Time Requirement from Pollination to Seed Maturity in Waterhemp (Amaranthus tuberculatus)

Weed Science ◽  
2010 ◽  
Vol 58 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Michael S. Bell ◽  
Patrick J. Tranel
Keyword(s):  
Seed Weight ◽  
Room Temperature ◽  
Coat Color ◽  
Seed Viability ◽  
Time Requirement ◽  
Seed Maturity ◽  
Time Period ◽  
Amaranthus Tuberculatus ◽  
Time Required ◽  
Mature Seeds

Experiments were conducted to determine the amount of time required for waterhemp to produce mature seeds after pollination. Female waterhemp plants were pollinated over a 24-h time period and then isolated from males. Two branches, each containing at least 500 flowers, were harvested from each female at the time of the initial pollination, designated as 0 d after pollination (DAP), as well as at multiple other times after pollination up to 62 DAP. One branch from each harvest was stored at 30 C for 48 h, while the other branch was stored at −20 C for 48 h. Branches were then stored at room temperature until all harvests were complete, at which time seeds from each branch at each time after pollination were collected, weighed, and stratified. Germination tests were then conducted to determine the time at which seeds become viable after pollination. Seeds that had not germinated by the end of the germination tests were subjected to tetrazolium testing for viability. Germination tests were also conducted on nonstratified seeds to investigate changes in seed dormancy that were expected to occur over the amount of time the seeds were allowed to remain on the plants. Seeds stored initially at 30 C postharvest became viable 7 to 9 DAP, whereas seeds stored initially at −20 C postharvest did not become mature until 11 DAP. Seed coat color was white soon after pollination and became dark brown to nearly black by 12 DAP, and seed weight increased until 12 DAP. Tetrazolium tests for seed viability correlated well with the germination tests. Germination tests on nonstratified seeds indicated that dormancy level was initially high in the population used, but began to decrease between 15 and 30 DAP. Results of this study have implications both for waterhemp management and research.

scholarly journals Viabilitas Biji dan Pertumbuhan Bibit Kelor (Moringa oleifera Lam.)

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Bambang Budi Santoso ◽  
IGM Arya Parwata
Keyword(s):  
Experimental Research ◽  
Seed Weight ◽  
Moringa Oleifera ◽  
Seed Viability ◽  
Maturity Level ◽  
Seed Maturity ◽  
Seed Position ◽  
Growth Of Seedlings ◽  
Moringa Oleifera Lam

Buah kelor (Moringas oleifera L.) yang secara fisik berukuran panjang dan memiliki banyak biji di dalamnya tentu akan menyebabkan perbedaan tingkat kematangan biji dan kemudian perbedaan pada viabilitas benih yang dihasilkan. Penelitian ekperimental ini terdiri atas dua percobaan, yaitu percobaan pertama bertujuan mengetahui viabilitas biji dari tiga posisi biji dalam buah dan percobaan kedua bertujuan mengetahui pertumbuhan bibit tanaman kelor hingga umur dua bulan dari masing-masing posisi biji pada buah tersebut. Hasil penelitian menunjukkan bahwa posisi biji dalam buah kelor berpengaruh nyata terhadap viabilitas benih, namun berpengaruh tidak nyata terhadap pertumbuhan bibit hingga umur dua bulan. Biji-biji pada posisi di pangkal dan tengah dari buah memiliki viabilitas lebih baik dibandingkan biji-biji pada posisi di ujung buah.Kata kunci: berat biji, pemasakan, perkecambahan, posisi biji ABSTRACTFruits of Moringas oleifera L. is physically long and has many seeds in would certainly cause differences in seed maturity level and then difference in seed viability. This experimental research consisted of two experiments, the first experiment was aimed to find out the seed viability of the three seed positions in the fruits and the second experiment was aimed to determine the growth of the Moringa seedlings up to two months age from each seed position. The results shows that the seed position was significantly affected the viability of the seeds, but were not affected to the growth of seedlings until the age of two months. The seeds in position at the base and the middle of the fruit have better viability than the seeds in position at the end of the fruit.Key words: germination, seed position, ripening, seed weight

scholarly journals BIOCHEMICAL ANALYSES OF SEED EXUDATES DURING EARLY IMBIBITION

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 684g-685
Author(s):  
Eric E. Roos ◽  
Sharon Sowa ◽  
Kristin Pedas
Keyword(s):  
Oryza Sativa ◽  
Protein Concentration ◽  
Room Temperature ◽  
Seed Viability ◽  
Distilled Water ◽  
Short Term ◽  
Time Period ◽  
High Viability ◽  
Biochemical Analyses ◽  
Bca Assay

Short term soaking of seeds does not appear to be detrimental to seed viability and may provide a means of testing seed viability non-destructively. Seeds of corn (Zea mays L.) and rice (Oryza sativa L.), differing in viability, were soaked for 0.5, 1, 2 and 4 hr in distilled water at room temperature. Analyses of pH, protein/polypeptides (BCA assay and absorbance at 280 nm), and potassium (and other metals), were done on individual seed leachates. After each time period seeds were germinated for 7 d to determine viability. For both corn and rice, pH remained constant between 0.5 and 4 hr of soaking. Protein concentration gradually increased during the 4 hr soak in both corn and rice, but varied with seed lot. Potassium was the most common metal excreted and increased 3 to 4 fold between 0.5 and 4 hr of soaking. Although seed to seed variability in any given lot was high, in general, low viability seeds lost more cellular constituents than high viability seeds.

THE EFFECT OF SEED MATURITY, STORAGE ON THE SOIL SURFACE, AND BURIAL ON SEEDS OF Thlaspi arvense L.

1984 ◽  
Vol 64 (4) ◽  
pp. 961-969 ◽  
Author(s):  
L. HUME
Keyword(s):  
Seed Coat ◽  
Coat Color ◽  
Soil Surface ◽  
Storage Conditions ◽  
Seed Coat Color ◽  
Thlaspi Arvense ◽  
Seed Maturity ◽  
Immature Seeds ◽  
Mature Seeds ◽  
Days After Anthesis

The development and germination of immature stinkweed (Thlaspi arvense L.) seeds were investigated under greenhouse and field conditions. In the greenhouse test, there was nearly 100% germination of seeds with a maturity of 15–16 days after anthesis. Seeds from clipped plants buried at 8 cm for 2–5 wk were lighter in weight than either seeds from plants clipped and stored on the soil surface or seeds collected immediately after clipping. Storage conditions influenced both seed coat color and dormancy. Mature seeds from plants stored on the ground turned dark reddish brown, while those from plants stored under the soil turned black. Storage under either set of conditions decreased the dormancy of stinkweed seeds compared to the controls. The more mature seeds from the field-grown populations were more dormant than those from plants grown in the greenhouse, and had slower germination rates. Immature green seeds only 6 days past anthesis were capable of germinating and producing seedlings. It is suggested that for control of stinkweed plants, cultivation should be carried out within 6 days following anthesis of the first stinkweed flowers.Key words: Immature seeds, stinkweed, dormancy

scholarly journals Characterization of Short-Term Temperature, Exposure, and Solubilization Effects on Library Compound Quality

2011 ◽  
Vol 16 (9) ◽  
pp. 1112-1118 ◽  
Author(s):  
John W. Eschelbach ◽  
Dorothy Zhuomei ◽  
Breanne Grady ◽  
Wolfgang Goetzinger
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Demand ◽  
Short Term ◽  
Time Period ◽  
Temperature Exposure ◽  
Time Required ◽  
Storage Times ◽  
The Impact

Many compound collections are stored under the same temperature conditions, which can limit flexibility by increasing the processing time required for high-demand compounds. In this study, the authors wanted to evaluate the impact of a hybrid-storage approach where high-demand compounds are stored for a shortened time period at room temperature to expedite processing operations. The use of a Covaris adaptive-focused acoustics platform was also characterized as a potential enhancement or alternative to storage at elevated temperatures. This study evaluated the impact of temperature, exposure, and solubilization on overall compound quality for short-term storage. A small library of 25 representative compounds was evaluated over an 18-week period to monitor the change in purity and concentration by high-performance liquid chromatography with ultraviolet detection. The authors concluded that temperature had a significant impact on compound concentration, and the effects due to exposure cycles were minimal. A storage time of 12 weeks at room temperature resulted in minimal compound loss, but storage times beyond this would be unacceptable because of a >20% decrease in concentration. Finally, the acoustic solubilization protocol also increased the number of compounds at the target concentration with no impact on overall purity, leading to a potential for increased storage times at frozen temperatures.

Clinical Update: Functional Capacity Evaluations—An Update

1999 ◽  
Vol 4 (5) ◽  
pp. 4-7 ◽  
Author(s):  
Laura Welch
Keyword(s):  
Job Performance ◽  
Functional Capacity ◽  
Injury Risk ◽  
Disability Evaluation ◽  
Time Period ◽  
Submaximal Effort ◽  
Lack Of Sleep ◽  
Overall Performance ◽  
Time Required ◽  
Specific Limitation

Abstract Functional capacity evaluations (FCEs) have become an important component of disability evaluation during the past 10 years to assess an individual's ability to perform the essential or specific functions of a job, both preplacement and during rehabilitation. Evaluating both job performance and physical ability is a complex assessment, and some practitioners are not yet certain that an FCE can achieve these goals. An FCE is useful only if it predicts job performance, and factors that should be assessed include overall performance; consistency of performance across similar areas of the FCE; consistency between observed behaviors during the FCE and limitations or abilities reported by the worker; objective changes (eg, blood pressure and pulse) that are appropriate relative to performance; external factors (illness, lack of sleep, or medication); and a coefficient of variation that can be measured and assessed. FCEs can identify specific movement patterns or weaknesses; measure improvement during rehabilitation; identify a specific limitation that is amenable to accommodation; and identify a worker who appears to be providing a submaximal effort. FCEs are less reliable at predicting injury risk; they cannot tell us much about endurance over a time period longer than the time required for the FCE; and the FCE may measure simple muscular functions when the job requires more complex ones.

A Facile, Efficient and Selective Deprotection of P - Methoxy Benzyl Ethers Using Zinc (II) Trifluoromethanesulfonate

2019 ◽  
Vol 16 (12) ◽  
pp. 955-958
Author(s):  
Reddymasu Sireesha ◽  
Reddymasu Sreenivasulu ◽  
Choragudi Chandrasekhar ◽  
Mannam Subba Rao
Keyword(s):  
Room Temperature ◽  
Protecting Groups ◽  
Side Reactions ◽  
Reaction Conditions ◽  
Acid Sensitivity ◽  
Time Period ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Last Stage ◽  
Zinc Triflate

: Deprotection is significant and conducted over mild reaction conditions, in order to restrict any more side reactions with sensitive functional groups as well as racemization or epimerization of stereo center because the protective groups are often cleaved at last stage in the synthesis. P - Methoxy benzyl (PMB) ether appears unique due to its easy introduction and removal than the other benzyl ether protecting groups. A facile, efficient and highly selective cleavage of P - methoxy benzyl ethers was reported by using 20 mole% Zinc (II) Trifluoromethanesulfonate at room temperature in acetonitrile solvent over 15-120 min. time period. To study the generality of this methodology, several PMB ethers were prepared from a variety of substrates having different protecting groups and subjected to deprotection of PMB ethers using Zn(OTf)2 in acetonitrile. In this methodology, zinc triflate cleaves only PMB ethers without affecting acid sensitivity, base sensitivity and also chiral epoxide groups.

A modified bioassay for heat-stable Escherichia coli enterotoxin

1977 ◽  
Vol 23 (3) ◽  
pp. 331-336 ◽  
Author(s):  
S. Stavric ◽  
D. Jeffrey
Keyword(s):  
Escherichia Coli ◽  
Body Weight ◽  
Incubation Time ◽  
Evans Blue ◽  
Room Temperature ◽  
Blue Dye ◽  
Evans Blue Dye ◽  
Heat Stable ◽  
Stomach Distention ◽  
Time Required

Infant mice were injected orally with preparations containing Escherichia coli heat-stable enterotoxin (ST) and Evans blue dye, and incubated at 22 °C. With enterotoxin-positive samples, the stomach was distended and contained essentially all of the dye. With enterotoxin-negative samples, the stomach remained normal in size and the dye passed freely into the intestines. The time required to obtain the maximum ratio of gut weight to body weight varied from 30 to 90 min and was dependent upon the concentration of enterotoxin. Heat-labile enterotoxin (LT) had no effect during this period.Based on these findings, the mouse incubation time was reduced from 4 h to 90 min, and the heating of test samples was retained only for confirmation of ST. The location of the dye and stomach distention served as an indicator of positive responses to ST. Incubation of the mice at room temperature (22 °C) was found satisfactory.

scholarly journals The Effect of Tillage Treatments on Soil Temperature at Planting and on Corn (Zea mays L.) Yield

2001 ◽  
pp. 40-44
Author(s):  
Miklós Pakurár ◽  
László Lakatos ◽  
János Nagy
Keyword(s):  
Zea Mays ◽  
Soil Temperature ◽  
Zea Mays L ◽  
Time Period ◽  
Soil Temperatures ◽  
Time Periods ◽  
Time Required ◽  
Corn Hybrid

The effect of soil temperature was evaluated on the yield of the Occitan corn hybrid at a depth of 5 cm. We examined this effect on the time required from planting to emergence for three average durations: five, ten and fifteen days, all calculated from the day of planting. Winter plowing (27 cm), spring plowing (23 cm), disc-till (12 cm) treatments and 120 kg N per hectare fertilizer were applied. As a result of our analysis, we determined the post planting optimum soil temperatures for various time periods. The average soil temperature for a time period of 15 days post planting is the most usable for determining actual yields, followed by ten days, with five days proved to be the least usable (winter plow R2 = 0.86, spring plow R2 = 0.87, disc-till R2 = 0.64).

Conductivity, Electrodeposition and Magnetic Property of Cobalt(II) and Dysprosium Chloride in Zinc Chloride-1-Ethyl-3-Methylimidazolium Chloride Room Temperature Molten Salt

2003 ◽  
Vol 58 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Hsin-Yi Hsu ◽  
Chao-Chen Yang
Keyword(s):  
Zinc Chloride ◽  
Room Temperature ◽  
Deposition Potential ◽  
Nucleation Density ◽  
Alloy Electrodeposition ◽  
Viscosity Increase ◽  
Different Temperatures ◽  
Time Required ◽  
Computerized System ◽  
Zn Alloy

Abstract Electric conductivity of the molten zinc chloride-1-ethyl-3-methylimidazolium chloride phases has been measured by a computerized system using the d.c. four-probes method. The sequence of the conductivities for the different component melts is ZnCl2-EMIC > ZnCl2-EMIC-CoCl2 > ZnCl2- EMIC-DyCl3 > ZnCl2-EMIC-CoCl2-DyCl3. The results may be explained in terms of the viscosity increase due to the complex formation. The electrochemistry and the nucleation mechanism of cobalt(II) or/and dysprosium chloride in acidic ZnCl2-EMIC melts have been investigated by cyclic voltammetry and chronoamperometry at different temperatures, respectively. The results of the SEM and VSM analyses reveal that reduction of Dy3+ to Dy2+ may have occurred, while reduction of Dy3+ to Dy(0) is conjectured to play no role. Moreover, the results of chronoamperometry experiments show that nucleation in the alloy electrodeposition is instantaneous, and that, as the applied deposition potential becomes more negative, the nucleation density increases, which rapidly shortens the time required for the diffusion zones to overlap. Electrodeposition of a Dy-Co-Zn alloy on a Ni or Cu sheet from the 50-50 mol% ZnCl2-EMIC melt containing 1.687 mol% CoCl2 and 1.114 mol% DyCl3 has been accomplished, and the morphology and the composition have been analyzed by SEM and EDS, respectively. The magnetism of the deposited layer is discussed based on the results of the VSM analysis.

Time Required to Achieve Homogeneity of Test Substances Added to Dog Feed

1991 ◽  
Vol 74 (5) ◽  
pp. 857-861
Author(s):  
Philip P Sapienza ◽  
George J Ikeda ◽  
Patricia I Warr ◽  
Richard H Albert
Keyword(s):  
Nicotinic Acid ◽  
Animal Feed ◽  
Mixing Time ◽  
Critical Factor ◽  
Laboratory Animals ◽  
Time Period ◽  
Time Test ◽  
Time Required ◽  
Carrier Animal

Abstract The homogeneity of test substances in a carrier (animal feed) is a critical factor In conducting long-term feeding studies in laboratory animals. A method for determining the adequate amount of mixing to achieve homogeneity by a mixer of the type described has been determined when 2 distinctly different compounds are added to ground dog feed. Nicotinic acid and butylated hydroxyanlsole at a concentration of 1% were separately mixed with the dog feed for 15,30,45,60, and 120 min to determine optimum mixing time. Test portions were taken from 4 different sampling sites at each time period and analyzed in duplicate for the added substance. Four batches were prepared and the results were aggregated. Very little interbatch variability was observed. The variance of the average values from the 4 sampling sites at each time period was calculated and used as a simple, crude, but effective numerical quantity to monitor the approach to homogeneity of the mixture.

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