Root morphological changes in response to low phosphorus concentration in eucalypt species

Trees ◽  
2021 ◽  
Author(s):  
Samir Bichara ◽  
Paulo Mazzafera ◽  
Sara Adrian L. de Andrade
Keyword(s):  
Morphological Changes ◽  
Phosphorus Concentration ◽  
Eucalypt Species ◽  
Low Phosphorus

The effect of anaerobic zone mixing on the performance of a three-stage Bardenpho plant

1998 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
S. C. Williams ◽  
J. Beresford
Keyword(s):  
Detrimental Effect ◽  
Flow Characteristic ◽  
Tracer Tests ◽  
Poor Performance ◽  
Phosphorus Concentration ◽  
Effluent Quality ◽  
Mixing Energy ◽  
The United Kingdom ◽  
Low Phosphorus ◽  
Anaerobic Zone

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.

Removal of phosphorus from wastewater by activated alumina adsorbent

1997 ◽  
Vol 35 (7) ◽  
pp. 39-46 ◽  
Author(s):  
Tadashi Hano ◽  
Hirokazu Takanashi ◽  
Makoto Hirata ◽  
Kohei Urano ◽  
Shunji Eto
Keyword(s):  
Diffusion Coefficients ◽  
Aluminum Sulfate ◽  
Space Velocity ◽  
Intraparticle Diffusion ◽  
Phosphorus Concentration ◽  
Activated Alumina ◽  
Phosphorus Adsorption ◽  
Equilibrium Study ◽  
Rivers And Lakes ◽  
Low Phosphorus

The adsorption characteristics of activated alumina treated with aluminum sulfate were studied to develop a new removal process for low concentration phosphorus in the waters of rivers and lakes. The equilibrium study showed that the adsorption capacity was enhanced about 1.7-fold by treating with aluminum sulfate. The effective intraparticle diffusion coefficients, determined by the Boyd's method based on batch runs, were hardly affected by such a low phosphorus concentration as observed in the water of rivers and lakes under investigation. The temperature dependence of the intraparticle diffusion coefficients based on the concentration in solid showed the activation energy of 29.7kJ·mol−1, which was a little higher than that in usual pore diffusion. The maximum continuous operation term (regeneration cycle) of the present phosphorus adsorption system was estimated. Under the conditions of influent phosphorus concentration of 0.1 g·m−3, removal extent of 90%, particle size of 2 × 10−3m, temperature of 298K and space velocity of 1.39 × 10−3s−1 (5h−1), the present removal system remained effective for about 500 days.

Influence of low phosphorus concentration on leaf photosynthetic characteristics and antioxidant response of rice genotypes

2017 ◽  
Vol 55 (2) ◽  
pp. 285-293 ◽  
Author(s):  
N. Veronica ◽  
D. Subrahmanyam ◽  
T. Kiran ◽  
P. Yugandhar ◽  
V. P. Bhadana ◽  
...  
Keyword(s):  
Antioxidant Response ◽  
Photosynthetic Characteristics ◽  
Phosphorus Concentration ◽  
Low Phosphorus ◽  
Rice Genotypes

The role of vesicular-arbuscular mycorrhizas (VAM) in the phosphorus nutrition of cowpea (Vigna unguiculata (L.) Walp)

1991 ◽  
Vol 42 (1) ◽  
pp. 129 ◽  
Author(s):  
BM Ikombo ◽  
DG Edwards ◽  
CJ Asher
Keyword(s):  
Vigna Unguiculata ◽  
Phosphorus Deficiency ◽  
Phosphorus Nutrition ◽  
Strong Increase ◽  
Phosphorus Concentration ◽  
Sequence Of Events ◽  
Mycorrhizal Association ◽  
Low Phosphorus ◽  
Unsterilized Soil

An experiment was conducted to establish the role of VAM in the phosphorus nutrition and early growth of cowpea (Vigna unguiculata (L.) Walp.) cv. Vita 4 in a podzolic soil (Haplustult). The experiment involved four treatments: (1) plants grown in unsterilized soil adequately supplied with phosphorus (240 kg P ha-1), (2) plants grown in unsterilized soil with low phosphorus (10 kg P ha-1), (3) and (4) plants grown in methyl bromide sterilized soil with low phosphorus (10 kg P ha-1). Plants in treatments (1), (2) and (3) were inoculated with Bradyrhizobium. A series of harvests was taken from 14 to 42 days after sowing; 15 harvests at two-day intervals from treatment (2) and 5 harvests at 7-day intervals from the other treatments. Root infection by VAM did not occur in plants grown in the sterilized soil treatments (3) and (4); growth of these plants was poor, and they showed symptoms of severe phosphorus deficiency. Phosphorus concentrations in the youngest fully expanded leaf (YFEL) of plants grown in treatments (3) and (4) were in the range 0.10 to 0.16% at all harvests. Plants which were grown in the unsterilized soil with 240 kg P ha-l (treatment (1)) grew very well; they had a high concentration of phosphorus (0.3 1 to 0.75%) in the YFEL at all harvests and exhibited a delayed and reduced level of infection by VAM. Plants grown in the unsterilized soil with 10 kg P ha-l (treatment (2)) were strongly colonized by VAM; infection was apparent at 14 days after sowing and reached a maximum (85% of root segments colonized) at 36 days after sowing. A strong increase in phosphorus concentration in the YFEL of plants grown in treatment (2) commenced at 22 days after sowing, while an increase in dry matter yield and phosphorus content of the whole tops above that of non-mycorrhizal plants grown in the sterilized soil was observed at 30 days after sowing. The sequence of events leads us to conclude that the recovery of cowpea plants from early phosphorus deficiency stress resulted from increased phosphorus absorption following the development of a mycorrhizal association with the roots.

Comparative research on phosphorus removal by pilot-scale vertical flow constructed wetlands using steel slag and modified steel slag as substrates

2015 ◽  
Vol 71 (7) ◽  
pp. 996-1003 ◽  
Author(s):  
Yupan Yun ◽  
Xiaoqin Zhou ◽  
Zifu Li ◽  
Sayed Mohammad Nazim Uddin ◽  
Xiaofeng Bai
Keyword(s):  
Constructed Wetlands ◽  
Phosphorus Removal ◽  
Steel Slag ◽  
Pilot Scale ◽  
Phosphorus Concentration ◽  
Vertical Flow ◽  
Phosphorus Adsorption ◽  
Vertical Flow Constructed Wetlands ◽  
Low Phosphorus ◽  
Set Up

This research mainly focused on the phosphorus removal performance of pilot-scale vertical flow constructed wetlands with steel slag (SS) and modified steel slag (MSS). First, bench-scale experiments were conducted to evaluate the phosphorus adsorption capacity. Results showed that the Langmuir model could better describe the adsorption characteristics of the two materials; the maximum adsorption of MSS reached 12.7 mg/g, increasing by 34% compared to SS (9.5 mg/g). Moreover, pilot-scale constructed wetlands with SS and MSS were set up outdoors. Then, the influence of hydraulic retention time (HRT) and phosphorus concentration in phosphorus removal for two wetlands were investigated. Results revealed that better performance of the two systems could be achieved with an HRT of 2 d and phosphorus concentration in the range of 3–4.5 mg/L; the system with MSS had a better removal efficiency than the one with SS in the same control operation. Finally, the study implied that MSS could be used as a promising substrate for wetlands to treat wastewater with a high phosphorus concentration. However, considering energy consumption, SS could be regarded as a better alternative for substrate when treating sewage with a low phosphorus concentration.

Dietary cholecalciferol lowers the maximal activity of intestinal mucosa phytase in ducklings fed low-phosphorus diets

2011 ◽  
Vol 91 (3) ◽  
pp. 399-404
Author(s):  
E. M. Onyango ◽  
O. Adeola
Keyword(s):  
Total Phosphorus ◽  
Intestinal Mucosa ◽  
Maximal Activity ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Total Phosphorus Concentration ◽  
Ileal Digestibility ◽  
Low Phosphorus ◽  
The Individual

Onyango, E. M. and Adeola, O. 2011. Dietary cholecalciferol lowers the maximal activity of intestinal mucosa phytase in ducklings fed low-phosphorus diets. Can. J. Anim. Sci. 91: 399–404. The role of cholecalciferol and phosphorus in the regulation of intestinal mucosa phytase was investigated in White Pekin ducklings. Ninety-six 7-d-old male ducklings were grouped by weight into six blocks of four cages with four ducklings per cage. The average weights of the individual birds in the six subgroups were: 282, 270, 263, 255, 247 and 236 g, respectively. Four corn-soybean meal-based mash diets were randomly assigned to cages within each block. The four diets consisted of cholecalciferol at 0 or 75 µg kg–1 and total phosphorus at 3.6 or 7.0 (or 0.12 or 0.46 available phosphorus, respectively) g kg−1 in a 2×2 factorial arrangement. Birds were fed the experimental diets for 9 d under conditions that excluded ultraviolet light. Ducklings fed diets with cholecalciferol concentration at 75 µg kg−1 of diet showed a lower maximal activity and Km value of intestinal mucosa phytase (P<0.05), and higher apparent ileal digestibility of calcium (P<0.0001). Ducklings fed diets with total phosphorus concentration at 7.0 g kg−1 of diet showed no change in intestinal mucosa phytase activity, but had higher weight gain, feed intake, tibia ash, ileal digestibility of phosphorus (P<0.0001), and feed efficiency (P<0.001). In conclusion, dietary cholecalciferol decreased the maximal activity and Km value of intestinal mucosa phytase in ducklings fed low-phosphorus diets.

Phytase and cholecalciferol supplementation of low-calcium and low-phosphorus diets for pigs

1998 ◽  
Vol 78 (3) ◽  
pp. 307-313 ◽  
Author(s):  
O. Adeola ◽  
J. I. Orban ◽  
D. Ragland ◽  
T. R. Cline ◽  
A. L. Sutton
Keyword(s):  
Weight Gain ◽  
Growth Performance ◽  
Control Diet ◽  
Dietary Calcium ◽  
Positive Control ◽  
Phosphorus Concentration ◽  
Low Calcium ◽  
Low Phosphorus ◽  
Cholecalciferol Supplementation ◽  
Plasma Phosphorus

The effects of different levels of calcium, phytase, and cholecalciferol in low-phosphorus diets were studied in individually-penned 20-kg pigs for 28 d. The positive control diet, used in all three experiments, was formulated to contain 6 g Ca and 5.4 g P kg−1. In the first experiment, four barrows and four gilts received one of seven diets arranged as a positive control plus 2 × 3 factorial of phytase (0 or 1, 600 units kg−1) and calcium (3, 4.5 or 6 g kg−1) containing phosphorus at 3.4 g kg−1. Phytase addition increased (P < 0.05) plasma phosphorus concentration, weight gain and gain:feed ratio. Plasma phosphorus, weight gain and gain:feed ratio were linearly reduced (P < 0.05) as dietary calcium level increased in the low-phosphorus diets but not in the phytase-supplemented low-phosphorus diets. The second experiment was similar to the first experiment, except that phytase was reduced to 800 units kg−1 and dietary calcium levels were 2.5, 3, or 3.5 g kg−1. Phytase addition increased (P < 0.05) weight gain, gain:feed ratio, plasma phosphorus and calcium. A low-calcium (3.5 g kg−1), low-phosphorus (3.4 g kg−1) diet was supplemented with phytase (0 or 800 units kg−1) and cholecalciferol (0 or 800 ug kg−1) in a 2 × 2 factorial arrangement plus a positive control in the third experiment. Growth performance was similar (P > 0.1) among pigs that received the positive control and the phytase- or cholecalciferol-supplemented low-calcium, low-phosphorus diets. These results demonstrate that high dietary calcium in a low-phosphorus diet depresses pig performance and that phytase or cholecalciferol supplementation of a low-calcium (3.5 g kg−1), low-phosphorus (3.4 g kg−1) diet produces similar growth performance as a diet with adequate calcium (6 g kg−1) and phosphorus (5.4 g kg−1) when fed to 20-kg pigs. Key words: Pigs, phytase, cholecalciferol, phosphorus, calcium

scholarly journals Characteristics of phosphorus sorption at the sediment–water interface in Dongting Lake, a Yangtze-connected lake

2016 ◽  
Vol 47 (S1) ◽  
pp. 225-237 ◽  
Author(s):  
Wei Huang ◽  
Kun Wang ◽  
Hongwei Du ◽  
Ting Wang ◽  
Shuhang Wang ◽  
...  
Keyword(s):  
Fine Particles ◽  
Sorption Isotherms ◽  
Physicochemical Characteristics ◽  
Dongting Lake ◽  
Phosphorus Concentration ◽  
Phosphorus Sorption ◽  
Sediment Samples ◽  
Low Phosphorus ◽  
Phosphorus Source ◽  
Sorption Characteristics

Phosphorus in sediments plays an important role in lake eutrophication. This study investigated the phosphorus sorption characteristics of sediments in a river-connected lake and identified the phosphorus source or sink areas in the lake. Sediment samples with different physicochemical characteristics were collected in 2011 and 2013 from Dongting Lake, which is connected to the world's third longest river, the Yangtze. Batch incubation experiments were conducted to determine the phosphorus sorption characteristics of the sediment samples. The sediment sample from Luzui (D3) exhibited the highest sorption capacity in 2013 (0.75 mg g−1) because of its large proportion of fine particles (&lt;63 μm). Results of sorption isotherms illustrated that the modified Langmuir model can effectively describe the sorption isotherms (R2 &gt; 0.91). The calculated results (equilibrium phosphorus concentration, 0.025–0.032 mg L−1) indicated that the estuary from Dongting Lake to the Yangtze River (D1) served as a phosphorus sink because of the large proportion of fine particles and low total phosphorus content in the sediments. The east Dongting Lake (D2 and D3) with a high phosphorus concentration served as a phosphorus source. Yugong Miao (D4) and Nanzui (D5) had a low phosphorus concentration in water because of their location and flow field, respectively.

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