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.

Note. Sugar, Moisture Contents, and Color of Chestnuts during Different Storage Regimes

2009 ◽  
Vol 15 (2) ◽  
pp. 169-178 ◽  
Author(s):  
F. Chenlo ◽  
R. Moreira ◽  
L. Chaguri ◽  
M.D. Torres
Keyword(s):  
Moisture Content ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Sugar Content ◽  
Castanea Sativa ◽  
Dry Weight ◽  
Sucrose Content ◽  
Color Changes ◽  
Moisture Contents ◽  
Castanea Sativa Mill

Color, moisture and sucrose, glucose and fructose contents of chestnuts (Castanea sativa Mill.) at several initial states (whole and undried; whole, peeled, and partially air-dried, with or without prior sucrose treatment; peeled, broken, and undried or partially air-dried) were monitored for 11 months during storage under various conditions (unpacked, packed in plastic bags at ambient pressure, or vacuum packed) and temperature (at room temperature, 3°C or -18°C). Moisture content decreased considerably in all cases except in those of packed whole peeled chestnuts without sucrose treatment and stored at room temperature or 3°C. Chestnuts stored for 2 months in contact with the atmosphere had moisture contents of only ∼4% of their dry weight. After 4 months storage, sucrose content had fallen (in some cases to zero) in all samples except in broken chestnuts dried to a 2% moisture content and conventionally stored whole unpeeled chestnuts (in which sucrose content rose slightly). Glucose and fructose contents generally peaked after 1-2 months of storage, and by month 4 returned to initial or lower levels. Sugar content was hardly affected by initial moisture or sugar contents except when moisture content had been reduced to 2%. Color changes were least during storage in air or at 3°C.

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.

Fuelbed ignition potential and bark morphology explain the notoriety of the eucalypt messmate 'stringybark' for intense spotting

2011 ◽  
Vol 20 (7) ◽  
pp. 897 ◽  
Author(s):  
P. F. M. Ellis
Keyword(s):  
Moisture Content ◽  
Pinus Radiata ◽  
Laboratory Tests ◽  
Flight Behaviour ◽  
Outer Bark ◽  
Ignition Probability ◽  
Loss Of Life ◽  
Moisture Contents ◽  
Eastern Australia ◽  
Probability Weight

In south-eastern Australia, bark of the ‘stringybark’ eucalypt group, and notably that of messmate (Eucalyptus obliqua L’Hér.), is notorious for intense spotting and it is likely that firebrands of this type contribute significantly to loss of life and property during major wildfires. The fuelbed ignition potential by glowing samples was laboratory tested on excised sections of Pinus radiata D. Don litterbed at moisture contents between 2 and 8% and for ‘no-wind’ or for ‘wind’ of 1 m s–1. Prepared samples of outer bark between 0.5 and 1.6 g were combusted until they attained ~20% of initial mass before placement. For ‘no-wind’, flaming ignition did not occur and the probability of glowing ignition appeared to depend on the chance of contact with needles. For ‘wind’, the probability of flaming ignition was a function of sample glowing mass and fuelbed moisture content. Its ignition probability, weight-for-weight, appears to exceed that reported for other forest firebrands, including bark of E. globulus Labill. However, it is likely that the notoriety of messmate bark is also due, in part, to its morphology and in-flight behaviour. It is argued that firebrand laboratory tests to date may poorly reflect the ignition potential of similar samples after flight.

Moisture Sorption Characteristics of Dakuwa (Nigerian Cereal/Groundnut Snack)

2013 ◽  
Vol 9 (4) ◽  
pp. 499-504 ◽  
Author(s):  
Ocheme Boniface Ocheme ◽  
Chukwuma Charles Ariahu ◽  
Emmanuel Kongo Ingbian
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Goodness Of Fit ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Sorption Data ◽  
Moisture Contents ◽  
Monolayer Moisture ◽  
Increasing Temperature ◽  
Sorption Characteristics

AbstractThe moisture sorption characteristics of dakuwa at 10, 20, 30 and 400°C were studied. The experimental sorption data obtained were applied to BET, GAB, Oswin and Henderson equations to test fitness of the equations to moisture sorption of dakuwa. The sorption isotherms of dakuwa were type III isotherms (J shaped), and the equilibrium moisture content increased with increasing water activity but decreased with increasing temperature. The BET and GAB monolayer moisture contents all decreased with increasing temperature. For adsorption, the BET monolayer was higher (3.163–4.158 g/100 g solid) than that of GAB (2.931–3.728 g/100 g solid), but for desorption, the GAB monolayer (4.792–7.741 g/100 g solid) was higher than that of BET (3.962–4.480 g/100 g solid). Evaluation of goodness of fit of models revealed that moisture sorption of dakuwa was best modelled by GAB equation.

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.

scholarly journals Effects of Changes in Biopolymer Composition on Moisture in Acetylated Wood

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 719
Author(s):  
Tiantian Yang ◽  
Emil Engelund Thybring ◽  
Maria Fredriksson ◽  
Erni Ma ◽  
Jinzhen Cao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Moisture Content ◽  
Spin Relaxation ◽  
Cell Walls ◽  
Lignin Content ◽  
Theoretical Estimate ◽  
Relaxation Times ◽  
Dry Weight ◽  
Hemicellulose Removal ◽  
Water Saturated

To investigate the effects of changes in biopolymer composition on moisture in acetylated poplar wood (Populus euramericana Cv.), the acetylation of control wood was compared to the acetylation of wood with reduced hemicellulose or lignin content (about 9% reduction of total specimen dry weight in both cases). Time-domain nuclear magnetic resonance relaxometry of water-saturated wood gave spin–spin relaxation times (T2) of water populations, while deuteration in a sorption balance was used to characterize the hydroxyl accessibility of the wood cell walls. As expected, the acetylation of pyridine-swelled wood reduced hydroxyl accessibility and made the cell wall less accessible to water, resulting in a reduction of cell wall moisture content by about 24% compared with control wood. Hemicellulose loss per se increased the spin–spin relaxation time of cell wall water, while delignification had the opposite effect. The combined effect of hemicellulose removal and acetylation caused more than a 30% decrease of cell wall moisture content when compared with control wood. The acetylated and partially delignified wood cell walls contained higher cell wall moisture content than acetylated wood. An approximate theoretical calculation of hydroxyl accessibility for acetylated wood was in the low range, but it agreed rather well with the measured accessibility, while acetylated and partially hemicellulose-depleted and partially delignified wood for unknown reasons resulted in substantially lower hydroxyl accessibilities than the theoretical estimate.

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.

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.

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.

The Effects of Temperature and Humidity on the Physical Properties of Tire Cords

1946 ◽  
Vol 19 (1) ◽  
pp. 233-252
Author(s):  
J. H. Dillon ◽  
I. B. Prettyman
Keyword(s):  
Moisture Content ◽  
Important Variable ◽  
Effect Of Temperature ◽  
Complete Evaluation ◽  
Moisture Contents ◽  
Testing Chamber ◽  
Creep Characteristics ◽  
Basic Facts ◽  
Increasing Temperature ◽  
Complicated Nature

Abstract It may be concluded from the foregoing experiments that measurements of tenacity and stretch at a single relative humidity have little meaning, since the important variable, moisture content, decreases rapidly with increasing temperature. The most revealing representation of tenacity or elongation appears to be as a function of temperature at constant moisture regain. Curves of this .type show that the tenacity of a modern viscose rayon cord decreases with increasing temperature in the range of regains 0–5 per cent. The same general behavior is exhibited by low-stretch cotton cord, but the tenacity vs. temperature curves for medium-stretch cotton cord flatten off at temperatures above 100° C. The tenacity of Fortisan cord decreases rapidly with temperature up to 100° C, and then increases slightly between 100° and 165° C. Nylon cord shows a rapid decrease of tenacity with increasing temperature, but maintains its advantage in tenacity over that of rayon for all temperatures and humidities included in these experiments. For any given temperature, increase of moisture content increases the tenacity of the cotton cords to an extent dependent on the “stretch” of the cord; decreases the tenacity of rayon cord. Fortisan increases in tanacity with increasing moisture content in the lower range of moisture contents (like cotton) and then decreases in tenacity for higher moisture contents (like rayon). The tenacity of Nylon decreases very slightly with increasing moisture content. All of the cord materials investigated, cotton, rayon, Fortisan, and Nylon, increase in stretch (10-pound or ultimate) as the moisture content increases. The effect of temperature at constant regain on stretch, however, is rather complicated. Until a method of measuring stretch with the whole cord continuously within the testing chamber is devised, further conclusions would be unjustified. Analyses of the creep characteristics of the various cord materials on the basis of two arbitrarily defined indices “initial compliance” and “weighted creep” yield several basic facts: The low-stretch cotton cord exhibits lower values of both indices compared to medium-stretch cotton, as might be anticipated from tensile measurements. The rayon cord, however, has a much lower “initial compliance” but a definitely higher “weighted creep,” compared to the low-stretch cotton. The Fortisan cord is comparable in “weighted creep” to low-stretch cotton, but has a much lower “initial compliance”. The Nylon cord has an “initial compliance” approaching that of low stretch cotton, but a much higher “weighted creep”, which is equal to or greater than that of rayon. The elongation increment vs. logarithmic time curves for cotton, rayon, and Fortisan are very nearly linear over the period 0.002–20 hour, but those for Nylon show a tendency to increase in slope at times beyond 1 hour. In conclusion, it may be said that the results of these experiments agree very well with current concepts of the structures of cotton, rayon, and Nylon, and have rather interesting implications in regard to the structure of Fortisan. It is well to remember that a complete evaluation of a tire cord should include dynamic fatigue measurements as well as tensile and creep data. The complicated nature of the fatigue problem, however, necessitates an extended separate discussion which is beyond the scope of this paper.

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