The production of toxin in annual ryegrass, Lolium rigidum, infected with a nematode, Anguina sp., and Corynebacterium rathayi

1979 ◽  
Vol 30 (1) ◽  
pp. 201 ◽  
Author(s):  
BA Stynes ◽  
DS Petterson ◽  
J Lloyd ◽  
AL Payne ◽  
GW Lanigan
Keyword(s):  
Plant Tissues ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
General Sense ◽  
Plant Component

Experiments confirmed that galls induced by nematodes (Anguina sp.), which develop in the place of seeds on ryegrass plants, become toxic to animals when colonized by Corynebacterium rathayi. The distribution of the toxin within the galls was determined by measuring the levels in extracts from the plant and from the parasite components. Bioassays showed that the toxicity of the plant component was considerably greater than that of the bacterial component. An amount of toxin constituting a dose lethal to nursling rats was extracted from between 0.15 and 0.25 mg of plant component compared with between 5.52 and 5.75 mg of bacterial component. These results suggest that the toxin is produced in the plant tissues in response to the presence of the bacterium. Furthermore, the extracts inhibited the growth of C. rathayi in vitro, which suggests that the toxin behaves in a general sense like a phytoalexin.

Losses of the digestible components of annual ryegrass (Lolium rigidum Gaudin) during senescence

1990 ◽  
Vol 41 (4) ◽  
pp. 719 ◽  
Author(s):  
RA Ballard ◽  
RJ Simpson ◽  
GR Pearce
Keyword(s):  
Chemical Composition ◽  
Leaf Blade ◽  
Leaf Sheath ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Stem Internode ◽  
Whole Plants ◽  
Grass Sward ◽  
Stem Leaf

Changes in the digestibility and chemical composition of a L. rigidum cv. Wimmera sward sown in May, 1985 were measured from 21 d pre-anthesis (9 Oct.) until 69 d after anthesis (7 Jan.) when the plants were dead. Max. yield of 11.7 t DM/ha was reached 8 d pre-anthesis. The in vitro DM digestibility (IVDMD) of whole plants decreased from 58% at anthesis to 36% 69 d after anthesis. This was associated with a decrease in the IVDMD of stem, leaf blades and sheaths. In the 3rd stem internode, which was considered representative of the stem, the loss of digestible yield was due to loss of DM soluble in neutral detergent (NDS). The NDS consisted mainly of non-structural carbohydrates. Similar losses of NDS contributed to loss of digestibility in the uppermost leaf blade and leaf sheath. The digestibility of NDS was generally 80-95% but in the leaf blade this declined to 45% as NDS was mobilized during leaf senescence. NDF digestibility of the stem declined from 35% at anthesis to 19% when dead; corresponding values for the uppermost leaf blade were 83 and 54%, resp., and for the leaf sheath 46 and 37%, resp. These characteristics of a senescing grass sward are discussed in relation to options for improving digestibility of dead grass pastures.

Production of corynetoxins in vitro by Corynebacterium sp. isolated from annual ryegrass seedheads

1988 ◽  
Vol 39 (1) ◽  
pp. 63 ◽  
Author(s):  
AL Payne ◽  
PA Cockrum
Keyword(s):  
Incubation Temperature ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
In Vitro Production ◽  
The Family ◽  
Agar Surface ◽  
Vitro Production ◽  
Corynebacterium Sp ◽  
Annual Ryegrass Toxicity

Corynetoxin complex is the family of tunicamycin-like antibiotics isolated from annual ryegrass (Lolium rigidum) seedheads infected with a plant pathogenic Corynebacterium and identified as the causative toxins for annual ryegrass toxicity (ARGT) in Australia. Only trace amounts of corynetoxins have been reported to be produced in vitro. Enhanced in vitro production of corynetoxins by Corynebacterium sp. has now been demonstrated. The important conditions required were growth on an agar surface, absence of light, low incubation temperature and strain of the organism. Strains of the Corynebaterium sp. grown under conditions not supporting corynetoxin production failed to produce corynetoxins when subsequently grown under more favourable conditions. Even when maintained under the most favourable conditions, toxigenicity of strains declined on repeated subculturing. While levels of toxin typically produced in vitro were only about 5% of those found in infected ryegrass seedheads, they were high enough to be a useful source of corynetoxins for experimental purposes.

Corynetoxins are not detoxicated by in vitro fermentation in ovine rumen fluid

1986 ◽  
Vol 37 (5) ◽  
pp. 523 ◽  
Author(s):  
P Vogel ◽  
MG McGrath
Keyword(s):  
Rumen Fluid ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Lolium Rigidum ◽  
In Vitro Fermentation ◽  
Bacterial Inhibition ◽  
Annual Ryegrass Toxicity

Tunicamycin and seed galls of annual ryegrass (Lolium rigidum) containing corynetoxins, the causal agents of annual ryegrass toxicity, were incubated in ovine rumen fluid-buffer mixtures. A bacterial inhibition assay of extracted incubation mixtures revealed that no detoxication occurred under these in vitro conditions.

Manipulation of the feeding value of senescing annual ryegrass (Lolium rigidum Gaud.) with imazethapyr and glyphosate

1993 ◽  
Vol 44 (7) ◽  
pp. 1653
Author(s):  
MC Crawford ◽  
RJ Simpson
Keyword(s):  
Dry Matter ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Dry Matter Digestibility ◽  
Herbicide Treatment ◽  
Herbicide Treatments ◽  
Feeding Value ◽  
Control Application ◽  
Days After Anthesis

The effect of applying imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin- 2-y1)nicotinic acid] on the in vitro dry matter digestibility (IVDMD) of annual ryegrass was studied and compared with the effects of glyphosate [N-(phosphonomethyl)glycine] . Application of imazethapyr 20 days before anthesis delayed loss of digestible dry matter (DDM) more effectively than when applied at anthesis or 8 days after anthesis. Digestibility of the stems of ryegrass when measured at anthesis was 57.9% and 61.9% for 50 g (a.i.) ha-1 and 100 g (a.i.) ha-1 of imazethapyr, respectively, compared with 50.4% for the control. Application of either imazethapyr or glyphosate decreased dry matter yield initially, mainly because growth of seed heads was reduced. Both glyphosate- and imazethapyr-treated plants produced secondary tillers. In the case of the imazethapyr-treated plants, yield forgone as a result of herbicide treatment was recovered through the production of secondary tillers and because seed head yield were not suppressed to the same extent as in the gylphosate-treated plants. When applied 20 days before anthesis, both herbicides maintained stem IVDMD at 54-60% for up to 42 days after spraying, whereas IVDMD of stems in the control declined. The IVDMD of leaf sheaths was intermediate between that of stems and leaf blades and was improved by herbicide treatment. The IVDMD of leaf blades was unaffected by herbicide treatment. Herbicide treatments 20 days before anthesis therefore delayed loss of DDWI from the vegetative part of the sward for up to 22 days after anthesis. By comparison, in the untreated sward, DDM was lost at a rate of 34.4 kg per ha per day. The total DDM of swards (including seed heads) in all treatments did not differ.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

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.

scholarly journals Method for maintenance of coffee leaves in vitro for mass rearing of Leucoptera coffeellum (Guérin-Méneville) (Lepidoptera: Lyonetiidae)

2000 ◽  
Vol 29 (4) ◽  
pp. 849-854 ◽  
Author(s):  
Ronaldo Reis Jr. ◽  
Lima ◽  
Evaldo F. Vilela ◽  
Raimundo S. Barros
Keyword(s):  
Plant Growth ◽  
Mass Rearing ◽  
Developmental Cycle ◽  
Plant Tissues ◽  
Distilled Water ◽  
Complete Development ◽  
Detached Leaves ◽  
Leaf Survival ◽  
The Ideal

To accomplish systematic studies with coffee leafminer, it is necessary to establish a mass rearing system under artificial conditions. It is possible to rear this species, from egg to adult, under laboratory conditions, without using coffee seedlings but detached leaves maintained in vitro. Synthetic cytokinins are routinely used for maintenance of plant cell and plant tissues in vitro. Two plant growth regulators, benzyladenin and kinetin, in concentrations 10-6 and 10-7 M were used to mantain the leaves. Green leaves collected in the field were maintained in the solution to be tested. Distilled water served as control. The experiment lasted 30 days, a period longer than the necessary for the complete development of the insect. Both artificial cytokinines indeed increased the lifetime of the coffee leaves, maintaining them green and healthy. Leaves placed in the cages for oviposition were attractive to the insect, with significant number of eggs per leaf. In most cases, eggs resulted in individuals that completed the whole developmental cycle. Tests with regulator in different concentrations with healthy leaves showed efficiency. However, we believe that hormone concentrations to be used with mined leaves should be larger, because these when maintained at 10-7 M leaves did not present a satisfactory lifetime. Therefore, tests with mined leaves with different hormone concentrations should be made to find out the ideal concentration for leaf survival. In our laboratory we are successfully using 10-6 M benzyladenin for the maintenance of mined leaves.

Alleviation of dormancy in annual ryegrass (Lolium rigidum) seeds by hydration and after-ripening

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 968-975 ◽  
Author(s):  
Robert S. Gallagher ◽  
Kathryn J. Steadman ◽  
Andrew D. Crawford
Keyword(s):  
Seed Germination ◽  
Relative Humidity ◽  
Germination Rate ◽  
Dormancy Release ◽  
Annual Ryegrass ◽  
Dormant Seed ◽  
Lolium Rigidum ◽  
Time Model ◽  
Treatment Regimens ◽  
Two Populations

The effect of hydration (priming) treatment on dormancy release in annual ryegrass seeds from two populations was investigated. Hydration duration, number, and timing with respect to after-ripening were compared in an experiment involving 15 treatment regimens for 12 wk. Seeds were hydrated at 100% relative humidity for 0, 2, or 10 d at Weeks 1, 6, or 12 of after-ripening. Dormancy status was assessed after each hydration treatment by measuring seed germination at 12-hourly alternating 25/15 C (light/dark) periods using seeds directly from the hydration treatment and seeds subjected to 4 d postpriming desiccation. Seeds exposed to one or more hydration events during the 12 wk were less dormant than seeds that remained dry throughout after-ripening. The longer hydration of 10 d promoted greater dormancy loss than either a 2-d hydration or no hydration. For the seed lot that was most dormant at the start of the experiment, two or three rather than one hydration event or a hydration event earlier rather than later during after-ripening promoted greater dormancy release. These effects were not significant for the less-dormant seed lot. For both seed lots, the effect of a single hydration for 2 d at Week 1 or 6 of after-ripening was not manifested until the test at Week 12 of the experiment, suggesting that the hydration events alter the rate of dormancy release during subsequent after-ripening. A hydrothermal priming time model, usually used for modeling the effect of priming on germination rate of nondormant seeds, was successfully applied to dormancy release resulting from the hydration treatments.

Annual ryegrass (Lolium rigidum) seed survival and digestibility in cattle and sheep

2002 ◽  
Vol 42 (2) ◽  
pp. 111 ◽  
Author(s):  
R. Stanton ◽  
J. Piltz ◽  
J. Pratley ◽  
A. Kaiser ◽  
D. Hudson ◽  
...  
Keyword(s):  
Dry Matter ◽  
Control Diet ◽  
Basal Diet ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Seed Survival ◽  
Dry Matter Digestibility ◽  
Cattle And Sheep

A trial was conducted to investigate the survival and digestibility of annual ryegrass (ARG) seed (Lolium rigidum L.) eaten by sheep and cattle. Sheep (n= 8) and cattle (n = 8) were fed a basal diet containing 1:1 lucerne chaff:oaten chaff with (ARG) or without (control) the inclusion of 20% total dry matter of annual ryegrass seed in a changeover design. Intake was restricted to 17 g/kg liveweight. Digestibility of the control diet was lower (P<0.01) for sheep than cattle. Annual ryegrass seed was present (P<0.01) in the faeces of both sheep and cattle within 24 h of first ingestion. Some 10.8 and 32.8% of seed ingested was excreted by sheep and cattle respectively, with 3.9% (sheep) and 11.9% (cattle) remaining germinable. Annual ryegrass seed continued to be excreted by both sheep and cattle up to 5 days after removal from the diet. Dry matter digestibility of the annual ryegrass diet was 53% in cattle.

scholarly journals Cross-Resistance to Herbicides in Annual Ryegrass (Lolium rigidum)

1990 ◽  
Vol 94 (3) ◽  
pp. 1180-1186 ◽  
Author(s):  
John M. Matthews ◽  
Joseph A. M. Holtum ◽  
David R. Liljegren ◽  
Barbara Furness ◽  
Stephen B. Powles
Keyword(s):  
Cross Resistance ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Resistance To Herbicides
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