scholarly journals RESPONSE OF CATHARANTHUS ROSEUS “GRAPE COOLER” TO MEDIA AND FERTILIZER SOLUTION CONCENTRATION USING SUBIRRIGATION

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 687c-687
Author(s):  
G.C. Elliott ◽  
R.J. McAvoy ◽  
M. Abbott
Keyword(s):  
Electrical Conductivity ◽  
Catharanthus Roseus ◽  
Leaf Tissue ◽  
Solution Concentration ◽  
Essential Elements ◽  
Fresh Weight ◽  
The Third ◽  
Saturated Media ◽  
Final Harvest ◽  
Fertilizer Solution

Seedlings of Catharanthus roseus “Grape Cooler” was transplanted to cell packs of media: peat-vermiculite-perlite (MM220), peat-hydrophilic rockwool (ABS), and peat-hydrophobic rockwool (REP) and grown in subirrigation trays using 20N-4.4P-17K fertilizer at 50, 150 or 250 ppm N applied at each irrigation. Shoots of four plants in each of two replications were harvested 2, 3, 4 and 5 after transplant. Leaf samples from the third harvest were analyzed for essential elements. Electrical conductivity (EC) was measured in saturated media extracts at each harvest. Significant media by fertilizer interactions were obtained for fresh weight and leaf area at the final harvest. Greatest growth was obtained with 50 ppm N in ABS, but with 150 ppm N in MM 220 and REP. In tehse, growth was similar at 50 and 150 ppm N, but less growth REP than MM220 at 250 ppm. More growth was produced with ABS at 50 ppm N, but less at 150 or 250 ppm N. Leaf tissue N increased 38.5 to 54.5 mg g-1 dry wt. as fertilized increased 50 to 150 ppm, while other nutrients were not significantly affected. Media EC increased with time and fertilizer concentration, with EC in all media fertilized with 250 ppm N exceeding 4.5 dS m-1 at the final harvest.

scholarly journals 355 Effect of Season on Nitrate Accumulation in Hydroponic Lettuce

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 453D-453
Author(s):  
Martin P.N. Gent
Keyword(s):  
Nutrient Solution ◽  
Nitrate Concentration ◽  
Leaf Tissue ◽  
Solution Concentration ◽  
Mineral Elements ◽  
Essential Elements ◽  
High Concentration ◽  
Nitrate Accumulation ◽  
Nitrate Supply ◽  
N Treatment

Serial plantings of hydroponic lettuce were grown throughout the year in the northeast United States to determine how sunlight intensity and solution nitrate affect nitrate in leaf tissue. Two nutrient solutions were used. All essential elements were supplied at the same concentration, except nitric acid was added to the high-N treatment to increase nitrate to 5.7 mm (352 ppm), compared to 4.0 mm (248 ppm) in the low-N treatment. A feedback control system maintained a constant conductivity and volume in the recirculating nutrient solution. The actual nitrate concentration in solution was higher in winter than in summer. In winter, it rose to 800 ppm in the high-N solution, while it remained below 200 ppm in the low-N solution. In summer, nitrate was 200 to 400 ppm in the high-N solution, compared to 40 to 120 ppm in the low-N solution. Concentration of other mineral elements remained at levels similar to the original formulation. Nitrate concentration in leaf tissue when the lettuce plants reached a marketable size was sensitive to sunlight and nitrate supply. In spring and summer, tissue nitrate was as low as 1100 ppm. It increased to about 4000 ppm in lettuce grown in mid-winter in a shaded greenhouse and fed high-N solution, while low-N plants had less than 3000 ppm nitrate. Tissue nitrate was related to solution nitrate. Tissue nitrate increased in proportion to solution nitrate, up to about 400 ppm nitrate in solution, then leveled off at a concentration of about 4000 ppm in the leaves, a relation that was the same under all sunlight intensities. The accumulation of nitrate in the nutrient solution was one cause of the high concentration of nitrate in lettuce leaves.

Is Thermal and Light-Induced Annealing of Met Astable Defects in a-Si:H Driven by Electrons?

1995 ◽  
Vol 377 ◽  
Author(s):  
Helena Gleskova ◽  
S. Wagner
Keyword(s):  
Electrical Conductivity ◽  
Light Intensity ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Free Electrons ◽  
Free Electron Density ◽  
Independent Variables ◽  
The Third ◽  
Defect Annealing ◽  
Hydrogenated Amorphous

ABSTRACTWe report results of a search for a unifying rate law for the annealing of metastable defects in hydrogenated amorphous silicon (a-Si:H). We tested the hypothesis that defect-annealing by both heating or illumination is driven by the density of free electrons. This hypothesis is formulated via the rate equation - dN/dt = A nα N f (T), where N is the defect density, t the time, A a constant, n the free electron density, and f (T) a function of temperature derived from a distribution of annealing energies. The model fits two sets of data, with light-intensity and electrical conductivity as the independent variables, reasonably well, with a ranging from 0.39 to 0.76, but not the third set, where we varied the temperature.

scholarly journals The thermal and electrical conductivity of a single crystal of aluminium

1927 ◽  
Vol 115 (770) ◽  
pp. 236-241 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Single Crystals ◽  
Test Specimen ◽  
Average Diameter ◽  
National Physical Laboratory ◽  
Present Communication ◽  
Uniform Size ◽  
The Third ◽  
Physical Laboratory

The recent work of Carpenter and Elam on the growth of single crystals of large dimensions has rendered possible the study of the physical constants of single crystals of the commoner metals, and the present communication describes the determination of the thermal and electrical conductivity of aluminium in the form of an isolated crystal. The form of the crystal investigated is shown in fig. 1. This crystal had been prepared at the National Physical Laboratory employing the technique described by Carpenter in “Nature,” p. 266, August 21, 1926, which briefly is as follows:— The test specimen is machined and subjected to three treatments, thermal, mechanical, and thermal. The first treatment is necessary to soften the metal completely and produce new equiaxed crystals of so far as possible uniform size, the average diameter being 1/150 inch. The second consists in straining these crystals to the required amount, and the third in heating the strained crystals to the requisite temperature, so that the potentiality of growth conferred by strain could be brought fully into operation.

scholarly journals Effects of gibberellic acid and storage temperature on the germination of hawthorn seeds

2017 ◽  
Vol 63 (No. 9) ◽  
pp. 417-424 ◽  
Author(s):  
Ahmadloo Fatemeh ◽  
Kouchaksaraei Masoud Tabari ◽  
Goodarzi Gholam Reza ◽  
Salehi Azadeh
Keyword(s):  
Electrical Conductivity ◽  
Gibberellic Acid ◽  
Water Uptake ◽  
Temperature Regime ◽  
Storage Temperature ◽  
Fresh Weight ◽  
Freeze Thaw ◽  
Refrigerator Temperature ◽  
And Storage ◽  
Storage Temperatures

This study investigated methods to overcome seed dormancy in Crataegus pseudoheterophylla Pojarkova seeds. Seeds with and without endocarps were treated with gibberellic acid (GA<sub>3</sub>) at different concentrations and four storage temperatures. Then they were stratified in an alternate temperature regime. The amount of absorbed water in seeds with endocarps was monitored by measuring the fresh weight of seeds for 0, 24, 48, 72, and 96 h of imbibition. The electrical conductivity (EC) and the percentage of water uptake by seeds stored for 12 months at laboratory temperature, in a refrigerator, in a freezer, and in freeze-thaw conditions were measured. The highest germination (59.7%) was recorded in seeds without endocarps treated with 3,000 mg·l<sup>–1</sup> GA<sub>3 </sub>and stored either in a laboratory or a refrigerator (32.7–35.3%). All treatments of seeds without endocarps where GA<sub>3</sub> was applied showed statistically higher percentages of germination than the control. Seeds with endocarps stored at refrigerator temperature imbibed water up to 44.3% with increasing imbibition periods, whereas the amount of seeds that absorbed water in freezer and freeze-thaw conditions was almost the same. The tests showed the highest EC during storage in the freezer, with the lowest water uptake and viability in seeds stored during the freeze-thaw process.

Freedom from Development

2019 ◽  
Vol 12 (2) ◽  
pp. 323-349
Author(s):  
Michael Ilg
Keyword(s):  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Essential Elements ◽  
Social Citizenship ◽  
Wealth Creation ◽  
Role Of Government ◽  
The Third ◽  
Phases Of Development ◽  
Traditional Approaches

Abstract This paper proposes that there are three essential elements or phases of development: (i) systemic capacity; (ii) individual capability, and (iii) social citizenship. Significantly, the role of government within each element of development is decidedly different. Systemic capacity refers to the development of the economic means, or wealth creation, needed to provide society with services and public goods. Capability building refers to providing individuals with the basic conditions required to live a long and fulfilling life, such as health and education. Social citizenship recognizes that values held by individuals and groups will often conflict, and there is rarely a singular social end that can determine life in a free society. Fostering citizenship reflects the importance of belonging, and the obligations, responsibilities, and restraint that individuals owe to others, society, and the environment. This third element is a notable departure from many traditional approaches to development, which tend to concentrate on development as largely a process of feeding individual needs. The proposed approach is labelled “freedom from development,” for it is premised on the recognition that while society often benefits from the pursuit of traditional development, it does not do so exclusively nor without qualification. So while there are many instances in which development is a desirable social end, as when people derive greater capabilities from economic growth, there are also situations when the end of development must be displaced in favour of other social priorities. For example, there are times when markets yield freedom, and times when the freedom people crave will be found in rejecting the market altogether. Freedom from development suggests that values represented under the third element of citizenship will often have come at the expense of those of the first two elements, meaning that development in a traditional manner is superseded in a given context. In order to determine when freedom from development is socially desirable, it is suggested that a form of cost-benefit analysis is implicitly conducted, comparing the economic and individual gains available under the first two elements with the potential social gains from belonging under the third element of citizenship.

Evolution of enzyme activities during composting of tobacco waste

2011 ◽  
Vol 29 (11) ◽  
pp. 1124-1133 ◽  
Author(s):  
Hüseyin Hüsnü Kayikçioğlu ◽  
Nur Okur
Keyword(s):  
Electrical Conductivity ◽  
Alkaline Phosphatase ◽  
Enzyme Activities ◽  
Grape Pomace ◽  
Olive Pomace ◽  
Total N ◽  
Organic C ◽  
The Third ◽  
Tobacco Waste ◽  
Total Organic C

Main characteristics of tobacco waste generated during the processing of tobacco for cigarette manufacture are a high content of nicotine and total organic C. Composting is a way for decreasing the levels of nicotine and total organic C in tobacco waste and for disposal of this kind of agro-industrial waste. Changes in pH and electrical conductivity and activities of dehydrogenase, protease, alkaline phosphatase and β-glucosidase were determined during composting of tobacco waste (TW) and mixtures of TW + grape pomace (GP) and TW + olive pomace (OP). The nicotine in the tobacco waste was completely decomposed by composting. In the final composts, total organic C content and C : N ratio decreased, whereas the contents of total N, P and K increased. The pH of the composts increased rapidly at first and then more slowly and the electrical conductivity first decreased and then increased during composting. Mixing the tobacco waste with the other compost materials decreased the electrical conductivity level by 32 and 46% in the final TW + GP and TW + OP composts, respectively. The highest activities of the studied enzymes were observed on the third week of the composting process for dehydrogenase, the fifth week for protease and β-glucosidase and the ninth week for alkaline phosphatase. All enzyme activities stabilized about in 4 months.

scholarly journals Plant Growth and NOx-N in Leachate from Dieffenbachia maculata ‘Camille’

1994 ◽  
Vol 12 (3) ◽  
pp. 119-123
Author(s):  
C.A. Conover ◽  
L.N. Satterthwaite ◽  
R.T. Poole
Keyword(s):  
Electrical Conductivity ◽  
Plant Growth ◽  
Growth Parameters ◽  
Fresh Weight ◽  
N Content ◽  
Weight Growth ◽  
Leachate Characteristics

Abstract Dieffenbachia ‘Camille’ liners were planted and grown until “ready-for-market” in 1.6 liter pots containing Vergro Container Mix A without superphosphate. Plants were fertilized (FR) using 4, 8, 12, or 16 g 19N-2.6P-10K (0.14, 0.28, 0.42 or 0.56 oz 19–6–12) Osmocote 3-month release formula and were irrigated (IF) one, two or three times per week. Experiments were conducted during cooler months (20 weeks, January–May) and also during warmer months (13 weeks, June–September). Medium leachate samples were collected weekly for the duration of each experiment. Plant grade and top fresh weight (growth parameters) during the winter responded to an interaction between treatments (FR × IF). During the summer experiment, growth parameters were affected only by IF and were greatest at 3 irrigations per week. Weekly leachate characteristics (pH and electrical conductivity [EC], and P, NH4-N and NOx-N content) were affected only by FR, with increased fertilizer generally resulting in leachate with decreased pH and increased EC and increased P, NH4-N and NOx-N concentrations, in both winter and summer with the exceptions during the winter of P which increased with either an increase in FR or IF and of NOx-N which also increased with increased IF. Interaction occurred between FR and IF for total mg P leached during each experiment and for total mg NOx-N leached during the 20 week experiment, while total mg NOx-N leached during the 13 week experiment and total mg NH4-N leached in each experiment were affected only by FR.

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