scholarly journals Key factors affect selenite absorption in wheat leaf blades: pH, temperature, light intensity and leaf position

2020 ◽  
Vol 66 (No. 9) ◽  
pp. 431-436
Author(s):  
Lianhe Zhang ◽  
Liu Sinan ◽  
Yu Feiyan ◽  
Fu Zihao ◽  
Yang Jinyong ◽  
...  

Foliage-spraying selenite solution is an effective measure to enhance selenium (Se) concentration in wheat grains. However, how pH, temperature, light intensity, and leaf position affects selenite absorption in wheat leaf blades is not fully understood. In this study, the effects of pH, temperature, light intensity, and leaf position on selenite absorption in wheat leaf blades were investigated. The results indicated that the selenite absorption rate dramatically decreased with increasing pH. Further study revealed that aquaporin inhibitors such as HgCl<sub>2</sub> and AgNO<sub>3</sub> strongly inhibited selenite absorption at pH 3.0. Light and higher temperatures significantly promoted selenite absorption. Newly expanded leaf blades had higher rates of selenite absorption than younger and older leaf blades. Thus, higher rates of selenite absorption in leaf blades should attribute to the entrance of selenite into mesophyll cells via aquaporins in the form of H<sub>2</sub>SeO<sub>3</sub> at low pH values. Foliage-spraying selenite solution on upper leaf blades at lower pH values benefited to increase the selenite absorption rate in wheat leaf blades.  

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jui-Jung Chuang ◽  
Yu-Ya Huang ◽  
Szu-Hsuan Lo ◽  
Tzu-Fang Hsu ◽  
Wen-Ying Huang ◽  
...  

A vast majority of alginate particles exist as spheres in most practical uses, and both the particle shape and size are the key factors dominating the applications and performance of alginate gels. Therefore, it becomes an issue of great interest to investigate the aspheric alginate particles. As the first step, various shaped alginate particles were formed due to various pH values in gelation solutions. It was experimentally demonstrated that a low pH brought about an oblate shape, and particularly lower concentrations of both alginate and divalent cations resulted in a flattened oblate shape. Ba2+acting as a cross-linker had a less impact on the particle shape than Ca2+due to a higher affinity in alginate intermolecular cross-linking. With a larger surface area, an oblate particle offered a higher release rate than a spheric one.


2014 ◽  
Vol 960-961 ◽  
pp. 462-468 ◽  
Author(s):  
Yong Qiu ◽  
Hui Wu ◽  
Guang Qian Luo ◽  
Hong Yao

Gaseous oxidized mercury (Hg2+) in the flue gas is soluble in water and can be captured effectively by Wet flue gas desulfurization (WFGD) system. But in some extent Hg0re-emission happens due to the reduction of absorbed Hg2+, and the pH of slurry is an important factor affecting Hg0re-emission. In this study, the theoretical formulas of slurry pH were derived through the conventional solution theory and then were used to evaluate the factors determining the pH of slurry. A series of laboratory experiments were carried out under N2,CO2and O2/N2atmosphere to measure the Hg0re-emission tendency at different pH values. The results show that the higher the pH, the less Hg2+reduced by S(IV), resulting in the decrease of Hg0re-emission. Under N2atmosphere, the Hg0re-emission was mild at pH>4 while it was dramatic at pH<4. Under O2/N2atmosphere, the addition of O2extended the time span of Hg0re-emission at low pH and increased Hg0re-emission unexpectedly in the latter part of the experiments at high pH. CO2atmosphere almost did not affect Hg0re-emission because of its little effect on the slurry pH.


1988 ◽  
Vol 74 (4) ◽  
pp. 403-406 ◽  
Author(s):  
Leif Sestoft ◽  
Michael O. Marshall

1. The effects of medium glucose concentration (0–20 mmol/l) and flow (100–33% of normal) on lactate uptake at low lactate concentration were studied in perfused livers from 48-h-starved rats with perfusate pH values of 7.4 and 6.8. 2. Lactate uptake was independent of glucose concentration in the range 5–10 mmol/l, but was slightly inhibited with time at 20 mmol/l glucose. This pattern was independent of perfusate pH. 3. At both pH values lactate uptake decreased proportionally with flow, and at low flow lactate was produced by the livers. The effect of flow was greatest at pH 7.4 where a net lactate production was found at 48% of normal flow, whereas at pH 6.8 lactate production was not seen until the flow was reduced to 33% of normal. 4. When glucose was omitted from the perfusate lactate production ceased at both pH values. 5. The effect of low pH on lactate uptake and production in liver probably reflects inhibition of glycolysis by low pH.


1974 ◽  
Vol 141 (2) ◽  
pp. 555-565 ◽  
Author(s):  
G. W. Jameson ◽  
D. T. Elmore

Affinity adsorbents for bovine trypsin were prepared by covalently coupling p-(p′-amino-phenoxypropoxy)benzamidine to cellulose and to agarose. Trypsin binds to both adsorbents at pH6–8 and is released at low pH values or in the presence of n-butylamine hydrochloride. Pure β-trypsin may be eluted from crude trypsin bound at pH8.0 to the cellulose adsorbent by stepwise elution with an acetate buffer, pH5.0. Both α- and β-trypsin may be isolated by chromatography of crude trypsin on the agarose derivative in an acetate buffer, pH4.0. These two methods for purifying the trypsin are specific to the particular adsorbents. They are rapid and convenient in use. Both methods leave a mixture of the two enzymes bound to the adsorbent and release occurs only at low pH values. The effects of pH, composition and ionic strength of buffer and other variables on both purification methods are described. Affinity adsorbents of soya-bean trypsin inhibitor and of N-α-(N′-methyl-N′-sulphanilyl) sulphanilylagmatine bound to agarose were prepared, but were found to be of limited usefulness in the purification of trypsin.


2019 ◽  
Vol 65 (No. 12) ◽  
pp. 609-614
Author(s):  
Lianhe Zhang ◽  
Jinyong Yang ◽  
Zihao Fu ◽  
Yihan Fu ◽  
Sinan Liu ◽  
...  

Selenium (Se) deficiency in the human diet is a widespread problem. Se biofortification of wheat crop by spraying foliage with selenite could effectively increase Se intake by enhancing the Se concentration in wheat grains. However, pathway and driving forces of selenite absorption in wheat leaf blades are not fully understood. In this study, the effects of selenite-applied concentration, selenite-exposed duration, stomatal inhibitors, respiratory inhibitors, and competitive anions on selenite absorption in wheat leaf blades were investigated. The results indicated that the selenite absorption rate increased linearly with increasing selenite concentrations, but it decreased greatly and reached a low level with treatment times of 4 h and longer. Stomatal inhibitors significantly inhibited selenite absorption. Respiratory inhibitors and inorganic phosphate (P<sub>i</sub>) strongly inhibited selenite absorption. Therefore, selenite passively enters wheat leaf blades via cuticle and stomata, and then enters mesophyll cells via P<sub>i</sub> transporters. Concentration gradients and selenite uptake by mesophyll cells provide continual driving forces for selenite absorption in leaf blades.


1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.


Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.


2011 ◽  
Vol 77 (10) ◽  
pp. 3406-3412 ◽  
Author(s):  
Gino Vrancken ◽  
Luc De Vuyst ◽  
Tom Rimaux ◽  
Joke Allemeersch ◽  
Stefan Weckx

ABSTRACTSourdough is a very competitive and challenging environment for microorganisms. Usually, a stable microbiota composed of lactic acid bacteria (LAB) and yeasts dominates this ecosystem. Although sourdough is rich in carbohydrates, thus providing an ideal environment for microorganisms to grow, its low pH presents a particular challenge. The nature of the adaptation to this low pH was investigated forLactobacillus plantarumIMDO 130201, an isolate from a laboratory wheat sourdough fermentation. Batch fermentations were carried out in wheat sourdough simulation medium, and total RNA was isolated from mid-exponential-growth-phase cultures, followed by differential gene expression analysis using a LAB functional gene microarray. At low pH values, an increased expression of genes involved in peptide and amino acid metabolism was found as well as that of genes involved in plantaricin production and lipoteichoic acid biosynthesis. The results highlight cellular mechanisms that allowL. plantarumto function at a low environmental pH.


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