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

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.

1992 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
D. Gray ◽  
J. R. A. Steckel ◽  
L. J. Hands

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.


2020 ◽  
Vol 26 (5) ◽  
pp. 200361-0
Author(s):  
Sinduja Boopathy ◽  
Merline Sheela Appavoo ◽  
Ilamathi Radhakrishnan

To remediate crude oil-contaminated soil, poultry droppings and sunflower seed husk were incorporated at various concentrations. Initially, the pH, moisture content, total organic carbon (TOC), total nitrogen content, and bacterial population of soil, poultry droppings, and sunflower seed husk were determined. The initial bacterial population was 35 × 10<sup>8</sup> colony forming units/g soil (dry weight basis). The total petroleum hydrocarbon (TPH) content in crude oil-contaminated soil was 7,048.4 mg/kg, in which 857.9 mg/kg accounted for eicosane. Naphthalene and acenaphthalene were the two polyhydroxy aromatic hydrocarbons present in soil at low concentrations. After the amendment, the pH, moisture content, microbial population, and TPH content of soil were determined on days 20, 40, and 60. The TPH concentration was considerably decreased in the treatment T4 wherein 250 g of soil was mixed with 125 g of poultry droppings and 125 g of sunflower seed husk. The indigenous bacterial population was also increased tremendously. The dehydrogenase enzyme activity was increased in the amended soil (T4: 0.74 ± 0.06 μg TPF/g/h). After the treatment of soil, the germination percentage and vigour index of maize, lady’s finger and tomato seeds were enhanced.


Author(s):  
M Kamruzzaman ◽  
S Khatun ◽  
A Rakib ◽  
MI Hoque ◽  
MH Rani

The experiment was conducted to investigate the seed quality of Indian spinach for three months stored at different containers (Plastic pot, polythene bag and cloth bag) during 2013-2014 at Seed Technology Laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur. The initial moisture content of the seed was 9.89% with 75.00% germination. However, after two months, the seed had a different range of increased moisture content with reduced germination percentage depending upon the packing materials. Among the three containers, seeds stored at cloth bag absorbed more moisture (14.36%) from surrounding atmosphere followed by the moisture content, 12.67% and 11.50% of polythene bag and airtight plastic pot, respectively. Seeds stored at plastic pot, polythene bag and cloth bag exhibited 65.00, 64.00 and 50.00 per cent germination, respectively. Similarly, the fresh weight and dry weight of seedling and seedling vigor were also decreased. The seeds of plastic pot were good in term of germination capacity, fresh and dry weight and vigor index in comparison to those stored at cloth bag and polythene bag.Int. J. Agril. Res. Innov. & Tech. 5 (2): 51-57, December, 2015


1970 ◽  
Vol 44 (3) ◽  
pp. 303-310
Author(s):  
A Khatun ◽  
MAH Bhuiyan ◽  
MM Ud-deen

Laboratory experiments were carried out to determine the effects of harvesting stages on the seed quality of chickpea. Chickpea seed of three varieties (BARI Chola-5, BARI Chola-6 and BARI Chola-8) were collected at three harvestings times i.e. from three different times at 7 days interval prior to harvesting, viz. i) when the pods were yellowish with a few yellow greens (H1 stage), ii) when most of the pods were light brown with a few yellow (H2 stage), and iii) when all the pods were completely brown and dry (H3 stage). Significant variation was observed in three varieties of chickpea for all the parameters studied except vigour-I. The highest germination percentage, root length, shoot length, root plus shoot length and vigour-II was observed in BARI Chola-5 which was significantly higher over BARI Chola-8. Dry weight was found to be significantly higher in BARI Chola-8 which was identical to BARI Chola-6. Moisture content was significantly higher in BARI Chola-8. Seed collected at the stage when most of the pods were light brown with a few yellow (H2 stage) recorded the highest germination percentage, dry weight, vigour-I and root length. Pods (H1 stage) gave the highest moisture content in seeds. BARI Chola-5 seeds recorded the highest germination at H2 stage. Interaction effects of varieties and harvesting stage had non-significant effect on germination percentage, vigour-I, shoot length and vigour-II in both the years. Keywords: Chickpea, Harvesting stage, Storage, Vigour, Moisture, Germination DOI: 10.3329/bjsir.v44i3.4403 Bangladesh J. Sci. Ind. Res. 44(3),303-310, 2009  


2013 ◽  
Vol 85 (1) ◽  
pp. 295-306 ◽  
Author(s):  
Edson Simão ◽  
Adriana T. Nakamura ◽  
Massanori Takaki

This study evaluated the contributions of Styrax camporum seed morphology (size of seeds, presence or absence of endocarp attached to the seed), different substrates (filter paper, vermiculite, sand and the soils of cerrado s. str., cerradão and a riparian forest), different water potentials (0, -0.1, -0.2, -0.3, -0.4 and -0.5 MPa), light and temperature to seed germination. Seed size did not affect the germination percentage when seeds were sown on vermiculite. Seeds were affected by small variations in the moisture content of the tested substrates, showing a significant decrease in germination under water potentials lower than -0.1 MPa, close to the field capacity of cerrado s. str. soils. At the temperatures of 15 and 20°C, a significant decrease in germination was observed. Thus, the availability of water in cerrado soils associated to temperature modulate the distribution of germination in this species. Seed morphology contributes to the maintenance of seeds in the soil, and the lack of synchrony in seed germination spreads the distribution of germination in time. These peculiarities allow the emergency of seedlings at different time periods and establishment conditions, an adaptative response of S. camporum to the cerrado environment.


1992 ◽  
Vol 2 (2) ◽  
pp. 81-87 ◽  
Author(s):  
I. Demir ◽  
R. H. Ellis

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.


1976 ◽  
Vol 54 (10) ◽  
pp. 1152-1162 ◽  
Author(s):  
Robert Fogel

Sporocarp phenology of hypogeous or subterranean fruiting fleshy fungi was studied between March 1972 and March 1975 in a 40- to 65-year-old Douglas fir stand in western Oregon. Estimates of yearly productivity ranged from 11052 to 16753 sporocarps ha−1 and 2.3 to 5.4 kg dry weight ha−1. The productivity curve was bimodal as a result of temperature and moisture effects, with peaks in May–June and October. Eleven hypogeous ascomycete species and 13 hypogeous basidiomycete species were collected during the study. Major species that each accounted for 5% or more of the total weight were Tuber murinum, Hymenogaster parksii, Hysterangium crassum, H. separabile, and Truncocolumella citrina var. citrina. Sporocarp moisture content as determined for several species presumably varied with sporocarp age and soil moisture content and ranged from 17.4 to 88.6%. Hypogeous sporocarps had substantially higher macronutrient contents of N, P, and K plus the micronutrients Fe and Al than did epigeous sporocarps of Fomes pinicola. Sporocarp numbers increased exponentially with distance from nearest live Douglas fir stem to a peak at 160 to 200 cm, beyond which numbers dropped sharply. The optimum sporocarp zone was slightly less than the average midpoint between tree stems (205 cm).


1968 ◽  
Vol 19 (4) ◽  
pp. 507 ◽  
Author(s):  
BJ Quinlivan

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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Haowen Luo ◽  
Meiyang Duan ◽  
Leilei Kong ◽  
Longxin He ◽  
Yulin Chen ◽  
...  

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&lt;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.


1975 ◽  
Vol 15 (77) ◽  
pp. 833 ◽  
Author(s):  
WK Anderson

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.


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