scholarly journals Suppression of Powdery Mildew on Greenhouse-Grown Cucumber by Addition of Silicon to Hydroponic Nutrient Solution Is Inhibited at High Temperature

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Andrew C. Schuerger ◽  
William Hammer
Keyword(s):  
Powdery Mildew ◽  
Light Intensity ◽  
Nutrient Solution ◽  
Potassium Silicate ◽  
Disease Suppression ◽  
Effect Of Temperature ◽  
Rooting Medium ◽  
Canadian Studies ◽  
The Difference ◽  
Nutrient Solutions

Silicon amendments to hydroponic nutrient solutions have been used successfully in Canada to suppress powdery mildew (PM) caused by Sphaerotheca fuliginea on cucumber (Cucumis sativus). In contrast, preliminary trials in Florida greenhouses failed to achieve the level of disease suppression reported in the literature for Canadian studies. A series of greenhouse experiments were conducted in Florida to determine the factors involved in reducing the effectiveness of silicon amendments for PM suppression on cucumber. Three horticultural practices (cultivar, nutrient solution formula, and rooting medium) and two environmental factors (light intensity and temperature) were tested in combination with silicon amendments for their effects on the suppression of PM on cucumber. When plants were irrigated with a standard nutrient solution amended with potassium silicate at 0 mg/liter, the cucumber cv. Vetomil was found to be resistant and cvs. Corona, Cilla, Farbio, and Toska were found to be susceptible to PM. Susceptible cultivars irrigated with potassium silicate at 100, 150, or 200 mg/liter exhibited a slight but statistically significant reduction in PM over the course of a 49-day trial. Although PM in the cultivar trial was slightly lower in treatments with added silicon, disease suppression with silicon was not commercially useful because it failed to increase fruit yields. Nutrient solution formula, rooting medium, and light intensity had no effects on the levels of PM suppression, regardless of whether plants were irrigated with potassium silicate at 0 or 100 mg/liter. Temperature was found to act in a synergistic manner with silicon. The greatest effect of temperature on PM suppression was observed at 20°C in which cucumber plants, irrigated with silicon at 100 mg/liter, exhibited significant reductions in the numbers of PM colonies per leaf. Disease suppression by silicon was observed at 25 and 30°C, but the magnitude of the disease suppression was significantly lower than when plants were maintained at 20°C. The effect of temperature on PM suppression by silicon may explain the difference in results between previous experiments in Canada, where greenhouse temperatures averaged 20 to 25°C, and the current study in Florida, where greenhouse temperatures averaged 24 to 32°C.

scholarly journals Foliar Applications of Potassium Silicate Reduce Severity of Powdery Mildew on Cucumber, Muskmelon, and Zucchini Squash

1992 ◽  
Vol 117 (6) ◽  
pp. 902-905 ◽  
Author(s):  
Jim Menzies ◽  
Pat Bowen ◽  
David Ehret ◽  
Anthony D.M. Glass
Keyword(s):  
Powdery Mildew ◽  
Active Ingredient ◽  
Potassium Silicate ◽  
Separate Experiment ◽  
Distilled Water ◽  
Sphaerotheca Fuliginea ◽  
Erysiphe Cichoracearum ◽  
Foliar Sprays ◽  
Application Methods ◽  
Nutrient Solutions

The effect of soluble potassium silicate applied to cucumber (Cucumis sativus L.), muskmelon (C. melo L.), and zucchini squash (Cucurbita pepo L.) on the severity of powdery mildew was examined. Application methods included amending nutrient solutions to a concentration of 1.7 mm Si and foliar sprays containing 1.7, 8.5, 17, and 34 mm Si. Untreated plants and plants sprayed with distilled water were used as controls. The leaves of all plants were inoculated with known concentrations of conidia of Sphaerotheca fuliginea (Schlecht.:Fr.) Poll. (cucumber and mu&melon) or Erysiphe cichoracearum DC.: Merat (zucchini squash) 1 day after the sprays were applied. Inoculated leaves on plants receiving the Si-amended nutrient solution or foliar sprays of ≥ 17.0 mm Si developed fewer powdery mildew colonies than those on control plants. Results of a separate experiment that included a potassium spray, indicated that the active ingredient of the potassium silicate sprays appears to be Si. Experiments to test the persistence of Si foliar sprays on cucumber demonstrated that a 17 mm Si spray applied 7 days before inoculation with S. fuliginea reduced mildew colony formation.

scholarly journals A Modified Nutrient Film Technique System Offers a More Uniform Nutrient Supply to Plants

2007 ◽  
Vol 17 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Alejandro R. Puerta ◽  
Suguru Sato ◽  
Yutaka Shinohara ◽  
Toru Maruo
Keyword(s):  
Plant Growth ◽  
Nutrient Solution ◽  
Vegetable Production ◽  
Fresh Weight ◽  
Uniform Size ◽  
Low Concentration ◽  
Nutrient Film Technique ◽  
The Difference ◽  
Nutrient Solutions ◽  
Fertilizer Solution

In nutrient film technique (NFT) vegetable production, the use of low-concentration nutrient solutions might lead to a nutrient concentration gradient along the bed, which can translate into nonuniform plant growth. The authors modified a conventional NFT system (cNFT) and propose a modified NFT (mNFT) that enables the production of lettuce (Lactuca sativa) plants of uniform fresh weight along elongated cultural beds. Two experiments were carried out to compare the systems when long cultural beds are used (18 m) in terms of uniformity of plant and nutrient solution characteristics. The results indicated that fresh weight of plants in cNFT decreased as the distance from the nutrient inlet increased, whereas no such trend was observed in mNFT. Leaf nitrate concentration in mNFT was uniform, whereas it was higher near the outlet of cNFT. Ascorbic acid concentration was also uniform in mNFT, but it was found to be lower near the outlet of cNFT. During Expt. 2, the oxygen content along the bed decreased from inlet to outlet in cNFT; however, in mNFT, it remained relatively constant at all sampling positions. Regarding the concentration of the nutrient solution along beds, no significant differences were found between inlet and outlet in both systems. It is suggested that the lower concentration of oxygen found at the outlet of cNFT might have reduced nutrient uptake, thus attenuating the difference in concentration between inlet and outlet. The temperatures of the nutrient solution along mNFT during Expt. 2 tended to be slightly lower than those of cNFT. However, temperatures were still too high and plant growth was negatively affected. The results of this study demonstrate that plants of uniform size and quality can be achieved in long cultural beds (up to 18 m long) supplied with a low-concentration fertilizer solution by using the proposed mNFT.

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 Variety resistance of winter barley to powdery mildew in the field in 1976−2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Winter Barley ◽  
Mildew Resistance ◽  
Average Resistance ◽  
The Difference ◽  
The Given ◽  
Resistance Of Varieties

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

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.

scholarly journals Comparison of root and foliar applications of potassium silicate in potentiating post-infection defences of melon against powdery mildew

2015 ◽  
Vol 64 (5) ◽  
pp. 1085-1093 ◽  
Author(s):  
L. J. Dallagnol ◽  
F. A. Rodrigues ◽  
S. F. Pascholati ◽  
A. A. Fortunato ◽  
L. E. A. Camargo
Keyword(s):  
Powdery Mildew ◽  
Post Infection ◽  
Potassium Silicate

scholarly journals Temperature and pH of the nutrient solution on wheat primary root growth

2004 ◽  
Vol 61 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Carlos Eduardo de Oliveira Camargo ◽  
Antonio Wilson Penteado Ferreira Filho ◽  
Marcus Vinicius Salomon
Keyword(s):  
Root Growth ◽  
Nutrient Solution ◽  
Primary Root ◽  
Growth Period ◽  
Triticum Aestivum L ◽  
Solution Temperature ◽  
Stages Of Development ◽  
Primary Root Growth ◽  
Temperature And Growth ◽  
Nutrient Solutions

Primary root growth is very important for wheat (Triticum aestivum L.) crop in upland conditions in the State of São Paulo. Fourteen wheat genotypes (mutant lines and cultivars) were evaluated for primary root growth during 7 and 15 days of development in complete and aerated nutrient solutions, in the laboratory. In the first experiment, solutions with three pH values (4.0, 5.0 and 6.0) at constant temperature (24 ± 1°C), and in the second experiment, solutions with the same pH (4.0) but with three temperatures (18°C ± 1°C, 24°C ± 1°C and 30°C ± 1°C) were used. High genetic variability was observed among the evaluated genotypes in relation to primary root growth in the first stages of development in nutrient solutions independent of pH, temperature and growth period. Genotypes 6 (BH-1146) and 13 (IAC-17), tolerant to Al3+ showed genetic potential for root growth in the first stages of development (7 and 15 days), regardless of nutrient solution temperature and pH. Genotypes 14 (IAC-24 M), 15 (IAC-24), 17 (MON"S" / ALD "S") ´ IAC-24 M2, 18 (MON"S" / ALD "S") ´ IAC-24 M3 and 24 (KAUZ"S" / IAC-24 M3), tolerant to Al3+, showed reduced root growth under the same conditions.

scholarly journals Four Types of LME Cracks in RSW of Zn-Coated AHSS

2020 ◽  
Vol 99 (3) ◽  
pp. 75s-92s ◽  
Author(s):  
SIVA PRASAD MURUGAN ◽  
◽  
YEONG-DO PARK ◽  
VIJEESH VIJAYAN ◽  
CHANGWOOK JI
Keyword(s):  
Tensile Stress ◽  
Synergetic Effect ◽  
High Strength Steels ◽  
High Strength ◽  
Liquid Zinc ◽  
Effect Of Temperature ◽  
Advanced High Strength Steels ◽  
Type D ◽  
The Difference

Zinc-coated advanced high-strength steels are known to be susceptible to liquid metal embrittlement (LME) cracking during resistance spot welding (RSW). Despite numerous reports with regard to LME during RSW, a systematic approach has not been proposed for the classification of cracks based on the cracking mechanism. The objective of this study was to characterize the LME cracks at various RSW locations, and thereby propose a classification method to identify the mechanism of the LME cracks at each location. The experimental results revealed the LME cracks were concentrated at certain weld locations and exhibited different features in terms of length, number, and orientation, owing to the synergetic effect of temperature, stress, microstructure, time of exposure to liquid zinc, and time of exposure to tensile stress at the corresponding lo-cations. Thus, the LME cracks were classified into four categories, namely type A, type B, type C, and type D, based on the formation location. The effect of time of exposure to liquid zinc and tensile stress on LME cracking revealed the time dependency of LME in RSW. The nature of contact be-tween the electrode and the sheet, and the heat input during welding, were found to be the main reasons for the difference in the thermal, mechanical, and metallurgical characteristics of various crack locations, which caused the formation of various LME crack types.

scholarly journals PENGARUH INTENSITAS CAHAYA TERHADAP KETERTARIKAN GEROMBOLAN IKAN PELAGIS KECIL PADA MINI PURSE SEINE DI PERAIRAN PEMALANG JAWA TENGAH

2017 ◽  
Vol 13 (2) ◽  
pp. 125
Author(s):  
Erfind Nurdin ◽  
Mohammad Natsir ◽  
Hufiadi Hufiadi
Keyword(s):  
Light Intensity ◽  
Significant Influence ◽  
High Intensity ◽  
Purse Seine ◽  
North Coast ◽  
Fish School ◽  
The Third ◽  
Small Intensity ◽  
The Difference ◽  
Fishing Practices

Penggunaan intensitas cahaya pada unit penangkapan light fishing cenderung meningkat. Hal ini, didasari atas persepsi bahwa intensitas cahaya yang tinggi akan meningkatkan hasil tangkapan. Fenomena ini dijadikan suatu penelitian yang dilakukan selama 3 minggu pada bulan September 2004 di perairan Pemalang Jawa Tengah. Alat tangkap pukat cincin mini (mini purse seine) di pantai utara Jawa pada operasi penangkapan selain menggunakan rumpon juga mengggunakan cahaya sebagai alat bantu penangkapan. Pengukuran nilai intensitas lampu dilakukan dengan meggunakan LI COR 250 quantum meter (μmol sɹ mɲ) pada jumlah lampu yang berbeda, dan digunakan pula akustik EY 500 untuk memperoleh data sebaran dan gerombolan ikan yang berada dalam pengaruh cahaya lampu. Pada deteksi awal (A) ikan cenderung mengelompok pada lahan intensitas tinggi, deteksi ke 2 (B) pengelompokkan mulai terkonsentrasi dekat kapal, deteksi ke-3 (C) pengelompokkan ikan bertambah banyak, dan deteksi ke-4 (D) kelompok ikan berada pada lahan yang sangat memungkinkan untuk ditangkap. Dari hasil penelitian diperoleh laju tangkap (catch rate) 125,7 kg per tawur. Perbedaan jumlah lampu yang sedikit tidak menunjukkan pengaruh yang terlalu besar terhadap hasil tangkapan. The influence of light intensity to the light fishing practices commonly tends to increase. Fishermen believe that with the higher intensity of light the bigger catch they have. This phenomenon stimulated us to a research that during was done three weeks on September 2004 in Pemalang West Java. Mini purse seine is conduct at north coast of Java use payaos and light artificial for fish attractive. LI COR 250 quantum metre (μmol sɹ mɲ) was used for light intencity at different lamps amount and EY 500 acoustic to obtain the data of fish school in influence of lamp light. At the first detecting (A) fish school was concentrated in high intensity area, the second detecting (B) the concentration was closer to the ship, the third detecting (C) fish school increased, and the forth detecting (D) fish school was consentrated in catchable area. The results show that the cath rate was 125.7 kg per setting. The difference of lamps amount with a small intensity did not show significant influence to the catch haul.

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