Concentrations In Plant Organs Research Articles

Bioavailability of metals and As from acidified multicontaminated soils: Use of white lupin to validate several extraction methods

White lupin is an annual crop that has been used for phytostabilization of acidified multicontaminated (heavy metals and As) soils from the Aznalcóllar spill-affected area, Southern Spain. One of the most important factors for successful phytostabilization is monitoring the pollutant bioavailability in the soil. The aim of this work was to determine the best-suited method for assessing the bioavailability of heavy metals together with As in the Aznalcóllar spill-affected area, by means of a systematic comparison between different extraction methods (Ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), CaCl2, NaNO3, BCR, (NH4)2SO4 and rhizo). Both AB-DTPA and the first step of the BCR method were found to be unsuitable for assessing the bioavailability of heavy metals and As to plants growing in acidic soils. However, CaCl2-extractable As, Cu, and Zn and NaNO3-extractable As and Zn were well correlated with their concentrations in plant organs. Rhizo and (NH4)2SO4, with the highest determination coefficients, were the most recommended simple extraction methods to assess the bioavailability of As, Cu, Fe, Mn, and Zn in acidified multicontaminated soils using white lupin as an excluder model plant.

Cadmium and copper toxicity for tomato seedlings

We studied cadmium (Cd) and copper (Cu) toxicity in tomato, their accumulation in plant organs and their ability to induce phytochelatin synthesis. The seedlings were cultivated in nutrient solution supplemented with increased concentrations of CdCl 2 or CuSO 4 from 0 to 50 μM. After 7 days of treatment, plants were harvested and the dry weight, the amount of thiobarbituric acid-reactive substances (TBARS). Cd and Cu contents and SH groups rich peptides were determined. We found that Cd and Cu decrease tomato growth, notably at high Cu levels. Cd and Cu concentrations in plant organs increased with applied amounts. Cd and Cu concentrations were the highest in roots. The amount of thiobarbituric acid-reactive substances, that estimate the lipid peroxidation, was increased with heavy metal exposure and was, mainly, higher in roots with Cu treatment.

Growth and physiological response of tomato plants to different periods of nitrogen starvation and recovery

SummaryYoung, vegetative-state tomato plants, starved of N for 1, 3 or 7 d, followed, in each case, by a 7-d recovery period with nutrient solution containing N, were examined. Relative growth rate (RGR), leaf photosynthesis and leaf expansion were reduced after only 1 d of N starvation. Tissue N concentrations fell during N starvation, the effect being stronger in stems and leaves than in roots, while the growth rate of roots, expressed as a fraction of total plant mass, was less affected than for stems or leaves. Net assimilation rate (NAR) was affected more than leaf area ratio (LAR) in the early stages of N-starvation. During the N starvation period, NO3-N concentrations in plant organs fell quickly and were negligible after 7 d. During the recovery period, the RGR and plant total-N concentration of starved plants were restored to control values. The critical N concentration for optimum growth rate was found to be 3.8%, which was reached before 3 d of N starvation.

Modeling biomass growth, N-uptake and phenological development of potato crop

Using the modeling tool Expert-N, daily fluxes of water, carbon and nitrogen in potato fields were simulated in this study. The crop growth model Soil–Plant–Atmosphere System Simulation (SPASS) was integrated in Expert-N and adapted for the simulation of potato growth. The aim of the study was to investigate the extent to which the SPASS model, tested thus far only for winter wheat, is suitable for the simulation of potato crops. In addition to re-parameterization of the model, minor modifications, such as description of phenological development, assimilate partitioning, nitrogen uptake and leaf senescence were carried out without changing the overall structure of the model. The SPASS model was calibrated using data from a potato field experiment carried out in 1996 at the Research Station Scheyern, which examined the effects of various fertilization applications on the growth and yield of two potato varieties, “Christa” and “Agria”, representing early and late maturity classes, respectively. Distinctions between “Christa” and “Agria” were realized by variable parameter values concerning phenological development, assimilate partitioning and nitrogen concentration in tubers. The model's ability to predict potato yields and nitrogen uptake was compared with actual values obtained in different years at other fields of the Research Station (only “Agria”). Simulation results show that the SPASS model was able to describe the effect of different N fertilizer applications on potato growth and nitrogen uptake. Differences between the two potato varieties could be adequately predicted, and tuber yields and nitrogen uptake well predicted. However, estimated modeling efficiencies suggest that further improvements are due. Crucial components of the model are the control of root nitrogen uptake and the regulation of the distribution of assimilates to different plant organs. To obtain a broader basis for the verification of the corresponding simulation modules, further experiments addressing optimal nitrogen concentrations in plant organs are necessary. Efforts to refine the SPASS model should be concentrated on a dynamical description of the partitioning pattern of assimilates, including a direct response of the partitioning pattern to changing environmental conditions.

Variability of N2-fixation in common bean (Phaseolus vulgaris L.) under P deficiency is related to P use efficiency

Common bean often faces P deficiency in soils where it is generally grown. Such a deficiency is a major limitation to grain yield improvement, especially when common bean relies on N2 fixation. Screening for symbiotic N2 fixation (SNF) under P deficiency (72 μmol P plant-1 week-1) was performed in a glasshouse with 220 lines originating from the Andean and Meso-American gene pools. Large variability in shoot dry weight and SNF under P deficiency was found. SNF tolerance to P deficiency was mostly found among late flowering type IV lines, with the exception of three early flowering type III lines. The SNF tolerance to P deficiency was correlated with: (i) low nodule P concentration in all the growth types, and (ii) intense and early nodulation for type IV lines, or (iii) large root dry weight and high nodule nitrogenase for type III lines. Large genotypic variability for nitrogen use efficiency, i.e. biomass per N concentration was also found. However, the ratio plant N per plant P concentration was the most discriminating. We concluded that this later ratio, which is almost similar to plant N-fixed per plant P concentration, in glasshouse hydroponics culture might be: (i) an estimate of the P use efficiency for SNF, (ii) a consequence of low P concentration in plant organs, especially nodules, and (iii) a determinant of genotypic variability of SNF tolerance to P deficiency.

Root Restriction and Potassium and Calcium Solution Concentrations Affect Dry-matter Production, Cation Uptake, and Blossom-end Rot in Greenhouse Tomato

Root restriction has been reported to reduce fruit yield, the incidence of blossom end rot (BER) and K concentration in tomato (Lycopersicon esculentum L. `F121') plant organs. The objectives of the present work were to study the effect of root restriction, and combination of K and Ca solution concentrations, on greenhouse tomato fruit yield, quality and cation uptake. Root restriction reduced total yield but improved fruit quality by increasing the dry matter concentration and reducing the incidence of BER. Increasing the K concentration from 5.0 to 10 mmol·L-1 reduced the marketable yield, due to increased incidence of BER. Root restriction decreased K concentration and K/Ca ratio in tomato plant organs, but had no effect on K uptake rate per unit root fresh weight. Increasing K concentration from 2.5 to 10 mmol·L-1 increased the K concentration in plant organs and K uptake rate, but reduced that of Ca. In contrast, increasing Ca concentration in the solution had no effect on K concentration in plant organs and K uptake rate. The incidence of BER correlated well with K/Ca concentration ratio in the leaves, whereas a poor correlation was obtained with K/Ca concentration ratio in ripe fruit.

Growth, yield and composition of four winter cereals. II. Nitrogen and carbohydrate economy

A field experiment with 3 cultivars each of wheat, rye, triticale and barley, grown at a density of about 320 plants/m, was conducted in 1986 on a fertile clay soil at East Flevoland, Netherlands. N at 120 kg/ha for wheat and triticale and 60 kg/ha for rye and barley was split-dressed in 2 applications. N yield was highest in wheat (196 kg/ha) and lowest in rye (123 kg/ha). The amounts taken up were influenced by the N rate. The triticale cv. Lasko and the barley cv. Marinka had a higher N-uptake than the other triticale and barley cultivars. N harvest index (i.e. the ratio of N in grains and N in above-ground DM at final harvest) was lowest in rye and highest in barley. N concentration in plant organs (grains, chaff, leaves, stems and roots) was higher in wheat and triticale than in rye and barley. This was probably caused by the difference in the level of N application. N use efficiency, expressed as grain DM production/kg N taken up, was 53 in wheat, 68 in rye, 50 in triticale and 61 in barley. In all species, the largest reserves of water-soluble carbohydrates (WSC) were found in the stems. Rye allocated more dry matter to stem growth before flowering than wheat, triticale and barley. Averaged over these cereals, 26% of WSC, produced before flowering, was used for redistribution and respiration during grain production.

Symbiotic dinitrogen fixation and host‐plant growth during development of and recovery from phosphorus deficiency

Characterization of nodule growth and function, phosphorus and nitrogen status of plant tissues and host‐plant growth of nodulated soybean (Glycine max L. Merr.) plants developing and recovering from phosphorus deficiency was used to evaluate the role of phosphorus in symbiotic dinitrogen fixation. The sequence of physiological responses during recovery from phosphorus deficiency was; (1) rapid uptake of phosphorus, (2) rapid increases in the phosphorus concentration of leaves and nodules, (3) enhanced growth and function of nodules, (4) increased nitrogen concentrations in all plant organs and (5) enhanced plant growth. The sequence of physiological responses to onset of phosphorus deficiency was; (1) decreased phosphorus uptake, (2) decreased phosphorus concentrations in leaves and nodules, (3) decreased nodule function, (4) decreased nitrogen concentration in plant organs and (5) decreased plant growth. These results, in conjunction with previously published data (Sa and Israel, Plant Physiol. 97: 928–935, 1991), support an interpretation that the total response of symbiotic dinitrogen fixation in soybean plants to altered phosphorus supply is a function of both indirect effects on host‐plant growth and more direct effects on the metabolic function of nodules.

Salinity-calcium interactions on growth and ionic concentration of Citrus plants

Two-year-old Navel orange scions (Citrus sinensis (L.) Osbeck) budded to either Cleopatra mandarin (C. reticulata) and Troyer citrange (C. sinensis × P. trifoliata) rootstocks were used in this experiment. Cleopatra manda in rootstock was considered more tolerant to salinity than Troyer citrange, and this property was attributed to a greater capacity to exclude chloride ions. Plants were grown under glasshouse conditions and supplied with nutrient solution containing either no or 45 mM NaCl. Calcium concentration was increased from 3 to 30 mM. Sodium, potassium, calcium and chloride concentrations in plant organs were analyzed after 90 days of treatment. Supplemental Ca was found to mitigate the adverse effects of salinity on plant growth, defoliation or leaf injury. Chemical analysis indicated that in plants grafted on Troyer citrange Ca restricted uptake and subsequent translocation of Na to the leaves and increased K concentration in both roots and leaves. However, in Cleopatra mandarin-grafted plants increasing Ca levels seemed to reduce transport of Na from roots to leaves, and Na accumulation in roots was associated with reduced concentration of K in this rootstock. Organ chloride analysis showed that Cl accumulation in leaves of plants grafted on both rootstocks was reduced when external Ca concentration increased, whereas Cl concentration in roots remained constant or increased. The data of distribution of Cl in plants showed that a high external Ca level increased Cl accumulation in the basal stem and roots, and reduced the transport of Cl from roots to leaves.

Pepper Seedling Response to Steady and Transient Nitrogen and Phosphorus Supply

AbstractUsing transplants for growing pepper (Capsicum annuum L.) is widespread, but little is known about seedling response to transient N and P supply during tbe nursery growth stage. The objective of this work was to study the effect of steady and alternating N and P concentrations in solution culture on pepper seedling development, dry‐matter production rate, and N and P uptake rates, to allow better control of production by transplants. Seedlings were grown in trays of pyramidal cells, packed with vermiculite and floated on well‐aerated nutrient solutions of high (6 mM) or low (1 mM) N and high (0.25 mM) or low (0.01 or 0.03 mM) P. Dry‐matter accumulation in seedling tops as a function of time conformed in all treatments to a first‐order exponential equation. The growth rate constant was significantly higher in the high than in the low N or P concentrations. Root growth rate was less affected by the N and P solution concentration than was the top growth rate. Five‐day‐long alternations of solution concentration from high to low and from low to high N and P significantly changed dry‐matter production rate and nutrient content in plants. Growth and uptake rates regained their original values when seedlings were re‐exposed for 5 d to the original solutions. The rapid changes in growth rate were attributed to rapid variations in the flux of N and P uptake in response to changes in solution concentrations, which affected N and P concentration in plant organs. Varying N and P concentrations in tops affected dry‐matter production rate, whereas variations in N and P concentrations in roots influenced the flux of uptake of P and N, respectively.

Temporal variation of metal concentrations in biogeochemical samples over the Royal Tiger Mine, Colorado, Part II. Between-year variation

Samples of lodgepole pine (Pinus contorta Dougl. ex Loud.) were collected every two months for six sampling periods, May 1983 to March 1984. Needle, twig, and wood samples were taken at sixty-five points at 15-m intervals along a 1-km transect line and analyzed for Cu, Zn, Pb, Mo, Au, and Ag. The study area was the Royal Tiger Mine in the Breckenridge Mining District of Colorado, U.S.A. The mine workings were located within a fault-bounded breccia complex which is well mineralized with Cu, Pb, Zn, Au, Ag, and Bi. The sample transect line extended over the complex into unmineralized areas. The mine workings provided underground geologic control. Wood and ashed needle and twig samples over the mineralized area showed significant variation in Au concentrations. In the 12-month study period, wood samples ranged from <0.1 ppb to 35.0 ppb Au, whereas, needle and twig samples ranged from <0.1 ppb to 300 and 900 ppb Au, respectively. Higher Au concentrations occurred in the spring and early summer. Gold anomalies, as measured by Au concentrations in plant organs, were observed in less than half the sampling periods. Gold concentrations in needles were consistently lower, but paralleled Au concentrations in the twigs. Copper concentrations ranged from <0.5 to 8 ppm in wood; up to 191 ppm in needles, and up to 353 ppm in twigs. Mineralized areas were identified by high Cu concentrations in needle and twig samples over all sampling periods. Concentrations of Zn in wood ranged from 3 to 55 ppm and identified background/anomaly contrasts and zones of mineralization, although the concentrations varied over time. Zn concentrations in needles and twigs of up to 7,420 ppm indicated background/anomaly contrasts without variation of peak concentrations. Molybdenum concentrations in wood were mostly below detection limits and not indicative of mineralization. Mean Mo concentrations of 4.7 and 13 ppm in needles and twigs did not identify any background/anomaly contrasts. Similarly, Ag concentrations were frequently below detection limits and were not useful for mineralization identification.

Temporal variation of metal concentrations in biogeochemical samples over the Royal Tiger Mine, Colorado, part I: Within year variation

Samples of lodgepole pine ( Pinus contorta Dougl. ex Loud.) were collected every two months for six sampling periods, May 1983 to March 1984. Needle, twig, and wood samples were taken at sixty-five points at 15-m intervals along a 1-km transect line and analyzed for Cu, Zn, Pb, Mo, Au, and Ag. The study area was the Royal Tiger Mine in the Breckenridge Mining District of Colorado, U.S.A. The mine workings were located within a fault-bounded breccia complex which is well mineralized with Cu, Pb, Zn, Au, Ag, and Bi. The sample transect line extended over the complex into unmineralized areas. The mine workings provided underground geologic control. Wood and ashed needle and twig samples over the mineralized area showed significant variation in Au concentrations. In the 12-month study period, wood samples ranged from <0.1 ppb to 35.0 ppb Au, whereas, needle and twig samples ranged from <0.1 ppb to 300 and 900 ppb Au, respectively. Higher Au concentrations occurred in the spring and early summer. Gold anomalies, as measured by Au concentrations in plant organs, were observed in less than half the sampling periods. Gold concentrations in needles were consistently lower, but paralleled Au concentrations in the twigs. Copper concentrations ranged from <0.5 to 8 ppm in wood; up to 191 ppm in needles, and up to 353 ppm in twigs. Mineralized areas were identified by high Cu concentrations in needle and twig samples over all sampling periods. Concentrations of Zn in wood ranged from 3 to 55 ppm and identified background/anomaly contrasts and zones of mineralization, although the concentrations varied over time. Zn concentrations in needles and twigs of up to 7,420 ppm indicated background/anomaly contrasts without variation of peak concentrations. Molybdenum concentrations in wood were mostly below detection limits and not indicative of mineralization. Mean Mo concentrations of 4.7 and 13 ppm in needles and twigs did not identify any background/anomaly contrasts. Similarly, Ag concentrations were frequently below detection limits and were not useful for mineralization identification.