The softening of hard seeds of san-plain lupin (Lupinus varius)

1968 ◽  
Vol 19 (4) ◽  
pp. 507 ◽  
Author(s):  
BJ Quinlivan
Keyword(s):  
Moisture Content ◽  
Temperature Fluctuations ◽  
Dry Weight ◽  
Summer Temperature ◽  
Weight Basis ◽  
Humid Atmosphere ◽  
Moisture Contents ◽  
Hard Seeds ◽  
Sand Plain ◽  
Daily Temperature Fluctuations

Two types of impermeability were found in hard seeds of sand-plain lupin. Hard seeds with a moisture content above 10% (dry weight basis) are conditionally hard. They soften slowly when placed in a humid atmosphere or moist soil, the rate of softening varying directly with the moisture content. Moisture penetration occurs at random sites over the testa, but not normally at the hilum or strophiole. Hard seeds with a moisture content below 8.5%, on the other hand, are absolutely hard, and will not soften as a result of exposure to moist conditions. They will soften, however, if exposed to daily temperature fluctuations between 15 and 65°C, which fracture the impermeable coat at the strophiole. This type of softening does not occur in seeds with a moisture content above 8.5%. It is concluded that under field conditions the autumn germination pattern of the species, which has no physiological seed dormancy, would depend on the degree to which the seeds become desiccated during the summer. Where moisture contents remain above l0%, the seeds would give a scattered germination over several months. With moisture contents below 8.5% the only seeds capable of germinating would be those with a fracture at the strophiole resulting from summer temperature fluctuations. These would all germinate within a few days following moistening of the soil.

Leek (Allium porrum L.) seed development and germination

1992 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
D. Gray ◽  
J. R. A. Steckel ◽  
L. J. Hands
Keyword(s):  
Moisture Content ◽  
Seed Development ◽  
Developmental Stages ◽  
Dry Weight ◽  
Allium Porrum ◽  
Seed Moisture Content ◽  
Subsequent Performance ◽  
Moisture Contents ◽  
Seed Moisture ◽  
Seed Growth

AbstractThe effects of development of leek seeds at 20/10°, 25/15° and 30/20°C (day/night) and drying of seed harvested at different developmental stages on subsequent performance were examined in each of 3 years. An increase in temperature from 20/10° to 30/20°C reduced mean seed weight from 2.90 to 2.55 mg as a result of a reduction in the duration of seed growth from 80 to 55 days; seed growth rate was unaffected. Seed moisture content reached a minimum, up to 35 days after the attainment of maximum seed dry weight and 115, 90 and 70 days after anthesis at 20/10°, 25/15° and 30/20°C, respectively. The curves relating seed moisture to time for each temperature regime were mapped onto a single line accounting for >90% of the variation in moisture content, using accumulated day-degrees >6°C instead of chronological time. Seeds were capable of germinating when seed moisture contents were >60% (fresh weight basis), but maximum viability and minimum mean time to germination were not attained until seed moisture contents at harvest had fallen to 20–30%. Germination was little affected by temperature of seed development. Drying immature seeds increased percentage germination. Growing seeds at 30/20°C and drying at 35°C and 30% RH raised the upper temperature limit of germination compared with growing at 20/10°C and drying at 15°C and 30% RH.

The action of temperature fluctuations on hard seeds of subterranean clover

1971 ◽  
Vol 11 (51) ◽  
pp. 440 ◽  
Author(s):  
MW Hagon
Keyword(s):  
No Reduction ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Specific Region ◽  
Daily Temperature ◽  
Laboratory Conditions ◽  
Hard Seeds ◽  
Cycle Lengths ◽  
Daily Temperature Fluctuations

Burrs of three cultivars of subterranean clover (Trifolium subterraneum) were placed in soil in a cold frame at Canberra so that they were subjected to daily temperature fluctuations of the order of 20-54�C. After three months and eight months the proportion of permeable seeds was significantly increased. Such seeds were conductive to water at one specific region of the testa-the strophiole. In a further experiment, under laboratory conditions, hard seeds were subjected to temperature fluctuations of 23-60�C with cycle lengths varying from 15 minutes to 1 hour. There was no reduction in the percentage of hard seeds except in two trials when that portion of each cycle at 60�C was greater than 45 minutes.

Changes in seed quality during seed development and maturation in tomato

1992 ◽  
Vol 2 (2) ◽  
pp. 81-87 ◽  
Author(s):  
I. Demir ◽  
R. H. Ellis
Keyword(s):  
Lycopersicon Esculentum ◽  
Moisture Content ◽  
Developmental Stage ◽  
Seed Development ◽  
Seed Quality ◽  
Seed Viability ◽  
Dry Weight ◽  
Seed Filling ◽  
Moisture Contents ◽  
Seed Moisture

AbstractChanges in tomato (Lycopersicon esculentumMill.) seed quality were monitored during seed development and maturation in glasshouse experiments in 2 years. The end of the seedfilling period (mass maturity) occurred 35–41 d after anthesis (differing among trusses) in 1989 and 42 d after anthesis in 1990. Seed moisture contents at this developmental stage were 53–72% (wet basis), while the onset of ability to germinate (during 21-d tests at 20°/30°C) and the onset of tolerance to rapid enforced desiccation occurred just before (1990) or just after (1989) mass maturity. In 1989, seed quality was assessed primarily by seedling size in a glasshouse experiment; maximum mean seedling dry weight 25 d after sowing was not achieved until 24–40 d after mass maturity. In 1990, seed quality was assessed primarily by germination following storage; maximum normal germination after 35 d in storage at 40 °C with 14 ± 0.5% moisture content was attained 23 d after mass maturity, but with little difference among seed lots harvested 10 d earlier or up to 30 d later. The results contradict the hypothesis that maximum seed quality is attained at the end of the seed-filling period and that seed viability and vigour begin to decline immediately thereafter.

The effect of moisture content and prechill duration on dormancy breakage of Douglas fir seeds (Pseudotsuga menziesiivar.menziesii[Mirb.] Franco)

2003 ◽  
Vol 13 (3) ◽  
pp. 239-246 ◽  
Author(s):  
Peter G. Gosling ◽  
Yvonne Samuel ◽  
Andrew Peace
Keyword(s):  
Moisture Content ◽  
Weighting Function ◽  
Dry Weight ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Germination Capacity ◽  
Moisture Contents ◽  
Bivariate Spline ◽  
Food Reserves ◽  
Seed Respiration

AbstractSeeds of Douglas fir (Pseudotsuga menziesiivar.menziesii[Mirb.] Franco) were initially germinated at six constant temperatures (10–35°C), following 0–48 weeks incubation under moist conditions at 4°C, i.e. prechill or stratification. The best, single germination temperature was 15°C for determining the efficacy of subsequent dormancy breakage treatments. Seeds from the same seedlot were then adjusted to 10, 15, 20, 25, 30, 35 and 40% moisture contents (mcfw, fresh weight basis), prechilled for 0, 2, 4, 8, 16, 32, 64 and 128 weeks and transferred to 15°C. A smoothed bivariate spline was used to model the results and showed that virtually all combinations of moisture content and prechill duration significantly stimulated germination capacity, but that the optimal germination percentage (≥93%) was stimulated only by various combinations of between 30 and 35% mcfw and 25 and 48 weeks prechill. At optimal moisture contents (30 and 35%) , extending the prechill duration beyond 48 weeks led to a decrease in germination capacity. This was not due to dormancy reintroduction, but was caused largely by seed death. Regression models using a weighting function, to account for differences in standard deviations, demonstrated significant increases in the mean moisture content of individual seeds at higher moisture contents (≥25%) and longer prechill durations (≥64 weeks) that were concomitant with significant decreases in dry weight. The most likely explanation for this was seed respiration. The combined results suggest that dormancy breakage in Douglas fir seeds requires a hydration level sufficient for respiration to take place, and that, after maximal dormancy release, seeds at the highest mc (35–40%) exhaust their food reserves and begin to deteriorate.

scholarly journals The Regulatory Mechanism of 2-Acetyl-1-Pyrroline Biosynthesis in Fragrant Rice (Oryza sativa L.) Under Different Soil Moisture Contents

2021 ◽  
Vol 12 ◽  
Author(s):  
Haowen Luo ◽  
Meiyang Duan ◽  
Leilei Kong ◽  
Longxin He ◽  
Yulin Chen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Growth Parameters ◽  
Oryza Sativa L ◽  
Dry Weight ◽  
Transcript Level ◽  
Fragrant Rice ◽  
Moisture Contents ◽  
Significant Difference

2-acetyl-1-pyrroline (2-AP) is the key compound of rice aroma. However, the responses of 2-AP biosynthesis in fragrant rice under different soil moisture and the corresponding mechanism are little known. The present study evaluated the effects of different soil moisture on 2-AP biosynthesis through a pot experiment. Four soil moisture contents, that is, 50% (SM50), 40% (SM40), 30% (SM30), and 20% (SM20), were adopted, and SM50 treatment was taken as control. The pots were weighed and watered to maintain the corresponding soil moisture content. The results showed no significant difference in growth parameters (plant height, stem diameter, and plant dry weight) among all treatments. Compared with SM50, SM40, SM30, and SM20 treatments significantly (p<0.05) increased 2-AP content by 32.81, 23.18, and 53.12%, respectively. Between 20 to 90% higher proline content was observed in SM40, SM30, and SM20 treatments than in SM50. Enzymes including proline dehydrogenase, ornithine transaminase, and 1-pyrroline-5-carboxylate synthetase exhibited lower activities with soil moisture declined. Higher diamine oxidase activity was observed in SM40, SM30, and SM20 treatments compared with SM50, and real-time PCR analyses showed that transcript level of DAO1 was greatly increased under low soil moisture treatments, especially in SM20 treatment. Transcript levels of PRODH, DAO2, DAO4, DAO5, OAT, P5CS1, and P5CS2 decreased or maintained in SM40, SM30, and SM20 treatments compared with SM50. We deduced that low soil moisture content enhanced 2-AP biosynthesis mainly by upregulating the expression of DAO1 to promote the conversion from putrescine to 2-AP.

scholarly journals Effects of Harvest Date, Storage Temperature, and Moisture Status on Postharvest Needle Retention of Fraser Fir

1988 ◽  
Vol 6 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Elizabeth J. Mitcham-Butler ◽  
L. Eric Hinesley ◽  
David M. Pharr
Keyword(s):  
Moisture Content ◽  
Storage Temperature ◽  
Dry Weight ◽  
Weight Basis ◽  
Harvest Date ◽  
Abies Fraseri ◽  
Fraser Fir ◽  
Needle Retention ◽  
Needle Loss ◽  
Storage Temperatures

Fraser Fir (Abies fraseri (Pursh) Poir.) branches harvested Oct. 3 and Nov. 28, 1984 were stored with and without water at 9, 16, 23 and 30°C (48, 61, 73 and 86°F) for 6 weeks. Branches set in water exhibited minimal needle loss at all temperatures except 30°C (86°F) where 60 to 75% of the foliage detached. Branches without water retained needles better at lower temperatures where the drying rate was slower. Branches without water which were harvested Nov. 28 exhibited less needle loss than those harvested Oct. 3, but storage temperature had more effect than harvest date. Branches with water maintained a moisture content of 120 to 140% (dry weight basis) except those at 30°C (86°F) which decreased to 66% moisture content after 2 weeks. Later harvest date and lower storage temperatures improved postharvest needle retention of Fraser fir.

Bioremediation of PAH-Contaminated Soil via In-Vessel Composting

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2331-2334 ◽  
Author(s):  
A. O. Adenuga ◽  
J. H. Johnson ◽  
J. N. Cannon ◽  
L. Wan
Keyword(s):  
Moisture Content ◽  
Contaminated Soil ◽  
High Performance ◽  
Dry Weight ◽  
Total Radioactivity ◽  
Weight Basis ◽  
Microbial Consortia ◽  
Liquid Chromatograph ◽  
Polycyclic Aromatic ◽  
Pyrene Concentration

This study is being conducted to investigate the biodegradation of polycyclic aromatic hydrocarbons (PAHs) present in contaminated soil using composting technology. Pyrene, a four-ring aromatic hydrocarbon, was chosen as a model PAH compound for the study. Preliminary investigations were carried out to assess the feasibility of soil composting by monitoring (a) carbon to nitrogen (C/N) ratio, (b) microbial consortia diversity, (c) coefficient of permeability and (d) moisture content. The soil was augmented with composted sludge, which was used as a bulking agent and nutrient supplement, in quantities ranging from 0-50% dry weight basis. Tests were conducted in both batch and continuous composters. In the batch composter, forty grams of soil/sludge mixtures in different proportions were spiked with 13.5 mg/kg (dry weight basis) of unlabeled pyrene. The batch composters were aerated and placed in a constant temperature water bath for a period of 21 days. Samples were soxhelet extracted and analyzed on the High Performance Liquid Chromatograph to determine the reduction in pyrene concentration. Analysis of these samples is in progress. In the continuous composter, the soil/sludge mixtures are spiked with both labeled and un-labclcd pyrene to obtain a total radioactivity of 13.5 µci. This process is being monitored for temperature, moisture content, volatile solids and microbial population. Mineralization of pyrene is assessed by quantifying 14CO2 produced.

Maturation of sunflower

1975 ◽  
Vol 15 (77) ◽  
pp. 833 ◽  
Author(s):  
WK Anderson
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Moisture Content ◽  
Oil Content ◽  
New South ◽  
Dry Weight ◽  
Physiological Maturity ◽  
Moisture Contents ◽  
South Wales

Maturation of sunflowers was recorded in two field sowings at Armidale, New South Wales. Measurements were made to define anthesis, the accumulation of dry weight, oil and fatty acids in the achenes and to determine moisture contents and crop appearance associated with achene maturation. It is suggested that anthesis may be described either as its mid-point, i.e. when 50% of capitula exhibit anthesis over half their area, or by its spread, i.e. the time between 50% of capitula commenced anthesis and 50 %completed anthesis. Maximum achene dry weight was reached in the field when the achene moisture content was about 40 and the capitulum moisture content was about 70%. Both achene oil content and the content of the major polyunsaturated fatty acid (linoleic) reached their maxima at about the same time as achene dry weight in the field and this point was thus defined as 'physiological' maturity for sunflowers. It corresponded to when about ten per cent of capitula had turned brown. Production of linoleic and oleic acid was found to predominate in the later stages of achene maturation in both field sowings.

scholarly journals Swelling Characteristics of Compacted Claystone-Bentonite Mixtures

2021 ◽  
Vol 933 (1) ◽  
pp. 012002
Author(s):  
Y F Arifin ◽  
M Arsyad ◽  
H Muslim
Keyword(s):  
Swelling Pressure ◽  
Dry Weight ◽  
Weight Basis ◽  
Load Test ◽  
Dry Density ◽  
Swelling Potential ◽  
Moisture Contents ◽  
Swelling Characteristics ◽  
Radioactive Waste Repositories ◽  
Waste Repositories

Abstract High-density claystone mixtures have been suggested as liners in radioactive waste repositories. However, this material can also be used as a liner in landfills. This study focuses on swelling characteristics of compacted claystone-bentonite at a low density for landfill applications. Claystone was taken from the Banjarbakula landfill project in Banjarbaru. The bentonite used is a commercially available bentonite from Indonesia. Claystone was mixed with 5, 10, 15, and 20% of bentonite on a dry weight basis. The mixture was statically compacted with moisture contents of 10, 15, and 20% to achieve a dry density of 16 kN/m3. A swell-load test was carried out using conventional oedometer equipment to obtain the swelling potential and swelling pressure of the samples. The results show that the swelling potential and swelling pressure increased with an increase in bentonite contents. At a bentonite content of more than 10%, both increased significantly. This research also revealed a linear relationship between swelling potential and swelling pressure.

Fire and the opening of Banksia ornata F. Muell. Follicles

1976 ◽  
Vol 24 (3) ◽  
pp. 329 ◽  
Author(s):  
AM Gill
Keyword(s):  
Moisture Content ◽  
Room Temperature ◽  
Dry Weight ◽  
Field Conditions ◽  
Abscission Layer ◽  
Moisture Contents ◽  
Follicle Rupture ◽  
Eastern Australia ◽  
Water Saturated ◽  
Increasing Temperature

Banksia ornata is a sclerophyll shrub, characteristic of the heaths of south-eastern Australia. Its follicles are almost entirely dependent on fire for rupture and release of seed, although a few open under ambient field conditions. At air-dry moisture content (10-12% oven-dry weight) temperatures in excess of about 75°C are required for the rupture of the abscission layer between the woody valves, the time of exposure necessary for rupture decreasing with increasing temperature. At higher moisture contents rupture is delayed. No rupture occurs when follicles are water-saturated and exposed to a temperature of 100° over long periods. Similarly, no rupture occurs at room temperature when follicles are dried under vacuum (to 1.4% oven-dry weight). After rupture, the extent of valve reflexion is greatest when follicle valves are driest. These results are interpreted as follows. Follicle rupture occurs when tension across the abscission zone exceeds its strength: moisture has a major role in affecting the tension, and temperature a major role in affecting the strength.

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