The Dependence of Some Photosynthetic Parameters on the Phosphorus Concentration in a Nutrition Solution and Wheat Genotype

1990 ◽  
pp. 3669-3672
Author(s):  
Slobodanka Zatezalo ◽  
Živko Stanković ◽  
Miloje R. Sarić
Author(s):  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova

Identification of water masses in areas with complex water dynamics is a complex task, which is usually solved by the method of expert assessments. In this paper, it is proposed to use a formal procedure based on the application of the method of optimal multiparametric analysis (OMP analysis). The data of field measurements obtained in the 68th cruise of the R/V “Academician Mstislav Keldysh” in the summer of 2017 in the Barents Sea on the distribution of temperature, salinity, oxygen, silicates, nitrogen, and phosphorus concentration are used as a data for research. A comparison of the results with data on the distribution of water masses in literature based on expert assessments (Oziel et al., 2017), allows us to conclude about their close structural similarity. Some differences are related to spatial and temporal shifts of measurements. This indicates the feasibility of using the OMP analysis technique in oceanological studies to obtain quantitative data on the spatial distribution of different water masses.


2020 ◽  
Vol 80 (03) ◽  
Author(s):  
Renu Pandey ◽  
Surendra Kumar Meena ◽  
Gayacharan . ◽  
Madan Pal Singh

Experiments were conducted to study the genotypic variability for tolerance to combined stresses of low availability of phosphorus (P) and drought in 14 mungbean [Vigna radiata (L.) R. Wilczek] accessions. The accessions were evaluated under four conditions viz., control (sufficient P, irrigated), low P (without P, irrigated), drought (sufficient P, withholding irrigation) and combined stresses (low P, withholding irrigation). The relative stress tolerance was estimated for 22 agro-physiological traits. The principal component analysis (PCA) and relative stress indices (RSIs) of traits exhibited significant variation among the treatments and accessions. Based on RSIs, the PCA ranking analysis showed that the accessions IC 280489, PDM 139 and IC 76491 were highly ranked and tolerant to low P, drought and combined stresses. The relative increase in component traits such as photosynthetic parameters, relative water content, above-ground biomass, seed P content and number of pods plant–1 were higher while canopy temperature and water use efficiency were reduced in tolerant accessions. In contrast, IPM 2-3 was found to be relatively sensitive to all three treatments. Tolerant accessions may be either included in the breeding program or used directly as cultivar that can be grown under low P and drought.


1992 ◽  
Vol 27 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Sonia Paulino Mattos ◽  
Irene Guimarães Altafin ◽  
Hélio José de Freitas ◽  
Cristine Gobbato Brandão Cavalcanti ◽  
Vera Regina Estuqui Alves

Abstract Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.


1994 ◽  
Vol 30 (5) ◽  
pp. 177-186 ◽  
Author(s):  
Karin Sundblad ◽  
Andrzej Tonderski ◽  
Jacek Rulewski

Nitrogen and phosphorus concentration data representing samples collected once a month for nine months at 13 locations along the Vistula River are considered in a preliminary discussion of the sources of the nutrients transported to the Baltic Sea. Concentrations in relation to flow data indicated substantial differences between subbasins. Based on those differences, on the area-specific nutrient loss for a six-month period and on the wastewater discharge in each subbasin, four regions could be recognized in the river basin: i) the southern region with a large impact of point sources, ii) the south central region, where diffuse sources seemed to be of major importance, iii) the north central region with a combined effect of point and diffuse sources, and retention in two reservoirs, iv) the northern region where point sources seemed to be the dominating source, at least for phosphorus. Our results illustrate the importance of differences in phosphorus retention between the basins. Long-term retention along the course of the river, particularly in the two reservoirs, must be estimated to allow proper source apportionment in the Vistula basin. Concentration decreases in the Wloclawek Reservoir varied between 44 and 68% for P, and 11 to 37% for N, in the months with significant retention. In some months, however, concentrations increased, indicating a release of nutrients.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 441-449 ◽  
Author(s):  
Paul J. Garrison ◽  
Timothy R. Asplund

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.


1998 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
S. C. Williams ◽  
J. Beresford

Thames Water have built a three-stage Bardenpho activated sludge plant to treat 50% of the wastewater flow at Slough in the United Kingdom. Following commissioning, the plant performed well in terms of nitrification and denitrification but did not produce an effluent with a low phosphorus concentration. One possible explanation for the poor performance was the mixing of the anaerobic zone. The flow characteristic of the anaerobic zone was identified by tracer tests and alternative mixing regimes were tested. The results showed that reducing the mixing energy in the anaerobic zone had no detrimental effect on the effluent quality. The plant has operated with the reduced mixing input for nine months and the effluent phosphorus concentration has been reduced from 2.1 mgl−1 to 0.8 mgl−1.


1997 ◽  
Vol 35 (2-3) ◽  
pp. 131-138 ◽  
Author(s):  
Pirjo-Riitta Rantala ◽  
Hannu Wirola

The aim of the study was to determine if solid, slightly soluble compounds can be used as nutrient source in activated sludge treatment plants instead of liquid phosphoric acid. Four different solid materials were tested in lab-scale solubility tests to find compounds which are least soluble. Two materials were chosen for further studies: apatite and raw phosphate. The use of apatite and raw phosphate as nutrient source was studied in lab-scale activated sludge reactors along with a control reactor where phosphorus was added in liquid form. The phosphorus dosage, measured as elementary phosphorus, was the same for all three reactors. The reactors were fed with pre-clarified chemi-thermomechanical pulp mill (CTMP) wastewater. There were no significant differences in the reductions of organic matter between the three reactors. The mean effluent concentration of total phosphorus was 3 mg P/l in the control reactor and less than 1 mg P/1 in the other two reactors. The soluble phosphorus concentration was more than 2 mg P/l in the control reactor and less than 0.5 mg P/l in the other two. Apatite was an even better nutrient source than raw phosphate. Further lab-scale tests were conducted using two different grain sizes of apatite. No significant differences were found between the studied grain sizes (<0.074 mm and 0.074 mm-0.125 mm). Apatite was then used in full-scale at a CTMP-mill two different times. The experiments showed that the mean concentrations of phosphorus can be reduced radically by using apatite as a nutrient source instead of liquid phosphorus. Solid phosphorus compounds are a viable alternative to reduce the phosphorus load from forest industry wastewater treatment plants.


2018 ◽  
Vol 46 (1) ◽  
Author(s):  
Elizabeth Schwegler ◽  
Augusto Schneider ◽  
Ana Rita Tavares Krause ◽  
Paula Montagner ◽  
Eduardo Schmitt ◽  
...  

 Background: Bovine mastitis causes major economic losses for milk producers by reducing the quantity and the quality of the milk or even leading to the complete loss of the mammary gland secretory capacity. During the transition period, dairy cows are susceptible to infectious diseases; therefore, markers that allow early identification of cows in higher risk of developing diseases are especially useful at this time. Therefore, the aim of this study was to evaluate serum markers in the pre and postpartum of multiparous dairy cows with clinical mastitis and with health condition in the postpartum period in a semi-extensive management system.Materials, Methods & Results: Thirty-Six Holstein cows were monitored daily during milking until 59 days postpartum and were categorized according to the pre-milking strip cup test into clinical mastitis (mastitis group (MG)) and absence of symptoms (control group (CG)) that were negative to the test, representing the health cows. All cows were reared as one group and maintained in a semi-extensive pasture-based system. Blood samples were collected weekly after morning milking via venipuncture of the coccinea vein into tubes without anticoagulant and grouped for prepartum (-21 to 0 days from calving), early postpartum (0 to 30 days from calving), and late postpartum (30 to 59 days from calving) periods. Milk production was recorded daily. The serum markers albumin, aspartate aminotransferase (AST), phosphorus, gamma-glutamyltransferase (GGT) and non-esterified fatty acids (NEFA) were measured. Statistical analyses were performed using SAS®. The cases of clinical mastitis occurred on average at 37.2 ± 4.9 days postpartum. Health cows (CG) had higher milk production compared to the mastitis group (MG) only in the late postpartum period (P < 0.05). There was no difference among groups for albumin and NEFA concentrations in all periods evaluated (P > 0.05). In the early postpartum period the AST activity was higher in CG than in MG (P = 0.02). The GGT enzyme tended to be more concentrated in the CG than in the MG during the early (P = 0.06) and late (P = 0.08) postpartum periods. Late postpartum phosphorus concentration was lower for MG than CG (P = 0.04). In the prepartum and early postpartum periods, there was no difference among groups for phosphorus concentration (P > 0.05).Discussion: A decrease in milk production in MG compared to CG observed in late postpartum period was due to the inci­dence of mastitis observed around 37 days postpartum. Cows that presented clinical mastitis in the postpartum period did not differ in the blood concentration of NEFA in the prepartum period. In the late postpartum period higher concentration of phosphorus was observed in the CG than in MG, indicating that animals affected by mastitis may be in the weakest energy status. Regarding liver health, the concentration of AST was higher in the recent postpartum period for CG, in disagree­ment with previous studies that related AST to tissue injury caused by mastitis. The GGT enzyme tended to had higher concentrations in CG than MG during the whole postpartum period and may be related to increased hepatic metabolism due to higher production. There were no changes in albumin levels among healthy and mastitis cows, indicating that this marker can not be used to predict clinical mastitis. There were no metabolic alterations in the prepartum period related to the occurrence of postpartum mastitis in multiparous cows in a semi-extensive management system.Keywords: AST, dairy cows, NEFA.


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