Sensitivity to ethylene as a major component in the germination of seeds of Stylosanthes humilis

2006 ◽  
Vol 16 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Dimas Mendes Ribeiro ◽  
Raimundo Santos Barros
Keyword(s):  
Complete Inhibition ◽  
Free Atmosphere ◽  
Low Concentrations ◽  
Stylosanthes Humilis ◽  
Physiological Dormancy ◽  
Townsville Stylo ◽  
Short Time

Physiological dormancy of scarified seeds of Townsville stylo (Stylosanthes humilisH.B.K.) is broken by ethylene. When the biosynthesis of this gas was impaired by 2-aminoethoxyvinylglycine (AVG) plus Co2+, the response to ethylene at very low concentrations was appreciable in non-dormant seeds and nil in the dormant ones. Complete inhibition of germination of non-dormant seeds occurred only when they were treated with AVG plus Co2+under an ethylene-free atmosphere, a condition in which no trace of the gas in the atmosphere of Erlenmeyer flasks could be detected. Injection of ethylene into that system triggered germination of both dormant and non-dormant seeds, demonstrating a requirement for the gas. Non-dormant seeds were at least 50-fold more sensitive to ethylene than the dormant ones. Perception of ethylene occurred within a very short time (at most 15 min), since exposure of both dormant and non-dormant seeds to the gas, at a steeply declining concentration, sufficed to cause substantial germination.

scholarly journals Effect of the seed coat on dormancy and germination in Stylosanthes humilis H. B. K. Seeds

2017 ◽  
Vol 39 (2) ◽  
pp. 114-122 ◽  
Author(s):  
Izabel de Souza Chaves ◽  
Nilo Cesar Queiroga Silva ◽  
Dimas Mendes Ribeiro
Keyword(s):  
Seed Coat ◽  
Room Temperature ◽  
Low Ph ◽  
Physical Dormancy ◽  
Hard Seed ◽  
Stylosanthes Humilis ◽  
Physiological Dormancy ◽  
Radicle Protrusion ◽  
Townsville Stylo ◽  
Hard Seed Coat

Abstract: Seed of Townsville stylo (Stylosanthes humilis H.B.K.) is known to exhibit a hard seed coat and when freshly harvested also show a physiological dormancy, however, the nature of the co-actions between seed coat and embryo growth that determine dormancy is poorly understood. In this study, physical dormancy of Townsville stylo seeds was not reduced during natural ageing at room temperature, in contrast to the physiological dormancy, which is gradually overcome during after-ripening. Furthermore, the permeability of seed coat was affected by scarification treatments as well as by low-pH solutions. Together, these data indicate that physical dormancy overcome of seed is prerequisite for radicle protrusion and physiological dormancy of Townsville stylo seeds contribute to its timing.

scholarly journals Dormancy breakage of Stylosanthes humilis seeds by aluminium

2010 ◽  
Vol 20 (3) ◽  
pp. 145-152 ◽  
Author(s):  
Dimas M. Ribeiro ◽  
Ana M. Mapeli ◽  
Marcelo A.G. Carnelossi ◽  
Carla A. Delatorre ◽  
Raimundo S. Barros
Keyword(s):  
Ethylene Production ◽  
Methyl Viologen ◽  
Acc Oxidase ◽  
Low Ph ◽  
Sodium Selenate ◽  
Antioxidant Compounds ◽  
Stylosanthes Humilis ◽  
Physiological Dormancy ◽  
Townsville Stylo ◽  
Low Activity

AbstractPhysiological dormancy of scarified seeds of Townsville stylo (Stylosanthes humilis HBK) was released by acidic aluminium (Al3+) solution. Antiethylenic substances inhibited germination of low-pH-stimulated dormant seeds, with a correspondingly low ethylene production and low activity of 1-aminocyclopropane-1-carboxylate (ACC) oxidase in seeds. On the other hand, antiethylenic substances did not decrease the germination of Al3+-stimulated seeds, but ACC oxidase activity and ethylene production by the seeds was decreased to a large extent. These data provide evidence that dormancy breakage by Al3+ differs from that caused by low pH and is not associated with ethylene production. Similarly to Al3+ action, methyl viologen (MV), a reactive oxygen species-generating compound, broke dormancy of Townsville stylo seeds. Sodium selenate and N-acetyl cysteine, antioxidant compounds, largely decreased germination of MV- and Al3+-stimulated dormant seeds. Altogether these data point to oxidative radicals constituting key molecules in the chain of events triggered by Al3+ leading to dormancy breakage.

Sodium Benzoate Inhibits Growth of or Inactivates Listeria monocytogenes

1988 ◽  
Vol 51 (7) ◽  
pp. 525-530 ◽  
Author(s):  
MOUSTAFA A. EL-SHENAWY ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Incubation Period ◽  
Sodium Benzoate ◽  
The Other ◽  
Complete Inhibition ◽  
Initial Population ◽  
Limited Growth ◽  
Complete Inactivation ◽  
Low Concentrations ◽  
Slight Growth

The ability of Listeria monocytogenes to grow or survive was determined using tryptose broth at pH 5.6 or 5.0, supplemented with 0, 0.05. 0.1, 0.15. 0.2. 0.25 or 0.3% sodium benzoate, and incubated at 4,13,21 or 35°C. The bacterium grew in benzoate-free controls under all conditions except at 4°C and pH 5.0. At pH 5.6 and 4°C, after 60 d, L. monocytogenes (initial population ca. 103/ml) was inactivated by 0.2, 0.25 and 0.3% sodium benzoate. Other concentrations of benzoate permitted slight growth during the first 36 d of incubation followed by a decrease in populations of the pathogen. At pH 5.0 and 4°C, from 0.15 to 0.3% benzoate completely inactivated the pathogen in 24 to 30 d, whereas the other concentrations caused a gradual decrease in the population during the 66-d incubation period. At 13°C and pH 5.6, L. monocytogenes grew (more at lower than higher concentrations of benzoate) in the presence of all concentrations of benzoate except 0.25 or 0.3%, which prohibited growth throughout a 264-h incubation period. Reducing the pH to 5.0 minimized growth at the two low concentrations of benzoate and caused slight decreases in population at the other concentrations of benzoate. At 21 and 35°C and pH 5.6, appreciable growth of L. monocytogenes occurred in the presence of 0.2% or less sodium benzoate, whereas higher concentrations were inhibitory, permitting little if any growth by the pathogen. Reducing the pH to 5.0 allowed limited growth of the pathogen at 21 and 35°C when the medium contained 0.05 or 0.1% sodium benzoate. Higher concentrations caused either complete inhibition or inhibition plus partial or complete inactivation of the pathogen during incubations of 117 h at 21°C or 78 h at 35°C.

scholarly journals ZIF Nanocrystal-Based Surface Acoustic Wave (SAW) Electronic Nose to Detect Diabetes in Human Breath

Biosensors ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 4 ◽  
Author(s):  
Fabio Bahos ◽  
Arianee Sainz-Vidal ◽  
Celia Sánchez-Pérez ◽  
José Saniger ◽  
Isabel Gràcia ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Signal Recovery ◽  
Exhaled Breath ◽  
Zeolitic Imidazolate Frameworks ◽  
Saw Sensor ◽  
Low Concentrations ◽  
Control Of Diabetes ◽  
Short Time ◽  
And Control

In the present work, a novel, portable and innovative eNose composed of a surface acoustic wave (SAW) sensor array based on zeolitic imidazolate frameworks, ZIF-8 and ZIF-67 nanocrystals (pure and combined with gold nanoparticles), as sensitive layers has been tested as a non-invasive system to detect different disease markers, such as acetone, ethanol and ammonia, related to the diagnosis and control of diabetes mellitus through exhaled breath. The sensors have been prepared by spin coating, achieving continuous sensitive layers at the surface of the SAW device. Low concentrations (5 ppm, 10 ppm and 25 ppm) of the marker analytes were measured, obtaining high sensitivities, good reproducibility, short time response and fast signal recovery.

The inheritance of flowering time in Townsville stylo (Stylosanthes humilis)

1976 ◽  
Vol 27 (6) ◽  
pp. 825 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Flowering Time ◽  
Dominant Gene ◽  
Diallel Cross ◽  
Early Flowering ◽  
Multiple Alleles ◽  
Locus Model ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Maturity Groups ◽  
Early Flowering Phenotype

The inheritance of flowering time was studied in F1, F2 and F3 populations derived from a diallel cross among nine naturalized Australian lines of Townsville stylo (Stylosnnthes humilis) and in F1 and F2 populations from a small number of crosses between naturalized Australian lines and introductions from Mexico and Brazil. Strong dominance for lateness of flowering was observed in both the (Australian x Australian) and the (Australian x Mexican/Brazilian introductions) crosses, and some F2 and F3 progenies included small numbers of extremely early plants, flowering up to 55 days earlier than the earliest parent. The flowering time distributions of the (Australian x Australian) crosses could be explained by a three-locus model with multiple alleles at two loci. Proposed genotypes for the four maturity groups are as follows: late, LLM2M2EE; late-midseason, LLmmEE; mid-season, l2l2M2M2EE; early, l1l1M1M1EE; very early, LLM2M2ee. Only one major dominant gene for lateness of flowering could be detected from the distribution of the two (Australian x introduced line) F2 populations, but the segregation of extremely early types and the low recovery of the early-flowering phenotype suggested that other gene loci were segregating.

Effect of time of cessation of wet season grazing on Townsville stylo-annual grass pasture at Katherine, N.T

1973 ◽  
Vol 13 (64) ◽  
pp. 544 ◽  
Author(s):  
MJT Norman ◽  
LJ Phillips
Keyword(s):  
Dry Matter ◽  
Recovery Period ◽  
Dry Matter Yield ◽  
Annual Grass ◽  
Wet Season ◽  
Active Growth ◽  
Heavy Grazing ◽  
Stylosanthes Humilis ◽  
Dry Conditions ◽  
Townsville Stylo

A Townsville stylo (Stylosanthes humilis)-annual grass pasture at Katherine, N.T., was subjected to a series of treatments in 1969-70 and 1970-71 under which plots were grazed heavily from the beginning of the wet season for a period and then allowed to recover undefoliated for the remainder of the season. The dates at which heavy grazing ceased were spaced at 2-week intervals from November 24 to March 16. At the end of the wet season, total dry matter yield was linearly related to length of recovery period. Townsville stylo yield declined as recovery period was reduced from 18 to 8 weeks, but showed little response to a further reduction to 4 weeks. In contrast, annual grass yield showed little change as recovery period was reduced from 18 to 8 weeks, but fell with a further reduction to 4 weeks. As a result, the proportion of Townsville stylo in the pasture at the end of the season was high with long and short recovery periods but reached a minimum with an 8 - 10 week recovery period. Dry conditions prevailed in the first half of both seasons. The evidence suggests that young Townsville stylo is sensitive to heavy grazing when under water stress, and that early grazing for grass control should be imposed only during periods of active growth.

Herbicides for weed control in grain sorghum crops in the Northern Territory

1970 ◽  
Vol 10 (46) ◽  
pp. 588
Author(s):  
IMW Wood
Keyword(s):  
Good Control ◽  
Dry Weight ◽  
Grain Sorghum ◽  
Northern Territory ◽  
Research Station ◽  
Wet Season ◽  
Grain Yields ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Grass Weed

In experiments conducted in the 1968-69 wet season at the Katherine Research Station, Northern Territory, a number of herbicides gave good control of the grass weed Pennisetum polystachyon in grain sorghum crops. Linuron at 3 lb a.i. an acre and PCP at 20 lb a.i. an acre as pre-emergence applications effectively controlled grasses with no apparent adverse affects on the crop. With both there were significantly higher grain yields than on unweeded control plots containing an average of 1378 lb dry weight of P. polystachyon an acre. Fluometuron at 3 lb a.i. an acre late pre-emergence and early post-emergence and chlorthal at 7 lb a.i. an acre pre-emergence controlled grasses but did not increase grain yields. Further investigations are warranted with these herbicides, as banded applications to the interrow may overcome the apparent problem of crop phytotoxicity. Chlorthal at rates that gave good grass control had no adverse effect on Townsville stylo (Stylosanthes humilis). This could be an important advantage when sorghum is sown in rotation with Townsville stylo pasture or where the crop is undersown with Townsville stylo.

The initial and residual responses to phosphorus fertilizers of Townsville stylo in pure ungrazed swards at Katherine, N.T

1972 ◽  
Vol 12 (58) ◽  
pp. 488 ◽  
Author(s):  
MJ Fisher ◽  
NA Campbell
Keyword(s):  
Field Experiment ◽  
Residual Effects ◽  
Yield Data ◽  
Christmas Island ◽  
Stylosanthes Humilis ◽  
Phosphorus Fertilizers ◽  
Nitrogen Concentrations ◽  
Townsville Stylo ◽  
Residual Values ◽  
Second Year

The response of a pure sward of Townsville stylo (Stylosanthes humilis) to various initial and annual dressings of both superphosphate and calcined Christmas Island C-grade phosphate (CCICP) was determined in a field experiment at Katherine, N.T. Townsville stylo responded to superphosphate up to at least 750 kg ha-1. Initial responses and residual effects in the second year and three-year totals were much greater with superphosphate than with CCICP. CCICP gave very variable yields in the second and third years. Nitrogen concentrations were not affected by applied phosphorus but phosphorus concentrations were increased, more by superphosphate than by CCICP. Residual values of superphosphate were derived from Mitscherlich curves fitted to phosphorus yield data, and from these it was determined that 250 kg ha-1 initial and 100 kg ha-1 annual dressing of superphosphate would give stable uptake of phosphorus at the same level as 250 kg ha-1 in the initial year.

Nitrogen accretion and other soil changes in Tindall clay loam under Townsville stylo/grass pastures

1976 ◽  
Vol 16 (78) ◽  
pp. 94 ◽  
Author(s):  
RJK Myers
Keyword(s):  
Organic Carbon ◽  
Available Phosphorus ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Available Nitrogen ◽  
Absolute Value ◽  
Stylosanthes Humilis ◽  
Loam Soil ◽  
Townsville Stylo ◽  
Soil Changes

Soil changes after 3-15 years of fertilized leguminous pastures on Tindall clay loam soil at Katherine, N.T. were studied by comparison of leguminous pasture soils with their native counterparts. Soil organic carbon, total nitrogen, C/N ratio and pH were unchanged by the presence of Townsville stylo (Stylosanthes humilis). Available phosphorus (bicarbonate extraction) was significantly higher under legume pasture, reflecting its fertilizer history, but there was no pattern of increase with time, nor with quantity of fertilizer. Available nitrogen (boiling water extraction) was higher under legume pasture, and both the absolute value under legume pasture and the change in amount were correlated significantly with the age of the pasture. Available nitrogen after three years of legume pasture was equal to that under unimproved pasture, suggesting that gains in this period merely balanced losses during clearing and establishment.

Effect of time of sowing on flowering and growth of Townsville stylo (Stylosanthes humilis)

1974 ◽  
Vol 14 (67) ◽  
pp. 182 ◽  
Author(s):  
Mannetje L t ◽  
KHLvan Bennekom
Keyword(s):  
Low Temperatures ◽  
Dry Matter ◽  
Late Summer ◽  
Growing Season ◽  
Sowing Date ◽  
Stylosanthes Humilis ◽  
Maturity Type ◽  
Townsville Stylo ◽  
Late Start ◽  
Spring Sowing

A midseason maturity type of Townsville stylo sown at monthly intervals throughout a year in a glasshouse in Brisbane (27�30' south) started flowering from 42 to 76 days after sowing between February and September, with dry matter yields at flowering ranging from 0.05 to 5.82 g/per plant. Sowings between October and January resulted in flowering after 98 to 157 days, with yields ranging from 26.41 to 54.75 g/per plant. Flowering was mainly determined by daylength, although low temperatures during winter delayed inflorescence elongation. Growth after onset of flowering was measured in plants sown in winter, spring and late summer. Plant weights increased after flowering in all sowings. In the spring sowing this consisted entirely of stem and inflorescence, but in the other sowings leaf was formed after onset of flowering as well. Winter and spring sowings gave the highest, late summer sowing the lowest final yields. The main agronomic implication is that sowing early in the growing season is necessary for obtaining a good first year's yield, but that seed production is little affected by sowing date, ensuring good regeneration even in years with a late start of the growing season.

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