Concentrations Of Calcium Nitrate Research Articles

Improving fruit set and quality of Daisy mandarin through foliar application of nutrients

Daisy mandarin is a widely cultivated citrus species valued for its nutritional qualities and organoleptic properties, favored for both fresh consumption and processing. Optimal growth and fruit production is depend upon the availability of essential nutrients. However, soils of the central zones of Punjab are deficient in potassium which hinders the quality and production and their deficiency impairs physiological and biochemical processes, reducing fruit set, yield and quality. Potassium and calcium are vital for metabolic functions and cell wall integrity. A deficiency in any of these nutrients can results in smaller fruits, lower fruit retention and diminished organoleptic and nutritional qualities, such as reduced antioxidants content. So that, a research was conducted to evaluate the effect of different concentrations of potassium nitrate, potassium sulfate, calcium nitrate and boric acid along with paddy straw mulching on Daisy mandarin during the years 2021–22. The pooled data of this research showed that potassium nitrate (2%), is the best treatment with maximum fruit set (14.37%) and retention (72.35%) in Daisy mandarin. Additionally, the average fruit weight (207.50 g), number of fruits (162), fruit yield (33.79 kg/tree), fruit length (6.25 cm) and breadth (6.73 cm) also enhanced. Furthermore, potassium nitrate (2%) application increased the antioxidant activity (39.43%), phenolic content (230.00 mg kg−1 FW) and flavonoid content (3.69 mg RE g−1 FW). The findings suggest that application of potassium nitrate presents a promising strategy for enhancing fruit set, yield and quality of Daisy mandarin, providing valuable insights for improved cultivation practices.

Trocas gasosas e produção em couve folha sob concentrações de Ca(NO3)2 em solução nutritiva salinizada

ABSTRACT Adequate mineral supplementation can be a strategy to enable the use of brackish water in the production of vegetables. This study intended to evaluate the effect of calcium nitrate concentrations on leaf gas exchanges and yield of kale (Brassica oleracea L) fertigated with salinized nutrient solutions. The experiment was conducted in a randomized block experimental design (4 + 1), with four replicates. Four nutrient solutions prepared in brackish water (6.0 dS m-1) containing four concentrations of Ca(NO3)2 [(750, 1,125, 1,500, and 1,875 mg L-1)] and a control treatment (standard nutrient solution using low-salinity water, 0.5 dS m-1 (750 mg L-1 of Ca(NO3)2) were used in the study. The following analyses were performed: leaf gas exchanges, leaf area, and fresh matter yield. The standard nutrient solution promoted higher values for photosynthetic rate (13.06 µmol CO2 m-2 s-1), stomatal conductance (0.19 mol H2O m-2 s-1), transpiration (2.76 mmol H2O m-2 s-1), instantaneous water use efficiency (4.73 mmol CO2 mol-1 H2O), instantaneous carboxylation efficiency (0.053 mmol CO2 mol-1 CO2), leaf area (2.78 cm2 per plant), and leaf fresh matter yield (2.64 kg per plant). The Ca(NO3)2 not nullified but mitigated the deleterious effect of salt stress on leaf gas exchanges, except for kale yield (leaf fresh matter).

Pre-harvest Application of Calcium Maintained Fruit Quality in Cold Stored Plum

: An experiment was conducted to study the influence of pre-harvest applications of different concentrations of calcium nitrate on various physico-chemical parameters of plum ( L.) Satluj Purple under cold storage conditions. Uniform and healthy plants Prunus salicina cv. of plum Satluj Purple were sprayed with calcium nitrate (1.0, 1.5 and 2.0 %) in 2 and 3 week of April and control plants were water sprayed cv. nd rd only. Fruits from both treated and control plants were harvested at colour break stage, and then stored at low temperature conditions (0–1 °C and 90–95 % RH) for 35 days. Evaluation of different physico-chemical parameters were made on 0 day and after 7, 14, 21, 28 and 35 days of storage. The results revealed that two sprays of Ca(NO ) @ 2.0 % retained maximum pulp: stone (15.37), total soluble solids (12.93 %), 3 2 titratable acidity (0.69 %), reducing (6.52 %) & non-reducing sugars (2.64 %) and total phenolics content (101.19 mg 100g ) at the end of -1storage. The fruits treated with two sprays of Ca(NO ) @ 2.0 % were effective in maintaining the quality of fruits without any spoilage up to 35 3 2 days under low temperature storage conditions.

Definition of a growth medium to evaluate pollen viability in Hemerocallis cultivars

Hemerocallis is a floriferous species, which presents numerous genotypes that are constantly crossed, generating new cultivars. The germination and viability of pollen are influenced both by factors that are intrinsic and extrinsic to the pollen. In view of the above, the purpose of this study was to establish a growth medium for the germination of pollen grains. Cultivar Morgana was used in the experiments performed to establish the growth medium, in which four pH ranges were tested alongside four agar concentrations. For the next test, five sucrose concentrations were tested. Afterwards, four boric acid concentrations were added to the medium, finally followed by four calcium nitrate concentrations. After the definition of the growth medium, the incubation time for pollen grains germination of the species was evaluated. The results were then applied to four cultivars in order to verify the respective germination percentages. It was noted that the highest percentage of in vitro germination occurred with the concentrations of 4 g L−1 agar, 74.6 g L−1 sucrose, 800 mg L−1 boric acid and 590 mg L−1 calcium nitrate, with a pH of 5.74 and ideal incubation time of 3 h. Regina being to cultivar with the highest germination percentage.

Control of Anthracnose Caused by Colletotrichum Gloeosporioides in Calcium Nitrate Foliar-Sprayed Dioscorea Alata Variety Agbodo

This study investigated the effect of calcium nitrate foliar spray on Anthracnose disease caused by Colletotrichum gloeosporioides Penz in the Nigerian water yam Dioscorea alata variety Agbodo. The field experiment was a randomized complete block design (RCBD) with three replications. Calcium nitrate at the rates 0mgl-1 (control), 5mgl-1 and 10mgl-1 were sprayed on the plants at 12 weeks after planting (12 WAP). No surfactant was added to the nutrient spray. Disease incidence in the contral was 54.44% and 65.00% at 20 WAP and 24 WAP significantly higher than the two calcium nitrate treatments which had overall mean of 47.23% and 48.06% at 20 WAP and 24 WAP respectively. Anthracnose disease severity score (DSS) which was similar across treatments at 20 WAP was at resistant level, overall mean score of 1.38. DSS was also similar across treatments at 24WAP but had moved up to moderately resistant category with overall mean of 1.69. Previous reports of calcium nitrate foliar spray for anthracnose control in Dioscerea species were with concentrations of 100mgl-1 up to 12000mgl-1 and with addition of Polysorbate 20 as surfactant in the liquid. Further trials with calcium nitrate concentrations similar or lower than that used in this study without surfactant and sprayed twice at 12WAP and 20WAP, and severity assessed at 20WAP, 24WAP and 32WAP is suggested for reduction of severity to resistant level in water yam variety Agbodo and other Nigerian water yam varieties. Total phenolic compounds (TPC) content of variety Agbodo leaves at 24WAP was 3.85mg GAE/g dm in the 10mgl-1 treatment, significantly higher than the 5mgl-1 treatment content of 3.33mg GAE/g dm, which was in turn higher than control TPC content of 2.93mg GAE/g dm. Phenolic compounds in leaves of water yam have been reported to be responsible for resistance to anthracnose, therefore calcium nitrate foliar spray concentrations similar or lower than that in this study are recommended for trials to reduce severity to resistant level in water yam Agbodo and other water yam  varieties. Leaf calcium, nitrogen, phosphorus, potassium and sulphur all increased from the 5mgl-1 treatment to the 10mgl-1 treatment (as with TPC), and also were significantly higher than the control. The overall means were 9.35mg/100g dm for Ca, 0.775% for N, 34.37mg/100g dm for P, 196.05mg/100g dm for K and 1.59% for S. Leaf magnesium (Mg) was similar across treatments with overall mean of 17.13mg/100g dm. Increased calcium will favour resistance to anthracnose because of calcium role in membrane function and stability and cell wall integrity. Increased leaf N in relation to disease resistance is reported to be pathogen-specific and will increase resistance especially for facultative parasites such as Colletotrichum gloeosporioides. This is because increase in nitrogen supports metabolic activities of host cells which favour obligate parasites but will not favour facultative parasites as the latter are semi-saprophytes which prefer senescing plant tissue or alternatively produce, toxins to kill host plant cells.

Calcium nitrate on growth and ornamental traits at salt-stressed condition in ornamental kale (Brassica oleracea L. var. Acephala)

Abstract Ornamental plants are used to improve the aestheticquality of urban and rural landscapes, recreational areas, interiorscapes and commercial sites. Any negative effects of salts on ornamental plant growth have to be taken into consideration mainly for their negative influences on aesthetic value of ornamental plants. The research was conducted to determine the effects of different concentrations of calcium nitrate on some stress parameters (i.e. leaf relative water content, chlorophyll, stomatal conductance, ion leakage in the leaf tissues) and some plant growth parameters (total leaf number, number of dried leaf, main stem diameter, plant crown diameter, plant height, fresh and dry weight of root) of ornamental kale (Brassica oleracea L. var. acephala) plant grown under saline conditions. Four doses of NaCl (NaCl1:30, NaCl2:60, NaCl3:90, NaCl4:120 mM), three doses of Ca(NO3)2 (CaN1:5, CaN2:10, CaN3:15 mM), groups combined together in all doses of NaCl and Ca (NO3)2 and control (NaCl0:0 + CaN0:0) were applied into the pots with three replications. Ca (NO3)2 was applied to the leaf surface of the plants in the pots to be applied as Ca (NO3)2 spray. When the plants reached a certain maturity (two weeks after transfer to the pot), salt stress applications were started. Ca (NO3)2 treatments have applied after one week from salt stress applications. Calcium nitrate treatements applied under salt stress conditions had positive effects and increasing in effect on all parameters examined except for chlorophyll and ion leakage in leaf tissues of the plant. With increasing in calcium nitrate concentration, morphological and physiological characteristics of plants were observed increases in general. It was concluded that the increase of the number of leaves by NaCl2+CaN3 application can be minimized with CaN3 (with 15 mM Ca (NO3)2) stress caused by 60 mM salt concentration According to the results of the research, calcium nitrate applications can be recommended for ornamental kale plants grown under salt stress conditions especially limiting the negative effects of stress and to minimize such damage.

Collection time, dehidration, culture media and environment for germination and storage of campomanesia guazumifolia (cambess.) O. Berg. Pollen

Abstract Sete-capote tree, a neglected species, has great ecological, cultural and potential economic importance, however, studies for this and other native species of the Myrtaceae family are still scarce. The objective of this study was to elucidate aspects of pollen germination and viability of this specie. For the experiment, pollen from flowers in pre and post anthesis was used, which was dehydrated in a chamber containing silica, for different periods. For germination tests, different concentrations of sucrose, boric acid and calcium nitrate were used. After obtaining germination results above 80%, the pollen grains were stored in refrigerator (5 °C), freezer (-17 °C), liquid nitrogen (-147 °C) and natural environment (± 25 °C), evaluating monthly the germination, until total loss of viability. For germination, it was recommend using pollen from flowers in post-anthesis, dehydrated for 24 hours in a silica chamber. The culture medium should contain 12% sucrose (C12H22O11), 10% boric acid (H3BO3) and 20% calcium nitrate (Ca(NO3)2) to obtain high germinative percentages. In addition, pollen presents orthodox behavior and when stored in liquid nitrogen, remains viable for 30 days.

Sprouting, phenology, and maturation of the Italian grapevine ‘Fiano’ in Campo Largo, PR, Brazil

Despite the expansion of viticulture in Brazil, the lack of chilling hours is a factor that requires the use of growth inducers to promote sprouting. Erger™ is a product of low toxicity and efficient in the bud induction of apple. However, there is a lack of studies testing such a product on the grapevine. This research was carried out to evaluate the sprouting and phenological cycle of ‘Fiano’ grapevine after Erger™ and calcium nitrate application in comparison to hydrogen cyanamide, as well as characterizing its production in Brazil. The experiment was carried out in Campo Largo, PR, under a trellis system, with plants spaced at 1.25 × 2.7 meters. The experimental design was a randomized complete block design with four replications and three plants per plot. Different concentrations of Erger™ and calcium nitrate (3%, 5%, 7%, and control) were tested compared to the standard dose of Dormex™ (4%) to induce sprouting in ‘Fiano’ grapevine, while phenological aspects of this cultivar were evaluated following the BBCH scale. Soluble solids content, titratable acidity, and pH were evaluated weekly after the beginning of berry maturation. The main biometric and qualitative characteristics of bunches were evaluated at harvest. All treatments presented satisfactory sprouting rates in 2014, but a lower cold accumulation was observed in 2015, and Erger™ application significantly increased sprouting when compared to the control. Plants treated with Erger™ had a delay in sprouting in the two years of study, requiring more time to reach a satisfactory percentage of open buds. The anticipation of sprouting was also observed in all treatments in the second agricultural season due to higher temperatures in relation to the previous year when the occurrence of low temperatures led to a longer time to start bud opening, which was related to ecodormancy. The cultivar Fiano is productive and adapted to the conditions of Campo Largo, PR, Brazil.

Growth, Pigment and Protein Production of Spirulina platensis under different Ca(NO3)2 concentrations

Spirulina platensis is a filamentous cyanobacterium that has been commerically used for fish feed and human food supplement. Low-cost production of Spirulina is needed when considering large-scale culture especially for industrial purposes. The aim of this study was to explain the effect of calcium nitrate (Ca(NO3)2) on growth, biomass, pigment, and protein production of S. platensis and to determine the best calcium nitrate concentration for Spirulina production.The microalgae was cultured at four calcium nitrate concentrations (1, 1.5, 2.0 and 2.5 g/L) with salinity of 15 ppt, constant light intensity of 4,000 lux and photoperiod of 24:0 light:dark cycles for 4 days. The results showed that different calcium nitrate concentrations remarkably affected the growth, biomass production, pigment and protein content of S. platensis (p<0.05). The highest specific growth rate of 0.721 day-1 and biomass concentration of 1.512 g/Lwere achieved at calcium nitrate concentration of 2.5 g/L. Moreover, the algae had the highest chlorophyll-a, carotenoid and protein content at 2.5 g L-1. Increasing calcium nitrate concentration from 1 to 2.5 g/L led to an increase in biomass, pigment and protein production of S. platensis. However, there was no significant difference between 2 and 2.5 g L-1 calcium nitrate concentrations. We suggest that 2-2.5 g/L Ca(NO3)2 concentration can be used profitably for S. platensis production.

Effect of Electron Acceptor on Hydrocarbon Pollution Degradation Rate Caused by Bacteria of the Genus Rhodococcus under Anaerobic Conditions

The effect of the concentration of an oxygen acceptor in the form of a nitrate-containing salt on the rate and mechanism of hydrocarbon degradation (HC) in actual soil samples extracted from wells of 1 to 5 m in depth from areas allocated for future urban development under the influence of bacterial strains belonging to the genus Rhodococcus (R. ruber Ac-1513 D and R. erythropolis Ac-1514 D) is studied. Initial soil samples containing up to 9.8% HC were capable of producing biogas for 59 years under anaerobic conditions, in the absence of an oxygen acceptor, under the influence of methane-forming indigenous microorganisms. At the same time, the content of fire-dangerous methane in gas products ranged from 8 to 36%, which makes housing development in such areas unacceptable without preliminary treatment. To accelerate hydrocarbon degradation by oil-oxidizing bacteria under non-specific oxygen-free conditions, it was proposed to use an electron acceptor, calcium nitrate. The mechanism of hydrocarbon degradation in the presence of Ca(NO3)2 through denitrification has been established. It is shown that effect of calcium nitrate studied in the presence of three concentrations (1.25, 2.5, and 5.0%) on denitrification and anaerobic HC degradation was reversely proportional, which may be associated with the inhibition of the denitrification process by high concentrations of Ca(NO3)2. In the presence of a minimum concentration of calcium nitrate (1.25%), maximum rates of anaerobic HC degradation in the soil are of k = 1.27 and 0.32 year–1 during warm and cold seasons, respectively. The content of the main non-flammable reaction product, carbon dioxide in the gas mixture was 99% by volume. Thus, the complete decomposition of the hydrocarbon and the gas generation phase may be completed within 1 year, which is 59 times faster than processes occurring in the absence of an oxygen acceptor.

Early Root Transcriptomic Changes in Wheat Seedlings Colonized by Trichoderma harzianum Under Different Inorganic Nitrogen Supplies.

Wheat is one of the most important crops worldwide. The use of plant growth promoting microorganisms, such as those of the genus Trichoderma, constitutes an alternative to chemical fertilizers, since they are cheaper and are not detrimental to the environment. However, the interaction between Trichoderma and wheat plants has been scarcely studied, at least at a molecular level. In the present work, a microarray approach was used to study the early transcriptomic changes induced in wheat roots by Trichoderma harzianum, applied alone or in combination with different concentrations of calcium nitrate [Ca(NO3)2], which was last used as nitrogen (N) source. Our results show that T. harzianum causes larger transcriptomic changes than Ca(NO3)2 in wheat roots, and such changes are different when plants are challenged with Trichoderma alone or treated with a combination of T. harzianum and Ca(NO3)2. Overall, T. harzianum activates the expression of defense-related genes at early stages of the interaction with the roots, while this fungus reduces the expression of genes related to plant growth and development. Moreover, the current study in wheat roots, subjected to the different T. harzianum and Ca(NO3)2 combinations, reveals that the number of transcriptomic changes was higher when compared against those caused by the different Ca(NO3)2 concentrations than when it was compared against those caused by T. harzianum. N metabolism gene expression changes were in agreement with the levels of nitrate reductase activity measured in plants from Trichoderma plus Ca(NO3)2 conditions. Results were also concordant with plant phenotypes, which showed reduced growth at early interaction stages when inoculated with T. harzianum or with its combination with Ca(NO3)2 at the lowest dosage. These results were in a good agreement with the recognized role of Trichoderma as an inducer of plant defense.

Micropropagation of Banana: Reversion, Rooting, and Acclimatization of Hyperhydric Shoots

Hyperhydricity is a physiological disorder impacting plant growth and multiplication and acclimatization of regenerated plantlets. We report the use of calcium nitrate for reversion and acclimatization of banana ‘Grand Naine’ hyperhydric shoots cultured on Murashige and Skoog medium containing agar or gellan. Although 100% rooting of hyperhydric shoots occurred at all concentrations of calcium nitrate, only 50% rooting was recorded in the absence of calcium nitrate. Electrolyte leakage decreased significantly in the reverted banana tissues compared with the hyperhydric tissues. Histochemical staining for reactive oxygen species indicated that reverted banana tissues possess lower levels of both hydrogen peroxide (H2O2) and superoxide (O2-) than do hyperhydric tissues. Rooting, growth, and survival of the reverted banana plantlets were significantly influenced by calcium nitrate concentrations as well as the type of gelling agent. Reverted banana plantlets in medium containing calcium nitrate (0.5–1 g·L−1) were acclimatized with 100% survival in a growing substrate of peatmoss and vermiculite (1:1).

Postharvest Quality of Roses under Different Levels of Nitrogenous Compounds in Holding Solution

Abstract Nitrogen (N) forms and N levels can have a great impact on growth and quality of agricultural crops. Postharvest N treatments may also affect the quality of products. This study was conducted under laboratory conditions to evaluate the changes in postharvest quality characteristics of cut roses (Rosa hybrid cv ‘Utopia’) under different nitrogen concentrations of holding solution. Three nitrogen sources including ammonium sulfate, calcium nitrate and potassium nitrate at five concentrations (0, 5, 10, 15 and 20 mgL-1 N) were applied into vases with holding solution. The results showed that low ammonium (5 mg L-1) and high nitrate (20 mgL-1) resulted in the highest leaf SPAD values, whereas the lowest values were recorded for those stems treated with the two highest ammonium concentrations (15 and 20 mg L-1). Leaf and petal relative water contents (RWC) were significantly reduced by higher ammonium concentrations, while they were increased by increasing calcium nitrate and potassium nitrate concentrations in the vase holding solution. Leaf catalase activity was increased by the two lowest (5 and 10 mg L-1) and decreased by the two highest ammonium levels (15 and 20 mg L-1), and it was not affected by the two other nitrogen salts. Higher ammonium levels resulted in a significant increase in leaf proline concentrations and petal ion leakage, whereas nitrate concentrations reduced these two traits. A low concentration of ammonium (5 mg L- 1) increased flower vase life while higher ammonium concentrations reduced the trait. There was also an increasing trend in flower vase life with higher concentrations of both nitrate salts. Therefore, low ammonium or high nitrate levels in vase holding solution can improve vase life quality of cut roses.

Effects of Ionic Strength, Salt, and pH on Aggregation of Boehmite Nanocrystals: Tumbler Small-Angle Neutron and X-ray Scattering and Imaging Analysis

The US government currently spends significant resources managing the legacies of the Cold War, including 300 million liters of highly radioactive wastes stored in hundreds of tanks at the Hanford (WA) and Savannah River (SC) sites. The materials in these tanks consist of highly radioactive slurries and sludges at very high pH and salt concentrations. The solid particles primarily consist of aluminum hydroxides and oxyhydroxides (gibbsite and boehmite), although many other materials are present. These form complex aggregates that dramatically affect the rheology of the solutions and, therefore, efforts to recover and treat these wastes. In this paper, we have used a combination of transmission and cryo-transmission electron microscopy, dynamic light scattering, and X-ray and neutron small and ultrasmall-angle scattering to study the aggregation of synthetic nanoboehmite particles at pH 9 (approximately the point of zero charge) and 12, and sodium nitrate and calcium nitrate concentrations up to 1 m. Although the initial particles form individual rhombohedral platelets, once placed in solution they quickly form well-bonded stacks, primary aggregates, up to ∼1500 Å long. These are more prevalent at pH = 12. Addition of calcium nitrate or sodium nitrate has a similar effect as lowering pH, but approximately 100 times less calcium than sodium is needed to observe this effect. These aggregates have fractal dimension between 2.5 and 2.6 that are relatively unaffected by salt concentration for calcium nitrate at high pH. Larger aggregates (>∼4000 Å) are also formed, but their size distributions are discrete rather than continuous. The fractal dimensions of these aggregates are strongly pH-dependent, but only become dependent on solute at high concentrations.

Supplemental calcium nitrate mitigates NaCl-induced biochemical, physiological, and antioxidant changes in sesame

ABSTRACTSodic soils reduce growth and production of most vegetables, including sesame (Sesamum indicum L.), and NaCl interferes with the nutrient balance of the rhizosphere. A greenhouse experiment was undertaken to investigate the effects of calcium nitrate fertigation and NaCl concentration on growth and development of sesame. The NaCl concentrations applied in the irrigation water were 0, 30, 70, or 100 mM, and the calcium nitrate levels were 0 or 100 mg·L−1. Leaf area and shoot dry weight did not change with addition of calcium nitrate (100 mg∙L−1) at all NaCl levels. At 100 mM, plants supplemented with 100 mg∙L−1 calcium nitrate produced 51% and 136% more chlorophyll (a) and carotenoids, respectively, and enhanced proline content by 45% and total soluble proteins by 25%. Calcium nitrate supplemented plants accumulated more Na+ ions at roots (+26%) and less Na+ ions at leaves (−20%). These plants generally had higher K+ content at roots (+30%) and at leaves (+94%) owing to 100 mM NaCl. Calcium nitrate (100 mg·L−1) enhanced catalase activity (+43%) and phenolic compounds. Calcium nitrate supplemented plants (100 mg∙L−1) accumulated less malondialdehyde (−50%) and had the highest antioxidant activity compared to 0 mg·L−1. Calcium nitrate may be used to moderate some adverse physiological effects of NaCl for sesame in sodic soils. However, the calcium nitrate concentration was not sufficiently high to benefit yield.

Ameliorative effects of calcium nitrate and humic acid on the growth, yield component and biochemical attribute of pepper ( Capsicum annuum ) plants grown under salt stress

The present work was carried out in order to determine the effects of calcium nitrate and humic acid applications either separately or in combination on the growth and fruit yield quality of pepper plants under salt stress condition. Two different concentrations of calcium nitrate (Ca1; 60 mg/kg soil and Ca2; 120 mg/kg soil) were applied to the soil before sowing whereas humic acid applications (HA1; 750 mg/kg soil and HA2; 1500 mg/kg soil) were performed during plant growth (at the third true leaves stage). Plants were irrigated with saline water in a concentration of 100 mM NaCl. Data showed that applications of both concentrations of humic acid and lower concentration of calcium nitrate (Ca1) individually caused significant increases in growth parameters, RWC, photosynthetic pigments, minerals content, non-enzymatic antioxidants contents of the plants under normal and salt stress conditions. Moreover, fruit antioxidant compounds and quality of fruits (capsaicin, lycopene, β-carotene, total phenol, total flavonoids and antioxidant activity) were improved by using theses treatments. The combined treatment of Ca1 and HA2 was the most effective one on the previous criteria under salt stress conditions. Therefore, the usage of humic acid and calcium could be suggested to improve the soil properties, growth and antioxidant capacity of pepper plants and to mitigate the damage caused by salt stress.

Preparation and Characterization of Precipitated Nano Hydroxyapatite

Calcium Hydroxyapatite [Ca10(PO4)6(OH)2] is the main inorganic constituent of human rigid tissues. It constitentes the major component of bone and enamel. In our present work, hydroxyapatite was synthesized by chemical co- precipitation method with the addition of different concentrations of calcium nitrate tetra hydrate [Ca(NO3)2.4H2O] and phosphoric acid [H3PO4] using micro wave irradiation. Experiments were conducted under controlled environment maintaining required pH, concentration of solution and temperature. The Present report emphasises on the synthesis and characterization of the nano hydroxyapatite. The result of Fourier Transform Infrared Spectroscopy [FTIR] showed the existence of the functional group present in hydroxyapatite. Scanning Electron Microscope [SEM] explains the surface morphology, size and dimensions of hydroxyl apatite. Thermo Gravimetric Analysis and Differential Thermal Analysis [TGA/DTA] analysis confirms that the high thermal stability of hydroxyapatite is due to the variation in concentration and its hardness is maximum.

Impact of Nitrogen Source and a pH Buffer on the in vitro Growth and Morphology of Rhizoctonia solani AG 2‐2 LP

Large patch (LP) disease of zoysiagrass (Zoysia japonica Steud.) caused by the fungal pathogen Rhizoctonia solani AG 2‐2 LP is an important disease in the United States transition zone that limits the utility and aesthetics of lawns and golf fairways. A preliminary study has shown that R. solani grown on ammonium‐based media remained white, while isolates grown on nitrate‐based media and potato dextrose agar (PDA) were melanized and brown. This study aimed to evaluate the effects of nitrogen source and a pH buffer on the radial growth and morphology of R. solani AG 2‐2 LP. Forty isolates were initially grown on antibiotic amended PDA and transferred to water agar. Mycelial plugs from water agar were transferred to basal media amended with ammonium sulfate (AMS), calcium nitrate, or urea at concentrations of 0, 50, 100, 200, 400, and 800 µg mL−1. A second set of each concentration was also amended with fumaric acid (FA) pH buffer. All media was brought to pH of 7.0 prior to autoclaving. Radial growth was recorded after 4 d. Isolates grown on calcium nitrate had the greatest radial growth, isolates grown on AMS were intermediate, and urea‐grown isolates had the least radial growth (P < 0.0001). Radial R. solani colony growth increased with increasing calcium nitrate concentration, but growth decreased with increasing AMS and urea concentrations. Fumaric acid increased radial growth on all N‐sources. All isolates melanized on media amended with calcium nitrate and urea. Isolates grown on 200 µg mL−1 AMS melanized with FA, but remained white without FA. If melanin plays a role in pathogen infection and pathogen survival, a fertility program involving AMS may be useful in an integrated strategy to suppress large patch.

Performance of modified self-healing concrete with calcium nitrate microencapsulation

This study investigates the strength reduction associated with incorporating calcium nitrate microcapsules in concrete. It also proposes modifications to the calcium nitrate micro encapsulation procedure to minimize the concrete strength reduction. These modifications consist of altering the continuous phase composition and keeping that of the aqueous phase the same. Amounts of 1%–10% of low Hydrophilic-Lipophilic Balance (HLB) emulsifier and 0.1%–1.0% of oil-soluble sulfonic acid catalyst (by weight of water in the aqueous phase) were dissolved in an organic solvent to prepare the continuous phase. The average diameter and shell thickness of the produced microcapsules were characterized using Scanning Electron Microscopy (SEM). Mortar mixes were prepared for various calcium nitrate concentrations of microcapsules that were encapsulated using the modified procedure. The compressive and flexural strengths and the elastic modulus of the mortar mixes were determined. The results show that the use of the modified encapsulation procedure resulted in a statically insignificant reduction of both compressive and flexural strengths compared to the original encapsulation method. The SEM micrographs of the fracture surface of the samples containing microcapsules showed that the strength reduction may be due to the agglomeration of the un-hydrated particles on the surface (shell) of the microcapsules. The compressive and flexural strengths of samples prepared using the proposed encapsulation procedure were enhanced compared to those prepared using previous encapsulation techniques.

CALCIUM NITRATE CONCENTRATIONS IN FERTIGATION FOR ‘TERRA’ BANANA PRODUCTION

ABSTRACT : The aim of this study was to evaluate the effect of calcium nitrate concentration of irrigation water on soil chemical attributes and productivity during the first ‘Terra’ banana crop cycle. The experiment followed a completely randomized design with six treatments and five replications, with six plants per plot. Treatments consisted in the use of three calcium nitrate concentrations (3.0, 10.0 and 13.0 g.L -1 ), applied via dripping and micro-micro-sprinkling irrigation. The results showed that the soil chemical properties under fertigation are influenced by the water and nutrient delivery system. There was a linear tendency of increase in electrical conductivity of the saturation extract and soil solution with the increase in calcium nitrate concentration in irrigation water. The banana tree productivity was influenced by the fertilizer concentration in irrigation water. PALAVRAS-CHAVE : soil solution, saturation extract, electric conductivity, trickle irrigation