Absorption of HCO3 ‐ by roots and its effect on carbon metabolism of tomato

Six‐week old seedlings of tomato [Lycopersicon esculentum) were placed in growth chambers, hypocotyl and the root system (in the lower part of the chamber) being precisely separated from the stem (the upper part of the chamber). The composition of the medium was modified by enriching it with KHCO₃ (converted to the value of about 0.1% CO₂ concentration) or additionally with ¹⁴C. The total radioactivity associated with roots, shoots, and leaves after 72 h chase period was determined. About 61% of the total radioactivity were found in root and 39% in shoots and leaves. Differences in the concentration of HCOâ in the medium significantly modified the concentration of malic acid (MA) in the tissues. An increase in KHCO₃ concentration in the medium to the level equivalent to about 0.1% CO₂ raised the level of MA by about 854%, 150%, and 134% in root, shoot, and leaf, respectively, in relation to the control (without KHCO₃). The occurrence of phosphoenolpyruvate carboxylase (E.C. 4.1.1.31) was found in longitudinal‐sections of roots, using immunofluorescent technique method. The obtained results confirm a significant role of absorption of CO₂ forms dissolved in the medium, by roots and also of the massive transport of carbon compounds from roots to shoot and leaves. The results also suggest that this kind of root absorption might play an important role as an alternative source of CO₂ besides the photosynthetic carboxylation of CO₂ from atmospheric air.     

Light‐induced reduction of FE3+ as related to causes of chlorosis in cotton

In growth chambers, cotton (Gossypium hirsutum L. genetic selection ‘M8') was grown in a synthetic growth medium under four light regimes: low pressure sodium (LPS), LPS + Incandescent (Inc), cool white fluorescent (CWF) and CWF + Inc lamps at 22 C under LPS lamps. Less chlorosis developed at 26 C than at 22 C and less under LPS + Inc than under LPS lamps. All plants were green under CWF and CWF + Inc light. Green and chlorotic plant tissue contained about the same concentrations of Fe. The proposed hypothesis was that chlorotic tissue’ contained less Fe²⁺ than green tissue. Chlorotic leaves treated with FeSO₄ turned a green color. Enough CWF + Inc light passed through an intact leaf to reduce Fe³⁺ to Fe²⁺ in vitro. Also in vitro, Fe³⁺ was reduced by CWF, by Inc, but not by LPS light. The amount of Fe³⁺ reduced during an illumination period was directly proportional to the quantity of light used. In vitro, citrate and malate enhanced Fe³⁺ reduction, whereas phosphate, pyrophosphate, OH^‐, Cu²⁺, Ni²⁺, Mn²⁺, Zn²⁺, and F^‐ all inhibited Fe³⁺ reduction by light. Orthophosphate was about 8 times as effective as organic P in decreasing Fe³⁺ reduction. Citrate largely alleviated the inhibitory effects of Pi and pH (up to pH 6). The data also provide a possible explanation of a role for many of the elements known to induce or aggravate Fe chlorosis (inhibit Fe³⁺ reduction). Quantity and quality of light apparently play key roles in plant growth as related to reduction of Fe³⁺ to Fe²⁺ in plant tops.     

Seasonal variation in carbon isotopic composition of bog plant litter during 3 years of field decomposition

In this study, we describe the seasonal variation in ¹³C abundance in the litter of two Sphagnum species and four vascular plant species during 3 years of field decomposition in an Italian alpine bog. Litter bags were periodically retrieved at the end of summer and winter periods, and the δ¹³C in residual litter was related to mass loss, litter chemistry, and climatic conditions. In Sphagnum litter, higher rates of decomposition during summer months were associated with an increase of δ¹³C probably due to the incorporation of microbial organic compounds rich in ¹³C in the residual litter. In the litter of Eriophorum vaginatum, Carex rostrata and Calluna vulgaris, we observed a decrease of δ¹³C with an increase in the concentration of lignin-like compounds. The residual litter of Potentilla erecta showed a decrease of ¹³C abundance during the first 2 years, but on proceeding the decomposition, the δ¹³C increased again probably reflecting the incorporation of microbial organic compounds.     

Seasonal variation in nitrogen isotopic composition of bog plant litter during 3 years of field decomposition

In this study, we describe the seasonal variation in ¹⁵N abundance in the litter of two Sphagnum species and four vascular plant species during 3 years of field decomposition in an Italian Alpine bog. Litter bags were periodically retrieved at the end of summer and winter periods, and the δ¹⁵N in residual litter was related to mass loss, litter chemistry, and climatic conditions. In Sphagnum litter, higher rates of decomposition during summer months were associated with an increase of δ¹⁵N probably due to the incorporation of microbial organic compounds rich in ¹⁵N. The litter of Eriophorum vaginatum and Carex rostrata was characterized by a decrease of δ¹⁵N, so that the final signature was significantly lower than in initial litter. On the other hand, the residual litter of Potentilla erecta and Calluna vulgaris was characterized by a final δ¹⁵N higher than in initial litter. Our data reported a seasonality of ¹⁵N abundance in the residual litter of Sphagnum species, but not in that of vascular plant species, thus highlighting the role of differences in litter chemistry.     

Effects of Soil Texture and CaCO3 on Turnover of Organic Material in Chao Soils

Decomposition experiments of ^14C-labelled sickle alfalfa in chao soils of different texture and these soils after removal of CaCO3 were carried out under field and laboratory conditions respectively.The amount of residual ^14C in,or ^14CO2 evolved from,the soils at intervals after the beginning of devomposition were measured and the distribution of native and labelled C between particle size fractions isolated from these soils was edtermined.Results showed that contents of both labelled (^14C) and non-labelled (^12C) carbon decreased with increasing particle size.The enrichment factor for ^14C was higher than that for ^12C in the clay fraction,the reverse being true for the silt enrichment factors.The effect of soil texture on the decomposition of plant material could not be observed in chao soils when the clay content was lower than 270g kg^-1,while it became obvious once CaCO3 was removed was correlated from these soils.The decomposition rate of plant material in the soil from which the native CaCO3 Was removed was correlated significantly to both the clay content of the soil and the application rate of CaCO3.A preliminary correction equation describing the effect of clay and CaCO3 on the decomposition of organic material in chao soil was derived from the results obtained.     

Expression of the Truncated vip3A Gene at the 3'-terminus from Bacillus thuringiensis in Escherichia coli

将苏云金芽孢杆菌(Bacillus thuringiensis)缺失C端154个氨基酸编码区的vip3A基因(vip3T)插入原核表达载体pQE30，构建了重组表达载体pQEvip3T，并转化大肠杆菌(Escherichia coli ) M15进行IPTG诱导表达，比较了完整的Vip3A蛋白和C端缺失的蛋白Vip3T的可溶性和杀虫活性。与Vip3A不同，融合蛋白Vip3T以不可溶的包含体形式存在，诱导表达的菌液中没有检测到可溶性Vip3T蛋白。生物测定结果表明，M15(pOTP)诱导表达的Vip3A蛋白对初孵斜纹夜蛾(Spodoptera litua)和甜菜夜蛾(S. exigua)幼虫具有较高的杀虫活性，其提纯的包含体无毒，但包含体的碱性裂解液却又恢复了对夜蛾科害虫的活性；M15(pQEvip3T)菌液、包含体及其碱性裂解液对这两种昆虫幼虫则完全无毒，说明在大肠杆菌中，Vip3A蛋白C端氨基酸可能对Vip3A蛋白的可溶性和杀虫活性具有重要的影响。     

Influence of ambient acidity on the absorption of NO3 − and NH4 + by tomato punts

Abstract

The effects of ambient acidity on NO₃ ^? and Nh₄ ⁺ absorption by 26‐day‐old tomato plants (Lycopersicon esculentum Mill.) were examined in solution culture. The absorption rate per unit root mass was measured for 6 hr. The NO₃ ^? absorption rate from 0.4 mM NaNO, was 36% greater at pH 4.5 than at pH 6.5. In contrast, the NhY absorption rate was approximately 42% greater at pH 5.5 or 6.5 than at pH 4.5. The presence of equimolar NHr from 0.4 mM NH^NO, decreased the NO, absorption rate at pH 5.5 or 6.5 but did not reduce the rate at pH 4.5. The NO, absorption rate was inhibited less at pH 5.5 when equimolar NHr was supplied from 0.2 mM (NH₄)₂S0₄ as opposed to NH₄NO₃. At pH 5.5, the N0₃ ^? absorption rate increased with increased #OPNH₄#CP₂SO₄ concentration. The presence of equimolar NO₃ ^? supplied as either NaNO₃ or NH₄NO₃ had no effect on the NH₄ ⁺ absorption rate at pH 5.5 or 6.5. However, at pH 4.5, the NH₄ ⁺ absorption rate was slightly reduced from NH₄NO₃ solutions relative to that from a (NH₄)₂S0₄ solution.     

Application of “Four-Plane Model” to the Adsorption of K+, NO3 -, and SO4 2- from a Mixed Solution of KNO3 and K2SO4 on Andisols

To evaluate the interaction between anionic species when they were adsorbed on variable charge soils, we measured the adsorption of NO₃ ^- and SO₄ ^2- on. an Andisol equilibrated with a mixture of KNO₃ and K₂SO₄ solutions. The amount of NO₃ ^- adsorption declined with the increase in the concentration of SO₄ ^2-. On the other hand, the amount of SO₄ ^2- adsorption increased with the increase in the concentration of NO₃ ^-. These phenomena can not be explained by the simple “exchange theory” or the “Three-plane model” unless surface complexation is associated with the changes in the electrical potential of the surface. Therefore, in order to explain the phenomena by using the “Four-plane model” with surface complexation, a new equation was derived for the Diffuse Double Layer (DDL) charge from the “main equation of DDL theory” (equation of electrical potential in DDL) instead of the “Gouy-Chapman equation,” which can be used only for single symmetric electrolytes but nor for a mixture. By introducing the new equation to the computer program for analyzing the Four-plane model, the interaction between anionic species adsorbed on Andisols could be explained well. It was considered that SO₄ ^2- acted as a regulator for the ionic concentration, osmotic pressure and pH of the soil solution, and consequently, these factors affected the vertical distribution and mobility of anionic species and also the mobility of counter-ions in Andisols.     

Growth of tomato seedlings under different HCO‐ 3 concentration in the medium

An increase in the concentration of HCO^‐ ₃ ions in liquid media surrounding the root system significantly affected the biomass production of tomato seedlings in early stages of growth. This effect depended upon HCO^‐ ₃ concentration. The cultivation of seedlings during a period of 24 days (from 21–45 days after sowing) on a medium enriched to 5.68 mM HCO₃ (0.025% CO₂ after the computed dissociation) increased the production of dry matter (DW) plant"¹ to about 179% as compared with the respective control. Various tomato organs showed different values of DW increase, the greatest one being noted in leaf blades. This result was correlated with an increase in leaf blade area to about 176% in relation to the control. With an increase in the concentration to 22.72 mM HCO^‐ ₃ (0.1% CO₂ after the computed dissociation) a general tendency of changes was maintained, however, the absolute values of growth were diminished. In media of an enriched HCO₃ content the length of shoots, and roots, was not significantly modified. The values of other growth parameters computed for the respective three experimental series with HCO₃ concentration of 0.0, 5.68, and 22.72 mM, respectively, in the medium also showed correlations with the biomass production in tomato organs. The enrichment of liquid media with HCO₃ affected the processes of absorption, distribution, and accumulation of such elements as nitrogen, potassium, and calcium. No statistically significant differences in the content of phosphorus were obtained. The data presented here are the continuation of the study whose results were published in 1992 (J. Plant Nutr. 15: 293–312).     

Diurnal variations in uptake,transport and assimilation of NO3 ‐and efflux of OH‐ in maize plants

Maize plants, grown for 7 and 21 days on a nutrient solution with NO₃ ^‐ as the sole nitrogen source showed a clear diurnal pattern with respect to the in vivo NRA. Especially in roots dark/light fluctuations of the enzyme activity were high. Also in NO₃ ^‐ uptake, OH^‐ efflux and endogenous content of water soluble carbohydrates a diurnal variation was found. The plant age did not significantly affect the daily rhythm.

Because day/night changes of the in vivo root NRA and nitrate uptake were proportional, the relative content of reduced N in the xylem sap of the plants was constant during a day/night interval. At both day 7 and day 21 about 40–50% of the N was transported via the xylem as amino N. As a result of non‐synchronous variation of the specific root and shoot NRA, root reduction capacity showed a great within‐day variation. It varied between 20 and 40% of the whole plant reduction capacity. Since the ratio N‐organic to N‐total in the xylem sap was about 0.5, cycling of organic nitrogen was very likely in these maize plants.     

Application of a rice husk-derived biochar in soil immobilization of iodide (I−) and iodate (IO3 −)

Journal of Soils and Sediments - Radioiodine is an inevitable product of nuclear fission during nuclear fuel reprocessing and nuclear accident and finally is brought back to surface soil by...     

Use of NH4 HCO3‐DTPA soil test to assess availability and toxicity of selenium to alfalfa plants

Abstract

This study was carried out to determine if ammonium bicarbonate‐DTPA soil test (AB‐DTPA) of Soltanpour and Schwab for simultaneous extraction of P, K, Zn, Fe, Cu and Mn can be used to determine the availability index for Se. Five Mollisols from North Dakota were treated with sodium selenate and were subjected to several wetting and drying cycles. These soils were extracted with hot water and with ammonium bicarbonate‐DTPA (AB‐DTPA) solution for Se analysis. Alfalfa plants were grown in these soils in a growth chamber to determine plant uptake of Se. In addition to the above experiment, coal mine soil and overburden materials from Western Colorado were extracted and analyzed as mentioned above.

It was found that hot water and AB‐DTPA extracted approximately equal amounts of Se from Mollisols. A high degree of correlation (r =0.96) was found between Se uptake by plants and AB‐DTPA extractable Se. Extractable level of Se in treated soils was decreased with time due to change of selenate to less soluble Se forms and plant uptake of Se. An AB‐DTPA extractable Se level of over 100 ppb produced alfalfa plants containing 5 ppm or higher levels of Se that can be considered toxic to animals. Soils with about 2000 ppb of extractable Se were highly toxic to alfalfa plants and resulted in plant concentrations of over 1000 ppm of Se. The high rate of selenate (4ppm Se) was less toxic to alfalfa plants in soils of high organic matter content. This lower toxicity was accompanied with lower extractable levels of Se.

The AB‐DTPA solution extracted on the average about 31% more Se than hot water from the mine and overburden samples and was highly correlated with the latter (r =0.92). The results indicated the presence of bicarbonate‐exchangeable Se in these materials.     

Identification of cyanidin 3-O-β-(6″-(3-hydroxy-3-methylglutaroyl)glucoside) and other anthocyanins from wild and cultivated blackberries

Anthocyanins from blackberries are natural dietary pigments. The aim of this study was to investigate the occurrence of anthocyanins in fruits of wild Norwegian blackberries and three blackberry ( Rubus fruticosus L.) cultivars and to report the complete identification of cyanidin 3-O-β-(6″-(3-hydroxy-3-methylglutaroyl)glucopyranoside), 5. This new pigment is most probably the same pigment that has previously been reported to occur in various blackberry samples as cyanidin 3-dioxalylglucoside. All of the examined blackberry samples contained in similar relative proportions the 3-glucoside (1), 3-rutinoside (2), 3-xyloside (3), and 3-O-β-(6″-malonylglucoside) (4) of cyanidin and 5. The absolute amounts of 1-5 in the wild Norwegian blackberries were 249, 18, 10, 24, and 22 mg of cyanidin 3-glucoside equivalents/100 g of fresh weight, respectively.     

The role of free space calcium in the basipetal transport of indole‐3‐acetic acid in sunflower hypocotyls 1

Calcium has been reported to be involved in the basipetal transport of indole‐3‐acetic acid (IAA). It has been suggested that basipetal transport of IAA requires the influx of Ca²⁺ into the cytoplasm from the cell wall free space and that Ca²⁺ acts as a second messenger. Experiments were conducted to determine the interaction of free space Ca²⁺ with the basipetal transport of IAA. Four day old sunflower (Helianthus annus L. cv ‘Russian Mammoth') seedlings grown in 0.20 strength Hoagland's solution were either left intact or excised below the cotyledonary node to remove the meristem, the source of IAA in the shoot. After removal of the node, the plants were treated with or without 500 μM IAA in lanolin paste. After 24 h, 3 mm segments were cut from the hypocotyls and incubated in KCl. Solution Ca²⁺ concentration, representing free space Ca²⁺, increased when the source of IAA was removed. Plants which were provided a source of IAA, either endogenously or exogenously, had low levels of free space Ca²⁺. In a separate experiment, segments of sunflower hypocotyls were incubated in KCl solutions with or without 10 μM IAA. Free space Ca²⁺ was lower when the segments were incubated in solutions containing IAA. It was concluded that basipetal IAA transport resulted in low levels of Ca²⁺ in the free space, which supports the hypothesis that basipetal IAA transport has a requirement for the influx of Ca²⁺ from the free space into the cytoplasm.     

Application of NaHCO3/ DTPA Extractant-ICP Spectrometry Technique in Soil Test for Availability of Nutrients and Heavy Metals

Soil test for availability of nutrients and heavy metals is extensively served as a means for the evaluations of soil fertility, and environmental effects and phytotoxicity of pollutants in soils, and for the fertilizer recommendation in agricultural and environmental sciences. Therefore, great attention has been paid to the measurement of elemental availability in soil test.     

Zinc nutrition and levels of endogenous lndole‐3‐acetic acid in radish shoots

Radish (Raphanus sativus cv. Akamaru‐Hatsukadaikon) was grown for several experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of radish shoots were observed. Two‐dimensional thin layer chromatography (TLC) and gas chromatography‐mass spectrometry (GC‐MS) analysis revealed the presence of endogenous indole‐3‐acetic acid (IAA) in Zn‐deficient radish shoots. An estimate has been made of alkali‐labile (1 and 7N NaOH) IAA in Zn‐deficient radish shoots with the use of gas chromatography (GC). The level of 7N NaOH‐labile IAA (peptidic + ester + free) and IN NaOH‐labile IAA (ester + free) in Zn‐deficient radish shoots was almost the same as that of control radish shoots. These results suggest that Zn nutrition did not affect the level of endogenous IAA in radish shoots.     

Potential use of karanjin (3-methoxy furano-2′,3′,7,8-flavone) as a nitrification inhibitor in different soil types

Karanjin, a furanoflavonoid (3-methoxy furano –?2 ′ , 3 ′ , 7, 8-flavone), is obtained from the seeds of karanja tree (Pongamia glabra Vent.), which is reported to have nitrification inhibitory properties but has been tested in few soil types. Efficiency of karanjin as a nitrification inhibitor in seven different soils of India was tested in a laboratory incubation study. The soils (800?g) were adjusted to field capacity moisture content, fertilized with urea and urea combined with karanjin at a rate of 20% of applied urea-N (100?mg?kg^???1 soil) and incubated at 35°C for a period of 7 weeks, during which urea [CO(NH₂)₂], ammonium (NH₄ ^?+?), nitrite (NO₂ ^???) and nitrate (NO₃ ^???) content in the soils was measured periodically and nitrification inhibition at different stages was calculated. Urea hydrolysis was almost complete within 72?h of application in all the soils and was not affected by karanjin. Karanjin had conserved ammonium in all the soils at all stages and nitrate formation was effectively minimized. Nitrite in soils was short-lived and low. Nitrification inhibition by karanjin remained high for a period of approximately 6 weeks, decreased with time and ranged from 9?–?76% for all the soils. The study shows that this plant product can be an effective nitrification inhibitor in several types of soil.