Short-Term Ion Uptake by Phalaenopsis as Affected by Concentration of the Solution

ABSTRACT

Nutrient uptake over a 72 h culture period by clonal micropropagules of Phalaenopsis Tanigawa × Yukimai Dream ‘KS 370’ and ‘KS 352’ were surveyed by Ichihashi's (1997) Ichihashi, S. 1997. “Orchid production and research in Japan”. In Orchid Biology, Reviews and Prospectives, Edited by: Arditti, J. and Pridgeon, A. M. 171–212. Dordrecht, , The Netherlands: Kluwer.  [Google Scholar] nutrient solution at the original ion strength and its half and quarter. Uptake of major anions [nitrate (NO₃ ^?), phosphate (H₂PO₄ ^?), and sulfate (SO₄ ^2?)] and cations [ammonium (NH₄ ⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺)] measured with an ion chromatograph increased as the ionic strength of the solution increased in both cultivars. The final uptake rates of nutrients were 0.8, 2.0, 2.1, 1.2, 3.0, 2.0, and 1.6 me L^?1, respectively in the order of ions mentioned above. The ratios of the uptake rates between cations (mono or bivalent) were almost in proportion to the ratio of their initial ion strength. Therefore, no antagonistical absorption of cations was found in that ion strength. Leaf content of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and copper (Cu) increased as the ionic strength of the solution increased, but concentrations of iron (Fe), manganese (Mn), and zinc (Zn) were not affected significantly. Nitrogen (N) content of leaves in ‘KS 370’ after 72 h culture increased significantly by increasing the ionic strength of the solution. Root concentrations of P, K, Ca, Mg, and Fe increased as the ionic strength of the solution increased in both cultivars. The N concentrations of roots in either ‘KS 370’ or ‘KS 352’ had positive correlations with an increasing ionic strength of the solution, although they were constantly greater in ‘KS 370’ than in ‘KS 352’. The greatest fresh weight was obtained when the plants were cultured in a half strength solution. Whereas dry weight decreased in all treatments as the ionic strength of the solution decreased. These findings show that increased ion absorption affected plant dry weight. The obtained findings provide fundamental information for the closed hydroponic system of phalaenopsis cultivation.     

Uptake of zinc by Brassica napus as affected by sulphur supply

Industrial crops provide a possibility for utilization of heavy metal polluted soils. Knowledge of the factors which affect metal uptake by crops is therefore essential in order to develop concepts for the management of such soils. In pot experiments the uptake of Zn by oilseed rape increased considerably with the Zn supply. The increase of Zn uptake was counteracted partly by S. This protective effect of S was, however, not related to Zn retention in the roots.     

Uptake of Cu2+ by starch granules as affected by counterions

Potato and wheat starch granules were soaked in 1% aqueous solutions of copper(II) salts: acetate, chloride, and sulfate. Such treatment caused sorption of Cu(2+) ions at the granule surface and their penetration into the granule interior as was proven, for sectioned granules of investigated starch, by scanning electron microscopy combined with an X-ray microanalysis system (energy dispersive spectroscopy). Copper ions incorporated into the granules influenced the starch thermal stability. Uptake of Cu(2+) by potato, determined by flame atomic absorption spectrometry, was much higher than obtained for the wheat starch. Moreover, it was dependent on copper counteranions present in the solution. In all investigated granules, the most effective sorption occurred in the acetate solution. Starch dehydration or/and freezing and thawing, affecting the water-dependent inner structure of the granules, also influenced the amount of Cu(2+) taken from the solutions. Thus, compared to that in native starch, this value was considerably higher in Cu(CH 3COO)2, almost unchanged in CuSO4, and significantly lower in the case of CuCl2 solution. The influence of chloride and sulfate anions seemed to correlate with their water structure-making and structure-breaking ability, affecting the migration of Cu(2+) in the amorphous parts of the granules. However, high Cu uptake observed for acetate solution could be explained on the basis of acetate anion hydrolysis activating the polysaccharide matrix for cation binding. The obtained results provide new information about interactions of starch granules with salt solution and therefore support our understanding of starch properties.     

Cadmium Uptake by Cowpea and Mungbean as Affected by Cd and P Application

A green house experiment was conducted to determine the interactive effects of cadmium (0, 2.5, 5, 10, and 20 mg Cd kg-1 soil) and phosphorus (0, 20 and 40 mg P kg-1 soil) on dry matter yield of cowpea and mungbean, and tissue concentration and uptake of cadmium (Cd) and Phosphorus (P). Application of Cd to soil decreased the dry matter yield of both the crops significantly at each level of applied P. Phosphorus application, on the other hand, increased the dry matter yield of both crops significantly at each level of Cd additions to the soil. Cadmium concentration in plant tissue and uptake of Cd by plants increased markedly with the increasing rates of Cd in the soil. The magnitude of increase in tissue Cd concentration, however, was higher in the absence than in the presence of added P. Consequently, the concentration of Cd in plants decreased with increasing levels of P application to the soil. This decrease in tissue Cd concentration with increasing P supply in the soil was mainly attributed to increased dry matter yield of crops. The concentration of P in cowpea and mungbean tissue increased while the uptake of P by these crops decreased markedly with increasing levels of Cd in the soil, irrespective of the rates of P applied.     

Mineral Elements Uptake and Growth of Strawberry as Influenced by Organic Substrates

Pot experiment was conducted in a greenhouse to compare the effect of four organic substrates [S1: Persian turpentine trees leaf mold (50%) + Soil (50%); S2: Oak leaf mold (50%) + Soil (50%); S3: Cypress leaf mold (50%) + Soil (50%) and S4: liquorice processing wastes (50%) + Soil (50%)] application on strawberry growth, yield, and nutrient concentration, and on some soil properties. Results showed that leaves mold and liquorice wastes application decreased pH, increased soil organic matter, and increased soil concentrations in all mineral elements studied, except for potassium (K). The amount of mineral elements in substrates had also a great influence on the leaf nutrient concentrations. High levels of nitrogen (N), K, iron (Fe), manganese (Mn), and zinc (Zn) were obtained in leaves; while phosphorus (P) concentration was lower than sufficient levels. Although, strawberry fresh and dry weights and leaf chlorophyll content were significantly higher in plants grown in S4 with no added fertilizer, the highest fruit yield was obtained in combination substrates with 50% fertilizer. Our results indicate that use of leaf mold and liquorice wastes in soil mixtures can reduce the amount of fertilizer required for optimum strawberry plant growth and yield.     

Hairy Vetch Incorporated as Green Manure Inhibits Sulfathiazole Uptake by Lettuce in Soil

Veterinary antibiotics like sulfonamides are frequently detected in arable lands and they can potentially contaminate food crops. It is thus of great importance to identify strategies to reduce food crops’ uptake of antibiotics. For the first time, using a pot culture experiment, sulfathiazole (STZ) uptake by lettuce (Lactuca sativa L.) grown in antibiotic-contaminated soils (10 and 100 mg STZ kg^?1 soil) and treated with (in)organic amendments, namely chemical fertilizer (NPK), compost, and hairy vetch, was investigated. Subsequent enhanced plant growth was witnessed when using hairy vetch treatment. The amount of antibiotic uptake was significantly reduced to 5 and 33% with hairy vetch application compared to compost or NPK application at 10 and 100 mg kg^?1 STZ, respectively. The total amounts of accumulated STZ in plant parts increased as the levels of STZ contaminated in soils were increased. STZ was much more abundant in the roots than the leaves. Within 30 days, the extractable STZ in the treated soils—especially with hairy vetch—diminished considerably to concentrations that are frequently detected in arable soils. We conclude that utilization of green manure (cover crop—hairy vetch) is a viable strategy for safer crop production in antibiotic-contaminated soils.     

油冬菜对水凝胶包裹~(14)C-多菌灵的吸收及其在土壤-油冬菜体系中的可提态残留和结合残留

利用高吸水树脂(SAP)和农药解决干旱半干旱地区抗旱保水及虫害问题是行之有效的农业生产措施,研究并阐明SAP与农药共存下的农药环境行为规律以保障环境安全性具有重要的实际意义。本文以具有缓释特性的水凝胶包覆多菌灵(H-MBC)为研究对象,应用同位素示踪法研究14C标记H-MBC在水中的释放特性及其与原药(14C-MBC)在土壤-油冬菜体系中的结合残留、可提态残留、矿化及挥发物总量的异同性,同时考察油冬菜对14C标记H-MBC的吸收利用规律。结果表明,H-MBC可以实现多菌灵缓慢释放,48 h释放了总量的60%,至360 h时释放量达到了总量的96%;14C标记H-MBC及14CMBC在土壤中可提态残留均随着时间递减,至培养34 d时分别占引入量的10.70%和6.95%;14C标记H-MBC及14C-MBC在土壤中的结合残留随着时间先增后降,其拐点分别出现在28 d和14 d,其中14C标记H-MBC的结合残留约占引入量35.71%~52.51%,而对照14C-MBC的结合残留约为引入量的23.87%~43.26%;油冬菜对14C标记H-MBC和14C-MBC的吸收均较少,仅占引入量的0.08%~1.64%,表明2种施药方式下多菌灵均不会在植物中产生大量残留。根据质量平衡得到的14C标记HMBC和14C-MBC降解产生的挥发性物质(可能为14C-CO2和/或14C-甲酸)的量分别为30.17%~52.66%和32.26%~65.75%,凝胶的包覆减少了多菌灵挥发性物质的产生。本研究为干旱地区安全、科学使用SAP和农药提供了科学依据。     

Predicting Metal Uptake and Risk to the Human Food Chain from Leaf Vegetables Grown on Soils Amended by Long-Term Application of Sewage Sludge

The success of risk assessment of metal contaminated soils depends on how precisely one can predict the bio-availability of metals in soil and transfer to the human food chain. In the present investigation, we tested several formulations of the ‘free-ion activity model (FIAM)’ to predict uptake of Cd, Zn and Cu by perpetual spinach (Beta vulgaris, Cicla) grown on a range of soils amended with sewage sludge. The model was parameterised using data measured on samples of pore water extracted by centrifugation and with porous Rhizon samplers installed within the rhizosphere of the growing plants. Free ion activities (M²⁺) were estimated following speciation of solution data using version 6 of the ‘Windermere Humic Aqueous Model (WHAM-VI). For all three metals, the best formulation of the FIAM appeared to require only one hypothetical root sorption site without competition from protons. Values of (M²⁺) could also be predicted satisfactorily from a pH-dependent Freundlich relation. Thus, from a combined FIAM–Freundlich relation and population dietary information, it was possible to estimate risk (hazard quotients) to consumers from very simple soil measurements: extractable metal content (0.05 M EDTA (Zn and Cu) or 1 M CaCl₂ (Cd)), soil humus content and pH. The role of increased soil organic matter content and soil pH, in reducing risk to consumers, is illustrated for Cd in a hypothetical soil at the current UK statutory Cd limit for sludge application to agricultural land.     

Uptake and distribution of selenium in tomato plants as affected by genotype and sulphate supply

Aim of this work was to investigate if the variation among tomato genotypes in selenium (Se) uptake and accumulation observed in short term experiments are maintained over longer growth periods and if there is a positive correlation in shoot between sulphur (S) accumulation and Se accumulation across different genotypes or if higher tissue S results in greater feedback inhibition of Se uptake. Two experiments were carried out under greenhouse conditions and different genotypes of Lycopersicon lycopersicum (UC82B and LA2711), Lycopersicon pennellii (LA716) and Lycopersicon peruvianum (LA2157) were grown until fruit ripening. The results obtained in the two experiments confirmed that sulphate in the growth solution reduced selenate uptake by plants and increased the S content of the leaves. Under low sulphate treatment there was a clear correlation (R²=0.82) between leaf S content and shoot Se content across genotypes in both experiments, indicating that the overall activity of the S transport systems also determines Se transport. Selenium was translocated from shoot to fruit, but the edible portion of the plant contained much less total Se than the inedible plant parts. The difference in Se content between the low and the high sulphate treatments was significantly higher in shoot than in root, confirming that the Se translocation from root to shoot is probably more affected by high sulphate supply than Se uptake by root. In the first experiment the genotype LA716 showed ah higher Se, accumulation together with higher S content in leaves, indicating a marked ability of this genotype to absorb ions from substrate. In the second experiment UC82B appeared to be more capable to accumulate Se and S rather than LA2711 and LA2157. In both experiments Lycopersicon peruvianum appeared to be less affected by the high concentration of ions in the growth solution and to be able to reduce ion uptake than Lycopersicon lycopersicum and Lycopersicon pennellii.     

Uptake of cations by annual ryegrass as related to cations adsorbed onto root exchange sites

Abstract

Previously published results on exchange capacities for Ca²⁺, Mg²⁺, Mn²⁺, and K⁺ in the Donnan free space of roots of two ryegrass cultivars (Lolium multiflorum Lam. cv. Marshall and Wilo) grown at two Al levels in the nutrient solution (0 and 74 μM) were correlated with the average net uptakes of the same cations. For Al‐treated plants regressed separately, significant correlations r=0.906 and r=0.963 were found for Mn²⁺ and Ca²⁺/Mg²⁺, respectively. No significant correlations were observed for these cations in control plants. In contrast, when data of control and Al‐treated plants were combined, significant linear correlations r=0.805, r=0.924, and r=0.968 were found for Ca²⁺, K⁺, and K⁺/(Ca²⁺+Mg²⁺)^1/2, respectively. The influence of cations adsorbed onto the root exchange sites and the effect of Al on the cation uptake processes were discussed.     

Yield Responses of Wheat to Ozone Exposure as Modified by Drought-Induced Differences in Ozone Uptake

Over a period of two years greenhouse experiments were carried out to quantify the interaction ozone exposure × water stress in winter wheat (Triticum aestivum L. cv. Perlo). Assessment of effects carried out on various yield parameters showed that abundant water supply made the plants most sensitive to ozone exposure. In well-watered plants (75%) of soil water capacity, s.w.c.), the AOT40 ozone exposure doses of 26.8 and 24.9 μmol mol^-1 hr^-1 (ppm.h) caused grain yield reductions by 35 and 39%. No reductions of yields were observed at severe water stress (35% of s.w.c.) condition. The decrease in ozone responsiveness under drought can be explained by a distinct reduction in ozone uptake (18 vs. 2 mmol m^-2 in well-watered vs. severely stressed plants at the same ozone exposure). The calculations of ozone uptake were based onrepeated measurements of leaf conductance. Generally curvi-linear regression functions explained the dependence of relative yield on ozone and on water stress better than multiple simple linear regression functions. The consideration of ozone uptake instead of ozone exposure improved the performances of the models further. For explaining grain yield, 96.8% of the variances could be explained by a model resulting from curvi-linear regression fitting. A suggestion for calculating correction factors to modify critical levels in the case of limited water supply is presented.     

Uptake of selenium by freshwater phytoplankton

The uptake of three forms of Se, selenate, selenite and selenomethionine, was examined in three species of freshwater algae, Anabaena flos-aquae (Cyanophyceae), Chlamydomonas reinhardtii (Chlorophyceae), and Cyclotella meneghiania (Bacillariophyceae) in a defined medium using radiotracers at Se concentrations representative of contaminated systems. Based on the relative accumulation by live vs. heat-killed cells, and linear accumulation through time, selenate accumulation by all three species appears to be a physiological process. However, selenite accumulation at these concentrations appears to be due largely to sorption rather than active uptake, as shown by rapid initial accumulation and the fact that accumulation by heat-killed cells was nearly equal to that of dead cells. Both selenate and selenite uptake rates increased linearly with concentration over the range of 1 to 50 µg L^–1. Selenomethionine uptake is a biological process with saturable uptake kinetics (K_s ranging from about 2 to 30 µg L^–1 Se), with much greater uptake rates than the other two forms, and little inactive sorbtion to heat-killed cells.     

Yield,Nutrient Uptake,and Quality of Stevia as Affected by Organic Sources of Nutrient

A field experiment was conducted during 2008 and 2009 at the Council of Scientific and Industrial Research-Institute of Himalayan Bioresource Technology, Palampur, India, to study the effect of organic sources of nutrient on yield, nutrient uptake, fertility status of soil, and quality of stevia crop in the western Himalayan region. The experiment comprised eight different combinations of organic manure [farmyard manure (FYM), vermicompost (VC), and apple pomace manure (AP)]. Total leaf dry biomass increased by 149% over the control with application of VC 1.5 t ha^?1 + AP 5 t ha^?1. Application of organic manures enhanced organic carbon and available nutrient status of soil more than the control. Nitrogen (N) and phosphorus (P) content in stem were significantly affected by the application of organic manures over the control. Stevia plants supplied with FYM 10 t ha^?1 + AP 2.5 t ha^?1 recorded more total glycoside than other treatments. Stevioside yield (kg ha^?1) was greater with application of FYM 10 t ha^?1 + AP 2.5 t ha^?1.     

Uptake of uranium by vegetables and rice

The uptake of U by vegetables from soil and water has been studied in pots by spiking the soil and the irrigation water with U. An increase in the U level in vegetables has been observed with an increase of U content in the irrigation water and not with soil U. However, the concentration factor for the uptake of U by vegetables decreases with increase of U in water. The study of distribution of U in rice (Oryza saliva) indicates the discrimination of U by different parts of the crop. Among root, stem, and grain, the lowest concentration of U has been observed in grain (rice).     

Uptake of soil nitrogen by soybean as influenced by symbiotic N2-fixation or fertilizer nitrogen supply

Nodulated and N₂-fixing soybean plants (Glycine max. L.) grown in a pot experiment took up significantly more soil N (labelled with ¹⁵N) than non-nodulated control plants. The organic matter in the experimental soil was labelled with ₁₅N during a previous incubation, and the pool of labelled inorganic N originated mainly from mineralization of organic matter. Addition of non-labelled ammonium or nitrate-N to non-nodulated plants did not increase their uptake of labelled soil N. Plants grown with the various N-sources exhausted the soil for KCl-extractable N to almost the same low concentration. Where non-nodulated plants were grown, 60–75% of the inorganic N initially present could be accounted for in plants and KCl-extracts at harvest. An amount corresponding to 98% of the KCl-extractable N initially present was found in nodulated plants and the pool of KCl-extractable N.     

Uptake of aqueous methylmercury by larvalChaoborus americanus

The uptake of monomethylmercury (mmHg) from water by larvalChaoborus americanus was studied. When exposed to aqueous mmHg for 6 days, the pattern of uptake was sigmoidal. The concentration of mmHg in the exposure water, however, was subject to demethylation and volatilization and therefore decreased over time. A model of passive diffusive uptake underestimated the uptake constant while a bioenergetics-based uptake model provided a reasonable estimate. The data suggest that uptake is not merely a passive diffusive process but may be coupled with oxygen uptake.     

Uptake and partitioning of 32P and 65Zn by white clover as affected by eleven isolates of mycorrhizal fungi

We compared the effect of eleven mycorrhizal fungi populations (Glomus spp.) from two different climatic regions (Iran vs. Switzerland) on the uptake and partitioning of ³²P and ⁶⁵Zn by white clover (Trifolium repens L. var. Milkanova). Fungi significantly differed in the colonization of roots with hyphae, vesicles or arbuscules and in their effect on the uptake of ³²P or ⁶⁵Zn by white clover. Fungi also differed in their effects on the percentages of ³²P or ⁶⁵Zn transported to the plant tops. There was no relationship between the uptake of ³²P and that of ⁶⁵Zn in plants colonized by different fungi. Isolates Z7 and Q12 (from Iran) were superior to Swiss isolates for their effect on the uptake of zinc (Zn) by white clover. Among the Swiss isolates, that from Langwiese and Hausweid resulted in the highest and lowest partitioning of both ³²P and ⁶⁵Zn to the plant tops, respectively. We conclude that the effectiveness of vesicular arbuscular mycorrhizae in uptake of phosphorus (P) and Zn may be nutrient specific and that some fungal isolates may also affect the relative partitioning of P and Zn between plant roots and tops.     

Methylmercury production in the anoxic hypolimnion of a Dimictic Seepage Lake

Experimental results and field data indicated that methyl-Hg was produced within a layer of bacterioplankton near the top of the anoxic hypolimnion of Pallette Lake. In situ incubations at ambient Hg concentrations indicated that the net flux of methyl-Hg from the layer was between 50 and 100 pmol/m^2*d. This input was sufficient to account for the summer accumulation of methyl-Hg in the entire hypolimnion and it exceeded atmospheric inputs by 2 orders of magnitude. Maximum rates of net methylation occurred in the same region of the water column where we observed maximum rates of sulfate reduction. The measured rates were: 100 fmol rriethyl-Hg/L^*d and 90 nmol SO₄/L^*d. Sulfate reducing enrichment cultures isolated from the hypolimnion were also able to methylate Hg in the laboratory. Sulfate reduction did not occur in anoxic profundal sediments during summer and we infer from ancillary data that methylation in profundal sediments was also low. Whole-lake rates of sulfate reduction in the hypolimnetic layer and shallow sediments were roughly equivalent, but we cannot yet compare methylation rates at these sites due to large uncertainties in the littoral flux of methyl-Hg. We propose that zones of Hg methylation and SO4 reduction follow the oxic/anoxic boundary in both the watercolumn and sediments. The relative importance of watercolumn and sediment processes will depend on the physical and chemical structure of a given lake.