Germination behaviour in beach spinifex (Spinifex hirsutus Labill.)

1972 ◽  
Vol 20 (3) ◽  
pp. 241 ◽  
Author(s):  
RL Harty ◽  
TJ McDonald
Keyword(s):  
Sea Water ◽  
Field Capacity ◽  
Water Soluble ◽  
Lettuce Seed ◽  
Tetrazolium Chloride ◽  
Chemical Inhibitors ◽  
Eastern Australia ◽  
Pot Trials ◽  
Germination Behaviour ◽  
Germination Experiments

This paper deals with threshing and seed germination studies on hand-harvested beach spinifex (Spinifex hirsutus Labill.). This work was carried out as part of a detailed study of the autecology of beach spinifex, an important pioneer sand stabilizer on beaches and dunes along the coast of eastern Australia. Hammer-milling was suitable for threshing out caryopses from beach spinifex inflorescences, but in the process the caryopses were excessively damaged. A barley de-awning machine produced spikelets (caryopses enclosed in lemma, palea, and glumes plus the base of the associated spine) which were free flowing and therefore suitable for mechanical planting. Laboratory germination experiments disclosed that the caryopses were negatively photoblastic when germinated alone, or enclosed within the spikelet. Alternating thermoperiods (10-25, 15-25, 20-25 ; 10-35, 15-35, 20-35�C) were generally superior to constant thermoperiods (25, 30, 35") in the induction of germination. The germination of caryopses from inflorescences harvested 2 months previously agreed with an estimate of viability made by using tetrazolium chloride. This indicated that beach spinifex seed has no pronounced after-ripening requirements. The rate of germination of caryopses and their germinative capacity were markedly increased when the caryopses were removed from the spikelets. It is likely that germination in the spikelet is inhibited by a slow rate of gaseous exchange between the embryo and the atmosphere. A sensitivity to anaerobic conditions was demonstrated by soaking spikelets for varying periods up to 48 hr in distilled and sea water. Such treatments led to a decrease in germination. Pot trials showed that in waterlogged sand, no appreciable germination occurred below 3.75 cm. In sand held at field capacity, some germination occurred down to the maximum depth tried (8.75 cm), but the best germination was from 2.5 to 3 .75 cm. Soaking spikelets in distilled water for 48 hr and testing the leachate on germinating lettuce seed failed to disclose the presence of water-soluble chemical inhibitors in the spikelets.

scholarly journals Allelopathy of Small Everlasting (Antennaria microphylla): Identification of Constituents Phytotoxic to Leafy Spurge (Euphorbia esula)

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Gary D. Manners ◽  
Donald S. Galitz
Keyword(s):  
Root Growth ◽  
Caffeic Acid ◽  
Leafy Spurge ◽  
Water Soluble ◽  
Euphorbia Esula ◽  
Natural Occurrence ◽  
Lettuce Seed ◽  
Ether Extract ◽  
Small Everlasting ◽  
Antennaria Microphylla

The ether extract of small everlasting (Antennaria microphyllaRydb.) was phytotoxic to lettuce seed root growth and leafy spurge (Euphorbia esulaL. # EPHES) root elongation and cell culture growth. Three phenolic compounds (hydroquinone, arbutin, and caffeic acid) were chromatographically isolated and characterized from the ether extract. Arbutin and caffeic acid were moderately phytotoxic to leafy spurge root growth at 300 ppm (w/v), and hydroquinone was strongly phytotoxic to leafy spurge root growth at 50 ppm (w/v). The observed phytotoxicity of hydroquinone and the high-yield natural occurrence of arbutin, a water soluble, easily hydrolyzed monoglucoside of hydroquinone, in small everlasting is consistent with the participation of these two compounds in the observed allelopathy of small everlasting against leafy spurge.

CHEMICAL CONSTITUENTS IN WILD OAT (Avenu fatua) HULLS AND THEIR EFFECTS ON SEED GERMINATION

1982 ◽  
Vol 62 (1) ◽  
pp. 155-161 ◽  
Author(s):  
FRANK S. CHEN ◽  
JOHN M. MacTAGGART ◽  
RICHARD M. ELOFSON
Keyword(s):  
Seed Germination ◽  
Chemical Constituents ◽  
Short Chain Fatty Acids ◽  
Inhibitory Effect ◽  
Water Soluble ◽  
Nonanoic Acid ◽  
Lettuce Seed ◽  
Wild Oat ◽  
Phenolic Inhibitor ◽  
Lettuce Seed Germination

Aqueous extracts of dormant wild oat (Avena fatua L.) hulls had a weak inhibitory effect on lettuce seed germination. Both paper and thin layer chromatographic analyses of the ether-soluble acidic fraction showed the presence of phenolics and short-chain fatty acids. No abscisic acid was detected. Vanillin, protochatechualdehyde, p-coumaric acid, ferulic acid and caffeic acid were isolated from hull extracts. Vanillin was shown to be the main water-soluble phenolic inhibitor of lettuce seed germination. At a concentration higher than 6.6 × 10−3M, vanillin was found to be more inhibitory than nonanoic acid to both lettuce and wild oat germination. The concentration of phenolics in the hulls does not account for suppression of wild oat seed germination.

Relationship between vigour tests and emergence of soybean when grown under a range of seedbed moisture conditions

1996 ◽  
Vol 36 (1) ◽  
pp. 93 ◽  
Author(s):  
SW Adkins ◽  
M Boersma ◽  
M Law
Keyword(s):  
Seedling Emergence ◽  
Accelerated Aging ◽  
Field Capacity ◽  
Hypocotyl Length ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Eastern Australia ◽  
Growth Room ◽  
Glycine Max L ◽  
Moisture Conditions

Laboratory vigour tests were performed on seed from 4 soybean [Glycine max (L.) Merr.] cultivars coming from commercial crops grown in eastern Australia. The seed from each cultivar had greater than 80% germination and a range in vigour. Vigour tests consisted of the accelerated aging (with or without a seed protectant, Thiram), cold, saturation and hypocotyl length tests. Results were compared with seedling emergence from the same cultivar when planted under growth room conditions (25/20 � 1�C, 14/10 h day/night) at 3 seedbed moisture levels (field capacity, -0.01 MPa; dry, -0.30 MPa; and saturated soil, soil saturated for 48 h, planted then allowed to dry to field capacity). The modified accelerated aging test with Thiram was significantly (P<0.01) correlated with emergence in all 3 seedbed moisture conditions. High vigour seed samples with high accelerated aging germinations emerged well. Overall, the vigour test which ranked the seed samples to give the best indicator of performance under a range of seedbed moisture conditions was the modified accelerated aging test with thiram.

Lactobacillus reuteri DSM 20016: purification and characterization of a cystathionine γ-lyase and use as adjunct starter in cheesemaking

2002 ◽  
Vol 69 (2) ◽  
pp. 255-267 ◽  
Author(s):  
MARIA DE ANGELIS ◽  
ÁINE C. CURTIN ◽  
PAUL L. H. McSWEENEY ◽  
MICHELE FACCIA ◽  
MARCO GOBBETTI
Keyword(s):  
Enzyme Activities ◽  
Lactobacillus Reuteri ◽  
Water Soluble ◽  
Dimethyl Disulphide ◽  
Chemical Inhibitors ◽  
Isoelectric Ph ◽  
Water Soluble Extract ◽  
Temperature Optima ◽  
Dimensional Electrophoresis

A homo-tetrameric ∼160-kDa cystathionine γ-lyase was purified to homogeneity from Lactobacillus reuteri DSM 20016 by four chromatographic steps. The activity was pyridoxal-5′-phosphate dependent and the enzyme catalyzed the α,γ-elimination reaction of L-cystathionine, producing L-cysteine, ammonia and α-ketobutyrate. The enzyme was active towards a range of amino acids and amino acid derivatives, including methionine. The pH and temperature optima were found to be 8.0 and 35 °C, respectively. Isoelectric pH (pI) was ∼5.0 as determined by two-dimensional electrophoresis. Sensitivity to chemical inhibitors was typical of lactococcal cystathionine γ- and β-lyases, except it was inhibited by sulphydryl reagents. The N-terminal sequence was MKFNTQLIHGGNSED, which had 100% homology with cystathionine β-lyase of Lb. reuteri 104R (Accession Number CAC05298). Lb. reuteri DSM 20016, together with 10 other strains of non-starter lactic acid bacteria, was used as adjunct starter in the production of miniature Canestrato Pugliese-like cheeses. After 40 d ripening, the water-soluble extract of the cheeses with added Lactobacillus fermentum DT41 and Lb. reuteri DSM 20016 contained the highest enzyme activities on cystathionine and methionine substrates. Determinations of methanethiol, dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide in the miniature cheeses confirmed the findings of enzyme activities.

The Dynamics of Callitris columellaris/Eucalyptus albens Communities Along the Snowy River and Its Tributaries in South-Eastern Australia

1990 ◽  
Vol 38 (4) ◽  
pp. 403 ◽  
Author(s):  
KA Claytongreene ◽  
DH Ashton
Keyword(s):  
Current Distribution ◽  
Numerical Classification ◽  
South Eastern ◽  
River Region ◽  
Eastern Australia ◽  
Germination Behaviour ◽  
Eucalyptus Albens ◽  
Woodland Communities ◽  
South Eastern Australia

The vegetation in the rain shadow areas of the Snowy River region was studied. Five distinct woodland communities were recognised from a numerical classification, a community dominated by C. columellaris at lower altitudes on north and west aspects, three mixed C. columellaris/E. albens communities which are also aspect and altitude dependent, and a higher altitude, cool aspect, E. albens dominated community. Although C. columellaris and E. albens occupy separate niches, they compete strongly. Contrasting dispersal and germination behaviour between the two species may explain the current distribution and structure of these woodlands.

Recognition and Prevention of Distillate Fuel Emulsions

2006 ◽  
Author(s):  
T. D. Newbound ◽  
A. N. Al-Nasser ◽  
M. P. Sang ◽  
W. J. Carrigan
Keyword(s):  
Gas Turbine ◽  
Microbial Activity ◽  
Red Sea ◽  
Diesel Fuel ◽  
Sodium Sulfate ◽  
Sea Water ◽  
Hydrocarbon Fuel ◽  
Liquid Hydrocarbon ◽  
Water Soluble ◽  
High Concentrations

This paper describes a case study involving chronic plugging of 5μm particulate filters in a gas turbine diesel fuel system in a Red Sea refinery. Rapid plugging of the filters was caused by water-in-diesel emulsions generated in diesel fuel supply tanks. Sludge with a wax-like appearance recovered from the 5 μm filters was, in fact, found to be composed of up to 50 percent water with no significant wax content. X-ray studies of the filter catch solids revealed a variety of iron oxide phases, sodium chloride, and high concentrations of sodium sulfate. Microbial cultures inoculated from storage tank ‘rag’ layers yielded moderate to high counts of general aerobic bacteria (GAB), moderate fungal cultures (yeast and molds) and low sulfate reducing bacteria (SRB). Elemental analysis of water in supply tanks where microbial activity was highest revealed ion concentrations similar to those found in Red Sea water. Sulfur isotope ratios in sulfate from filter catches suggest that much of the sulfate was derived from microbial metathesis of sulfur-bearing hydrocarbons. Frequent contamination of on-shore liquid hydrocarbon fuel tanks with sea water can cause corrosion and create a favorable environment for bacterial growth. Surfactant byproducts of microbial activity are capable of stabilizing emulsions, suspending water soluble salts such as sodium sulfate, and metals such as lead and copper. Copper is well known to promote gum formation, while all of these contaminants are potentially corrosive to gas turbine hot gas path components.

Fates of fruits and seeds of Ligustrum lucidum W.T.Ait. and L. sinense Lour. maintained under natural rainfall or irrigation

2000 ◽  
Vol 48 (6) ◽  
pp. 701 ◽  
Author(s):  
F. D. Panetta
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Field Capacity ◽  
Moisture Regime ◽  
Ligustrum Lucidum ◽  
Natural Rainfall ◽  
Eastern Australia ◽  
Series Of Experiments ◽  
Rainfall Regimes ◽  
Seeds And Fruits

Factors influencing germination and seed survival of Ligustrum lucidum W.T.Ait. and L. sinense Lour., two serious environmental weeds in subcoastal eastern Australia, were investigated in a series of experiments conducted under natural rainfall regimes (field experiments) and under irrigation in a growth tunnel. In the field experiments, no seedlings of either species were observed where seeds and intact fruits had been surface-sown; seedlings originated only from shallowly buried seeds and fruits, with generally higher levels of emergence from seeds. Where soil moisture levels were maintained at or above field capacity, however, moderate to high levels of germination occurred from surface-sown seeds and fruits of both species. Total seedling emergence varied considerably between years for each moisture regime. Seeds of both species were short-lived, with most (>95%) not persisting for 12 months in any case.

scholarly journals Sink-source and sink-sink relations during reproductive development in Lolium perenne L

1997 ◽  
Vol 45 (4) ◽  
pp. 505-520
Author(s):  
J.W. Warringa ◽  
M.J. Marinissen
Keyword(s):  
Dry Mass ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Sink Strength ◽  
Seed Formation ◽  
Seed Filling ◽  
Pot Trials ◽  
Stem Reserves ◽  
Source And Sink ◽  
Final Cutting

In greenhouse pot trials, L. perenne cv. Barlet plants were labelled with 13C at regular intervals from main spike emergence onwards in order to identify and measure the activity of source and sink organs during seed formation. The source activity of the various tiller groups within the plant roughly reflected the relative contributions of these groups to total plant dry mass. After anthesis there was little net exchange of 13C-label between the older and younger tiller groups. From main spike emergence onwards the source activity of the leaves of the reproductive tiller declined sharply, from 95% of total tiller photosynthesis to 16% at final cutting. The spike became the main assimilating organ on the flowering tiller as the leaves aged. During anthesis the stem was a stronger sink than the seeds. At final cutting 70% of the label was located in the stem, when fixed during anthesis. Water-soluble carbohydrates accumulated in the stem, forming up to 25% of dry matter. After anthesis the sink strength of the developing seeds increased and that of the stem decreased and the stem remained a net sink organ up to about mid-seed filling. Pre-anthesis assimilates contributed 14% to final seed and spikelet carbon, when correcting for the palea and lemma that are present before anthesis. These results show that the stem is a temporary storage organ that can support seed filling. However, only a small amount of the stem reserves was used by the seeds. In contrast to carbon, nitrogen was largely redistributed from the stem and leaves to the seeds. At final harvest 59% of the nitrogen in the flowering tiller was located in the seeds.

scholarly journals Global atmospheric oxygen variations recorded by Th/U systematics of igneous rocks

2019 ◽  
Vol 116 (38) ◽  
pp. 18854-18859 ◽  
Author(s):  
He Liu ◽  
Robert E. Zartman ◽  
Trevor R. Ireland ◽  
Wei-dong Sun
Keyword(s):  
Oceanic Crust ◽  
Sea Water ◽  
Atmospheric Oxygen ◽  
Sharp Decrease ◽  
Temporal Variations ◽  
Global Scale ◽  
Significant Rise ◽  
Water Soluble ◽  
Igneous Rocks ◽  
Major Step

Atmospheric oxygen has evolved from negligible levels in the Archean to the current level of about 21% through 2 major step rises: The Great Oxidation Event (GOE) in the early Proterozoic and the Neoproterozoic Oxygenation Event (NOE) during the late Proterozoic. However, most previous methods for constraining the time of atmospheric oxygenation have relied on evidence from sedimentary rocks. Here, we investigate the temporal variations of the Th/U of arc igneous rocks since 3.0 billion y ago (Ga) and show that 2 major Th/U decreases are recorded at ca. 2.35 Ga and ca. 0.75 Ga, coincident with the beginning of the GOE and NOE. The decoupling of U from Th is predominantly caused by the significant rise of atmospheric oxygen. Under an increasingly oxidized atmosphere condition, more uranium in the surface environment became oxidized from the water-insoluble U4+ to the water-soluble U6+ valance and incorporated in the sea water and altered oceanic crust. Eventually, the subduction of this altered oceanic crust produced the low-Th/U signature of arc igneous rocks. Therefore, the sharp decrease of Th/U in global arc igneous rocks may provide strong evidence for the rise of atmospheric oxygen. We suggest that the secular Th/U evolution of arc igneous rocks could be an effective geochemical indicator recording the global-scale atmospheric oxygen variation.

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