (CON) and 390 g/L for CON and EFC, respectively. Heifers were blocked by BW, stratified, and then randomly assigned to 28 dirt-surfaced pens (25 animals per pen). Dry matter intakes were similar between treatments (P = 0.78), but cattle fed EFC had greater average daily gain (P &lt; 0.01), improving feed efficiency by 5% (P &lt; 0.01). Hot carcass weight was 6 kg greater for EFC cattle (P &lt;0.01) than CON. No differences were observed for longissimus muscle area (P = 0.89), 12th-rib fat thickness (P = 0.21), or USDA yield grade (P = 0.13). Cattle fed CON had greater marbling scores than EFC (P = 0.04), but this did not affect the USDA quality grade (P &gt; 0.33). Cattle fed EFC had 23% fewer abscessed livers than CON (P = 0.03). High-amylase corn may be used to improve microbial digestion, mill-throughput, and cattle performance, and it may mitigate liver abscesses.


2001 ◽  
Vol 31 (4) ◽  
pp. 703-710 ◽  
Author(s):  
Jonathan R Cumming ◽  
Troy D Swiger ◽  
Betsy S Kurnik ◽  
Daniel G Panaccione

Ectomycorrhizal fungi exhibit varying degrees of aluminum (Al) tolerance and often confer Al tolerance to their host trees. The mechanisms of Al tolerance operating in ectomycorrhizae have yet to be elucidated. We exposed cultures of Laccaria bicolor (Maire) P.D. Orton and Pisolithus tinctorius Coker & Couch to Al in vitro and assessed organic acid production and the accumulation of Al and other nutrients in mycelia. Both L. bicolor and P. tinctorius were tolerant of Al in culture media at concentrations up to 500 µM. Aluminum did not significantly alter patterns of organic acid exudation in L. bicolor. Exposure to Al changed organic acid exudation profiles of P. tinctorius, altering patterns of tartrate, glycolate, and formate production and inducing oxalate production. Although growth was unaffected by Al in media, the concentrations of Ca, Mg, and Fe in mycelia were significantly reduced by exposure to Al in both species. The concentration of Al in mycelia increased with media Al concentration, with P. tinctorius accumulating four times more Al than L. bicolor. These results suggest that organic acid production may not be involved in Al tolerance in these ectomycorrhizal fungi, since patterns of exudation were not affected by Al in L. bicolor and the production of oxalate by P. tinctorius was ineffective at ameliorating Al-induced changes in ion accumulation by mycelia of this species.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.


1970 ◽  
Vol 23 (03) ◽  
pp. 601-620 ◽  
Author(s):  
Th. B Tschopp

SummaryAggregation of cat platelets in the citrated plasma is examined by means of Born’s absorptiometer. A marked tendency of the platelets of this species to spontaneous aggregation necessitated first of all the development of an improved technique of blood collection.A hypothesis according to which 5-HT is released from the platelets, explains the absence of oscillations on the base line of the absorptiometer, the absence of platelet swelling, when ADP is added, and the effect of stirring on the aggregation curves in cat PRP. The average volume of cat platelets amounts to 10.46 μ3 when directly fixed in the blood, when fixed from PRP to 12.17 μ3, when fixed from stirred PRP to 13.51 μ3.In low concentrations (0.3-2 μM) ADP produce reversible aggregation; in narrowly restricted, individually dissimilar mean concentrations irreversible aggregation in two phases and in high concentrations, irreversible aggregation in one phase. Like ADP serotonin produces 2 phase irreversible aggregation in concentrations of 3-10 μM, but unlike ADP, the aggregation velocity decreases again with high 5-HT concentrations (>100 μM). Adrenaline does not produce aggregation and it is likely that adenosine and adenosine monophosphate inhibit the aggregation by serotonin but not by ADP. Species differences in the aggregation of human, rabbit and cat platelets are discussed.


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