NITRIFICATION IN NUTRIENT SOLUTIONS WITH LOW LEVELS OF POTASSIUM

1959 ◽  
Vol 5 (5) ◽  
pp. 425-430 ◽  
Author(s):  
L. F. Welch ◽  
A. D. Scott
Keyword(s):  
Nutrient Solution ◽  
Room Temperature ◽  
Nitrifying Bacteria ◽  
Garden Soil ◽  
Soil Particles ◽  
High K ◽  
Low Levels ◽  
Low K ◽  
Nutrient Solutions ◽  
As If

An active culture of nitrifying bacteria was established by adding moist garden soil to a high-K nutrient solution and incubating the system at room temperature with adequate aeration. By a succession of transfers into a low-K nutrient solution the soil particles were eliminated and the K level reduced to 0.40 p.p.m. Inoculum from this soil-free, low-K nitrifying culture was then used to study nitrification in buffered nutrient solutions that contained even less K.When the nutrient solutions contained 0.40 p.p.m. K or more, there was no effect of the K level on the nitrification of NH4 added as (NH4)2SO4. Nitrification was impaired, however, when the K level was less than 0.35 p.p.m. In a solution that contained virtually no K there was negligible nitrification after a second transfer was made to eliminate the K added by the original inoculum. Under these conditions, the number of nitrifying bacteria apparently decreased, but some of them persisted for at least 48 days. Upon the addition of K, nitrification occurred to about the same extent as if ample K had always been present.

Effects of Ethacrynic Acid on Frog Gastric Mucosa in Chloride Solutions

1974 ◽  
Vol 52 (2) ◽  
pp. 166-173
Author(s):  
Mumtaz A. Dinno ◽  
Manuel Schwartz ◽  
Axel K. Olson ◽  
Gaspar Carrasquer
Keyword(s):  
Gastric Mucosa ◽  
Nutrient Solution ◽  
Ethacrynic Acid ◽  
Secretory Rate ◽  
High K ◽  
Solution Bathing ◽  
Transmembrane Potential Difference ◽  
Low K ◽  
Nutrient Solutions

The addition of ethacrynic acid to a concentration of 1 mM in the nutrient solution bathing the frog gastric mucosa in vitro produced an immediate decrease in resistance followed by an increase in resistance and a decrease in H+ secretory rate. The latter effect was irreversible and the former reversible. During the initial phase for nutrient solutions of 4 mM K+ and 79 mM K+ containing 1 mM ethacrynic acid, the decrease in resistance was about 30% and the decrease in the transmembrane potential difference (P.D.) was about 1 mV in the low K+ case and 2 mV in the high K+ case. The addition of ethacrynic acid to a 4 mM K+ nutrient solution containing 1 mM Ba2+ produced initially a 19% decrease in resistance and both positive and negative changes in P.D. In the absence of Ba2+, these results suggest strongly a marked increase of K+ permeability with the possibility of some increase of Cl− permeability. In the presence of Ba2+, as a result due to the increased K+ resistance of the nutrient membrane, ethacrynic acid may affect predominantly either K+ or Cl− permeability.

scholarly journals THE EFFECT OF ENVIRONMENTAL POTASSIUM AND CALCIUM CONCENTRATIONS ON THE RECOVERY OF THE ACTION POTENTIAL AND RELATED FUNCTIONS OF NERVE

1947 ◽  
Vol 30 (6) ◽  
pp. 493-517 ◽  
Author(s):  
Helen Tredway Graham ◽  
H. A. Blair
Keyword(s):  
Critical Level ◽  
Specific Effect ◽  
The Other ◽  
Level Control ◽  
Definite Effect ◽  
High K ◽  
Low Levels ◽  
K Concentration ◽  
Low K ◽  
Frog Sciatic Nerve

1. When the Ringer's solution applied to isolated frog sciatic nerve contains K+ in concentrations greater than 2 x standard, the height of the spike and of the after-potential is decreased, as is the duration of the after-potential; recovery of height and of excitability following response is delayed; degree and duration of supernormal excitability are decreased; postcathodal depression and postanodal enhancement are increased and prolonged. 2. The nerve functions just listed in general all change in the opposite direction when exposed' to increased environmental [Ca++]. (4.5–20 x standard) or decreased [K+] (0.05–0.2 x standard). The effects of decreased [Ca++] (0.20–0.25 x standard) are indeterminate. 3. When [K+] and [Ca++] are both greater than 2 x standard, whatever the ratio between the concentrations the effects characteristic of high [K+] eventually predominate. However, these effects, except for those involving spike height, are preceded by effects characteristic of high [Ca++] when this cation is present in sufficient excess. 4. When [K+] and [Ca++] are reduced to equal low levels (0.1–0.2 x standard), effects characteristic of low [K+] and high [Ca++] are obtained. 5. The experimentally determined order of ability of the environments to produce changes characteristic of high K+ (which is the reverse of the order of their ability to produce changes characteristic of high [Ca++]), is not the order of their K+ or Ca++ concentrations, nor of the ratio between these concentrations (Table II). 6. The results may be explained by the assumption that the functions investigated are all to greater or less degree controlled by (1) the [K+]/[Ca++] ratio and (2) the K+ concentration, at least when this exceeds a critical level. Control by [K+] is more effective for spike height and its recovery after stimulation than for the other functions. The special rôle of K+ is attributed to an unknown specific effect of this ion which Ca++ is unable to oppose. It is suggested that this K+ effect in general becomes marked on the frog nerve functions investigated when the K+ concentration is somewhat above 2 x standard, while the [K+]/[Ca++] ratio must be changed by a factor of 4 or more before it exerts a definite effect on these functions. 7. In standard and in modified cationic environments, nerve functions vary in the ease with which they manifest changes characteristic of high [K+] or of high [Ca++]. 8. The after-potential functions are less completely controlled by the cationic environment than are the other functions investigated.

scholarly journals Vitamin K distribution in rat tissues: dietary phylloquinone is a source of tissue menaquinone-4

1994 ◽  
Vol 72 (3) ◽  
pp. 415-425 ◽  
Author(s):  
H. H. W. Thijssen ◽  
M. J. Drittij-Reijnders
Keyword(s):  
Salivary Gland ◽  
Tissue Distribution ◽  
Vitamin K ◽  
Mitochondrial Fraction ◽  
Rat Tissues ◽  
High K ◽  
Low Levels ◽  
Low K ◽  
The Brain ◽  
Tissue Vitamin

The present study was undertaken to determine whether there is selective tissue distribution of vitamin K in the rat and whether this distribution mirrors the distribution of tissue vitamin K metabolism. The effects of feeding a vitamin K-free diet followed by resupplementation with phylloquinone (K1) were studied. K1was recovered in all tissues. In K1-supplemented rats, most tissues accumulated K1relative to plasma K1with the highest levels in liver, heart, bone, and cartilaginous tissue (sternum). Low K1levels were found in the brain. In the K1-free rats, relatively high K1levels were still found in heart, pancreas, bone and sternum. Surprisingly, menaquinone-4 (MK-4) was detected in all tissues, with low levels in plasma and liver, and much higher levels in pancreas, salivary gland and sternum. MK-4 levels exceeded K1levels in brain, pancreas, salivary gland and sternum. Supplementation with K1, orally and by intravenous infusion, caused MK-4 levels to rise. Some accumulation of K1and MK-4 in the mitochondrial fraction was found for kidney, pancreas and salivary gland. In the liver the higher menaquinones (MK-6–9) accumulated in the mitochondria. The results indicate that: (1) there is selective tissue distribution of K1and MK-4, (2) dietary K1is a source of MK-4. The results also suggest there may be an as yet unrecognized physiological function for vitamin K (MK-4).

Uptake and distribution of potassium by grapevine rootstocks and its implication for grape juice pH of scion varieties

1989 ◽  
Vol 29 (5) ◽  
pp. 707 ◽  
Author(s):  
EH Ruhl
Keyword(s):  
Nutrient Solution ◽  
Screening Method ◽  
Grape Juice ◽  
Low Ph ◽  
K Uptake ◽  
Plant Parts ◽  
High K ◽  
K Concentration ◽  
Positive Correlations ◽  
Low K

Differences in petiole K+ concentration of ungrafted grapevine rootstocks grown under field conditions at Merbein, Victoria, were compared with the rootstock effects on grape juice pH of the scion varieties Chardonnay and Ruby Cabernet. Significant positive correlations were obtained between grape juice pH of the scion varieties on various rootstocks and K+ accumulation in the petioles of ungrafted rootstock vines. Rootstock varieties that contributed to high pH in the grape juice of the scion (e.g. Freedom, Dog Ridge, Rupestris du Lot) showed high K+ concentrations in their petioles, while those rootstocks that contributed to low pH in the grape juice of the scion (e.g. 140 Ruggeri, 1202 Couderc, 110 Richter), had low K+ concentrations in their petioles. In 2 water culture experiments in the glasshouse, K+ uptake and distribution in ungrafted rootstock vines was examined at different K+ levels. In the first experiment the rootstocks 140 Ruggeri and Freedom had similar K+ concentrations in the various plant parts when grown in nutrient solution with 0.1 mmol K+/L. With K+ concentrations of 1, 2, and 10 mmol/L in the nutrient solution Freedom had significantly higher K+ contents in leaves and petioles than 140 Ruggeri. When K+ supply was increased from 1 to 2 mmol/L, K+ concentrations in the various plant parts were not significantly increased. However, when the supply was increased to 10 mmol/L, K t concentrations were significantly different. In the second experiment with K+ levels of 1 and 10 mmol/L, higher K+ contents were obtained in the basal and apical leaves of Dog Ridge and Ramsey compared with 140 Ruggeri, Schwarzmann, 1103 Paulsen and Sultana, while in roots, 140 Ruggeri, 110 Richter and Sultana had the highest K+ contents. Dog Ridge and Rarnsey are both known to increase scion grape juice K+ concentration and pH of the scion variety, while 140 Ruggeri and 1103 Paulsen contribute to low grape juice K+ concentration and pH. The results demonstrate that differences between rootstocks in the extent of K+ accumulation in the shoot are a major determinant of the rootstock effects on grape juice pH. The extent of K+ accumulation can best be measured in basal leaves or petioles. This provides a screening method for the evaluation of rootstocks which restrict K+ accumulation and contribute to lower grape juice pH.

Nitrate content in lettuce (Lactuca sativa L.) grown on aeroponics with different quantities of nitrogen in the nutrient solution

2002 ◽  
Vol 50 (4) ◽  
pp. 389-397 ◽  
Author(s):  
N. Kacjan-Maršić ◽  
J. Osvald
Keyword(s):  
Nutrient Solution ◽  
Lactuca Sativa ◽  
Nitrate Content ◽  
Fresh Weight ◽  
Primary Roots ◽  
The Mean ◽  
Low Levels ◽  
Shoot Weight ◽  
Ph Level ◽  
Nutrient Solutions

The influence of different quantities of nitrogen in the nutrient solution on growth, development and nitrate content was studied in aeroponically grown lettuce (Lactuca sativa L.). Three successive experiments were conducted in 1999 from April to September, in an aeroponic system. The lettuce plants, cv. Vanity, were grown in aeroponics using four different amounts of nitrogen in the nutrient solutions. The pH level was maintained between 5.5 and 6.5, and the EC between 1.8 and 2.2 mS/cm. Fresh weight measurements were made on all the material. The differences between the mean fresh shoot weights were statistically significant in all three experiments. In the first experiment, the maximum final fresh weight in the treatment with 8 mM nitrogen averaged 999.0 g. In the second and third experiments the largest amount of nitrogen, 12 mM NO3-N, significantly (p<0.05) increased the fresh shoot weight of lettuce plants. low levels of nitrate in the nutrient solution (4 mM NO3-N in the first and 1.2 mM NO3-N in the second aeroponic experiment) significantly (p<0.05) increased the fresh weight of the final roots compared with the level of nitrate in standard nutrient solution (12 mM NO3-N). The differences between the means for plant height were statistically significant (p<0.05) in all three experiments. In the first and third experiments the lengths of the primary roots of the lettuce plants were significantly (p<0.05) influenced by different NO3-N concentrations in the nutrient solution. The highest NO3- concentration in the lettuce leaves was recorded in plants grown in nutrient solutions with the highest NO3-N concentration (17 mM in the first, 12 mM in the second and third experiments). An acceptably low NO3- concentration was found in the leaves of lettuce treated containing with nutrient solution 4 mM NO3-N in all three experiments.

Electron Probe Analysis of Vertebrate Smooth Muscle: Distribution of Ca and Ci

1976 ◽  
Vol 34 ◽  
pp. 334-335 ◽  
Author(s):  
Avril V. Somlyo ◽  
H. Shuman ◽  
A.P. Somlyo
Keyword(s):  
Smooth Muscle ◽  
Electron Probe ◽  
Preliminary Report ◽  
Cell Damage ◽  
Electron Probe Analysis ◽  
Perinuclear Space ◽  
Probe Analysis ◽  
High K ◽  
Low K ◽  
Initial Results

This is a preliminary report of electron probe analysis of rabbit portal-anterior mesenteric vein (PAMV) smooth muscle cryosectioned without fixation or cryoprotection. The instrumentation and method of electron probe quantitation used (1) and our initial results with cardiac (2) and skeletal (3) muscle have been presented elsewhere.In preparations depolarized with high K (K2SO4) solution, significant calcium peaks were detected over the sarcoplasmic reticulum (Fig 1 and 2) and the continuous perinuclear space. In some of the fibers there were also significant (up to 200 mM/kg dry wt) calcium peaks over the mitochondria. However, in smooth muscle that was not depolarized, high mitochondrial Ca was found in fibers that also contained elevated Na and low K (Fig 3). Therefore, the possibility that these Ca-loaded mitochondria are indicative of cell damage remains to be ruled out.

NITROGEN NUTRITION OF CITRUS NURSERY STOCK IN PINE BARK SUBSTRATES.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1161f-1161
Author(s):  
John D. Lea-Cox ◽  
Irwin E. Smith
Keyword(s):  
Nutrient Solution ◽  
Nitrogen Nutrition ◽  
Dry Mass ◽  
Pine Bark ◽  
Growing Period ◽  
Rough Lemon ◽  
Nursery Stock ◽  
Citrus Rootstock ◽  
Cleopatra Mandarin ◽  
Nutrient Solutions

Pine bark is utilized as a substrate in citrus nurseries in South Africa. The Nitrogen (N) content of pine bark is inherently low, and due to the volubility of N, must be supplied on a continual basis to ensure optimum growth rates of young citrus nursery stock. Three citrus rootstock (rough lemon, carrizo citrange and cleopatra mandarin) showed no difference in stem diameter or total dry mass (TDM) when supplied N at concentrations between 25 and 200 mg ·l-1 N in the nutrient solution over a 12 month growing period. Free leaf arginine increased when N was supplied at 400 mg·l-1 N. The form of N affected the growth of rough lemon. High NH4-N:NO3-N (75:25) ratios decreased TDM when Sulfur (S) was absent from the nutrient solution, but not if S was present. Free arginine increased in leaves at high NH4-N (No S) ratios, but not at high NH4-N (S supplied) ratios. Free leaf arginine was correlated with free leaf ammonia. These results have important implications for reducing the concentration of N in nutrient solutions used in citrus nurseries and may indicate that higher NH4-N ratios can be used when adequate S is also supplied.

scholarly journals Silicon attenuates calcium deficiency by increasing ascorbic acid content, growth and quality of cabbage leaves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dalila Lopes da Silva ◽  
Renato de Mello Prado ◽  
Luis Felipe Lata Tenesaca ◽  
José Lucas Farias da Silva ◽  
Ben-Hur Mattiuz
Keyword(s):  
Ascorbic Acid ◽  
Nutrient Solution ◽  
Acid Content ◽  
Dry Matter ◽  
Ascorbic Acid Content ◽  
Calcium Deficiency ◽  
Ca Deficiency ◽  
Leaf Water Loss ◽  
Nutrient Solutions

AbstractCalcium (Ca) deficiency in cabbage plants induces oxidative damage, hampering growth and decreasing quality, however, it is hypothesized that silicon (Si) added to the nutrient solution may alleviate crop losses. Therefore, this study aims at evaluating whether silicon supplied in the nutrient solution reduces, in fact, the calcium deficiency effects on cabbage plants. In a greenhouse, cabbage plants were grown using nutrient solutions with Ca sufficiency and Ca deficiency (5 mM) without and with added silicon (2.5 mM), arranged as a 2 × 2 factorial in randomized blocks, with five replications. At 91 days after transplanting, the plants were harvested for biological evaluations. In the treatment without added Si, Ca deficiency promoted oxidative stress, low antioxidant content, decreased dry matter, and lower quality leaf. On the other hand, added Si attenuated Ca deficiency in cabbage by decreasing cell extravasation while increasing both ascorbic acid content and fresh and dry matter, providing firmer leaves due to diminished leaf water loss after harvesting. We highlighted the agronomic importance of Si added to the nutrient solution, especially in crops at risk of Ca deficiency.

High breakdown voltage AlGaN/GaN HEMT with high‐K/low‐K compound passivation

2015 ◽  
Vol 51 (1) ◽  
pp. 104-106 ◽  
Author(s):  
Jiangfeng Du ◽  
Nanting Chen ◽  
Peilin Pan ◽  
Zhiyuan Bai ◽  
Liang Li ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Gan Hemt ◽  
High Breakdown Voltage ◽  
High K ◽  
Low K
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