Mg In Roots Research Articles

Nutrimental modifications in blueberry (Vaccinium corymbosum L.) caused by vanadium supply

Blueberry plants prosper in acid environments with pH 4.5, condition that enhances vanadium (V) bioavailability. In different species, literature reports nutrimental modifications caused by V, nevertheless in blueberry plants this effect remains unknown. This study assessed the impact of six vanadium (V) doses in nutrient solutions (0, 20, 40, 80, 160 µM) and as foliar sprays (20 µM) on blueberry plants, employing a completely randomized experimental design with three replicates. At 66 days after applying the treatments, nutriments concentrations in leaves, stems and roots of each plant were determinate. Except for N, V modified nutrimental concentrations in at least one plant organ. V applied to foliage benefits Mn (67%) in leaf, as Ca (56%), Mg (40%), B (26%) and Mn (46%) did in stems and P (50%) in roots. No matter V concentration in solution, P (51%), Fe (270%) and Cu (230%) in roots are enhanced, but Mo it is reduced up to 6 times. The use of 160 µM of V in solutions increases Mg (40%) concentrations in stems, the same happened in Ca (32%) and Zn (47%) in roots but reduced K (35%) in this organ. V applied from 0 to 160 µM in solution increases 3, 64, 225 times V concentration in leaf, stem and roots respectively. These results show that V applications in solution benefits P levels in leaf, Ca and Mg in stem, P, Ca and Mg in root; while foliar spray enhances K, Ca, Mg concentration in stem and Mg in root.

Regulation of magnesium and calcium homeostasis in citrus seedlings under varying magnesium supply

Magnesium (Mg) and calcium (Ca) are two essential macronutrients in plants; however, the characteristics of Mg and Ca concentrations in organ, subcellular and chemical forms and their relationships in citrus plants, especially under varying Mg supply, are not well understood. In this study, Citrus sinensis seedlings (cv. Xuegan) were cultivated in conditions of Mg deficiency (0 mmol Mg2+ L−1) and Mg sufficiency (2 mmol Mg2+ L−1) to investigate the responses of Mg and Ca homeostasis in different organs and fractions. Compared with Mg sufficiency, Mg deficiency significantly decreased root and shoot growth, with the shoot biomass reduction of branch organs was greater than that of parent organs. In addition to increasing the Ca concentration in the parent stem and lateral root organs, Mg deficiency significantly decreased the concentrations and accumulations of Mg and Ca in citrus seedlings, further altering their distribution in different organs. More than 50% of Ca and Mg were sequestrated in the cell wall and soluble fractions, respectively, with Mg concentration decreasing by 15.4% in roots and 46.9% in leaves under Mg deficiency, while Ca concentration decreased by 27.6% in roots and increased by 23.6% in parent leaves. Approximately 90% of Mg exists in inorganic, water-soluble, and pectate and protein-bound forms, and nearly 90% of Ca exists in water-soluble, pectate and protein-bound, phosphate and oxalate acid forms. Except for the decreased inorganic Mg in roots and water-soluble Mg and Ca in leaves, Mg deficiency increased the proportions of Mg and Ca in all chemical forms. However, Mg deficiency generally increased the Ca/Mg ratio in various organs, subcellular and chemical forms, with negative relationships between Mg concentration and Ca/Mg ratio, and the variations of Mg and Ca were highly separated between Mg supply and organs. In conclusion, our results provide insights into the effects of Mg supply on Mg and Ca homeostasis in citrus plants.

Enhancement phenolic content in callus of Taraxacum officinale plant by using phenylalanine precursors

Dandelion (Taraxacum officinale) has been used in traditional medicine. It has been utilized as a source for bioactive compounds. Such as phenolic compounds. Thus, this study aimed to increase phenolic yield in callus cultures supplied with Phenylalanine (Phe.) as a precursor. Seeds of T. officinale were sterilized and cultured in vitro on Murashige and Skoog (MS) medium then used as a source of explants. Leaves and roots were cultured on MS medium supplemented with combinations (0.25, 0.5 or 0.75mg/L) of benzyl adenine purine (BAP) and (1, 2 or 3 mg/L) of indole acetic acid (IAA). The best fresh weight for callus formation was achieved at 0.75 mg/L BAP for leaves and 0.75 mg/L with 2 mg/L IAA for root. Quantitative analyses with spectrophotometer, the total phenols were expressed as Gallic acid standard curve showed phenolic content presence in leaves 15.38 mg and 14.89 mg in root of intact plant. The addition of different concentrations of Phe (0.3, 0.5, 0.7, 0.9, 1 or 1.5 mg/L) as a precursor to the medium led to increase the levels of phenolic content in leaves and roots callus tissue. Phe. at concentration 1.5mg/L enhanced production of phenols to 17.86 mg on leaves callus and 1mg/L concentration of Phe. Enhanced production of phenols to 16.50 mg on roots callus comparison with intact plant. In contrast, even the control treatment (0 mg/ L) concentration of (Phe.) was found to be stimulated phenolic yield in comparison with phenolic content in intact plant.

Distribution of macro- and micronutrients in leaves, roots, and scapes of gerbera affected by calcium and humic acid

Different levels of humic acid (HA) (0, 100, 500, and 1000 mg L−1) and Ca (3.5 and 7 meq/L) were applied to growth media. A multi-level factorial experiment with a completely randomized design was employed with three replicates to evaluate interaction effects. Macro- and micro-nutrient contents were measured in leaves, roots, and scapes of gerbera. Five hundred mg/L HA increased macro- and micronutrients (P, N, K, Mg, Ca, Fe, and Zn) contents of leaves, roots, and scapes. High HA levels reduced some nutrient contents. The 7 meq/L Ca significantly increased Fe and Zn contents of leaves and roots and K and Mg contents of roots, and had no significant effect on other macronutrients. The results showed the importance of Ca-HA treatment in gerbera cultivation through increasing nutrient concentration. The Ca-HA treatment exhibited significant effects on nutrient uptake of gerbera. Ca and HA combination was more effective, especially with 7 meq Ca and 500 mg/L HA, than the low Ca and HA content. The 7 meq/L Ca and 500 mg/L HA increased N, Ca, K, and Zn concentrations in leaves, and Ca, P, Mg, Fe, and Zn concentrations in scapes, and Zn in roots, whereas this trend for Fe, Mg, and N in leaves and P and Mg in roots was found in 100 and 1000 mg/L HA. Conclusively, nutrients’ absorbtion and accumulations in scape and leaves were higher than in roots and were higher when Ca was applied in 7 meq/L with HA at 500 mg/L to gerbera.

Improving Water Efficiency, Nutrients Utilization, and Maize Yield using Super Absorbent Polymers Combined with NPK during Water Deficit Conditions

Background: The increasing global population poses a significant challenge, resulting in a scarcity of food resources on a global scale. Addressing this issue necessitates advancements in agricultural practices, particularly in drought-prone areas. Super absorbent polymers (SAPs) are crucial in improving crop production's water and nutrient utilization efficiency, making them highly relevant for drought-affected areas. Thus, this research aimed to assess the impact of SAPs, combined with manure and fertilizers, on the growth of maize (Zea mays) cv. Ts-1004. Material and Methods: The experiment consisted of nine treatment groups, namely, T1 (Nitrogen, N), T2 (Potassium, K), T3 (Phosphorus, P), T4 (NPK), T5 (Compost), T6 (SAPs), T7 (NPK + Compost), T8 (NPK + SAPs), and T9 (Control). These treatments were evaluated under two water level conditions: well-watered (W1) and water-stressed (W2) in a greenhouse environment. The plants were subjected to water stress by maintaining soil moisture content at 20 – 25% during the knee height and flowering stages for 8 days. Results: The results revealed that significantly (P < 0.05) higher values in ear girth, ear length, number of seeds per ear, and ear weight were observed in the T8 treatment compared to other treatments. Additionally, the T8 treatment exhibited the highest yield under well-watered and water-stressed conditions (3,274.4 kg/ha). The application of SAPs improved soil moisture content, leading to enhanced water use efficiency (24.53 kg/ha/mm) and harvest index. Moreover, SAPs positively influenced the concentration percentage of N, P, K, Ca, and Mg in roots, stems, leaves, and seeds, with T8 showing the highest values under water stress conditions. Conclusion: These findings highlighted the effectiveness of SAPs in enhancing crop growth and productivity, particularly under water stress conditions. This approach will help farmers reduce water stress on crops.

Short-term exposure to elevated CO2 stimulates growth and metabolic responses that alleviate early-stage iron deficiency symptoms in soybean

ABSTRACT Elevated CO2 (eCO2) increase plant biomass and might lead to nutritional losses. The results showed that eCO2 under Fe-deficiency stimulates root dry weight from 0.37–0.80 g plant−1 and shoot dry weight from 0.82–2.10 g plant−1, without compromising root/shoot ratio. Besides, eCO2 improved the chlorophyl content of Fe-deficient plants. However, downregulation of photosynthesis, reduction in stomatal conductance and transpiration rate, and an increase in water-use efficiency was observed due to eCO2. Moreover, under Fe-deficiency, eCO2 decreased K and Mg in roots, and Mg in leaves, whereas increased P and Zn in roots and leaves. In Fe-sufficient plants, eCO2 increased K, P, Mn, Zn and Fe in leaves and did not change the concentration in roots. The Fe-deficiency-induced responses in roots, including the increase in FCR activity, and the expression of Fe-uptake genes were stimulated by eCO2, but were not sufficient to increase Fe concentration in Fe-deficient plants.

Regulating effects of silicon on Cd-accumulation and stress-resistant responding in rice seedling.

Silicon (Si) application could significantly alleviate the toxic effects of cadmium (Cd) on the growth and development of rice. Here, we examined the regulatory effects of Si on Cd accumulation and stress response in rice seedlings through a hydroponic root separation test. The results showed that the biomass of rice seedlings decreased significantly under Cd stress, while the addition of Si could alleviate such negative effect. The uptake, transfer, and accumulation of Cd in rice seedling were significantly affected by Si addition under Cd stress. Si application under the unilateral Cd stress (Si-Cd+Si, Si-Cd) increased Cd-retention coefficient of root by 83.3%-83.6%, which restricted the transfer of Cd from root to aboveground. However, the treatment with Si added to the non-stressed side (Si-Cd) elevated the uptake and accumulation of Cd in rice seedling, with the accumulation in root being increased by 48.2% when compared to the treatment under the unilateral Cd stress without the addition of Si (CK-Cd). The treatment with Si added in two sides (Si-Cd+Si) decreased the uptake of Cd both in root and aboveground parts by 36.7% and 54.9%, respectively. The addition of Si under bilateral Cd stress (Cd-Cd+Si) significantly reduced the Cd uptake of both the root and aboveground parts by 57.8% and 46.5%, respectively, compared to the treatment of bilateral Cd stress (Cd-Cd). Higher Si concentration in rice seedling was found under the Cd stress. More Si was accumulated in rice seedling to resist the Cd stress when Si was added. The addition of Si affected the absorption of other metal elements in rice seedlings, including calcium (Ca), magnesium (Mg) and manganese (Mn). The concentrations of Ca and Mg in root and aboveground parts were significantly increased by Si addition under bilateral Cd-stress (Cd-Cd+Si), but Mn concentration was changed with the stress degree of Cd. The activities of superoxide dismutase (SOD) and peroxidase (POD) in root were affected by Si under Cd stress, especially for the Si-Cd treatment. The activity of POD in the root of the Cd-stress side and that of SOD in non-stress side were significantly increased, which benefit to scavenging the free radicals induced by Cd stress. In conclusion, Si could regulate the growth of rice seedlings, the uptake of elements such as Cd and Si, and the antioxidant reaction of the root system under the Cd stress. High Si concentration in plant is conducive to enhancing Cd tolerance.

Time course of physiological responses in kiwifruit induced by bicarbonate

KEY MESSAGE: Ionic imbalance is one adaptive strategy of kiwifruit to bicarbonate, as indicated mainly by NH₄⁺ accumulation and increased NH₄⁺/NO₃⁻ in bicarbonate-treated roots as well as decreased NH₄⁺/NO₃⁻ in bicarbonate-treated leaves. Bicarbonate-induced leaf chlorosis is frequently observed in kiwifruit orchards. A time-course experiment was conducted to investigate the effects of bicarbonate stress on the growth, root acidification, and organic acid and nutrient concentrations of kiwifruit plants treated for 7, 14, 21, 28, and 42 days in hydroponics. After 21 days of bicarbonate treatment, the kiwifruit vines exhibited leaf chlorosis, as indicated by decreased SPAD, chlorophyll a and b as well as carotenoid. Moreover, bicarbonate treatment induced NH₄⁺ accumulation and NO₃⁻ reduction in roots from day 21 onward, thereby increasing the ratio of NH₄⁺ to NO₃⁻ in roots, and the opposite was true for leaves that seemed to respond to bicarbonate earlier than roots but in an inconsistent manner. Before leaf chlorosis, bicarbonate imposition induced succinic acid accumulation and K reduction in roots from day 14 onward. However, the K concentration increased in bicarbonate-treated leaves from day 28 onward. Bicarbonate treatment also reduced P in all plant parts and Fe in leaves from day 21 onward, lowered Zn and enhanced Ca and Mg in roots from day 28 onward. In addition, bicarbonate treatment increased citric acid and ferric chelate reductase (FCR) activity in roots at days 7 and 14, but decreased citric acid and H⁺ extrusion at day 28 and decreased FCR activity at day 42, respectively, indicating that root acidification is duration dependent. These results suggest that, except for succinic acid accumulation, ionic imbalance in the whole kiwifruit plants (particularly N form’s shift) might be an alternative strategy to adapt to bicarbonate stress.

Induced callus from seedlings of Peganum harmala L. and studying harmine compound concentration in vitro and in vivo by GC analysis

Plant tissue culture considers a benefit biotechnological technique for scientific research especially the production of undifferentiation callus cells and regeneration through suspension or static media. The seedlings of Peganum harmala was used as a source to produce callus mass in vitro in static media through different tissue culture media supplemented by varying combinations of plant growth regulators (PGR). The result illustrates that 2 mg/l of Kinitine with 0.5 mg/l of 2, 4-D was efficient to stimulate callus induction with percent 100% in stem and root of P. harmala and this combination gave a high fresh weight, 1954 mg in root and 1170mg in stem and high dry weight in root and stem was 74.60, 60.30 respectively. In a comparative analysis through gas chromatography (GC) the stem and root in field recorded harmine concentration 56.13 and 40.95 μg respectively, which was higher than the in vitro callus induction from stem and root, which may be due to the fact that field plants have not been exposed to plant hormones with concentrations higher than the normal level, which reduced the stimulation of cells producing active compounds.

Magnesium supports nitrogen uptake through regulating NRT2.1/2.2 in soybean

Nitrogen (N) and magnesium (Mg) are two of the essential elements for plant growth. Application of Mg may increase N use efficiency in plants, but the mechanisms underlying Mg and N interaction are not well understood. The objectives of this study were to assess how Mg supply affects N uptake in soybean, and to further investigate underlying molecular mechanisms. Soybean (Glycine max L.) seedlings were provided with various concentrations of Mg under different N conditions in hydroponic cultures. Biomass, nutrient and sugar concentrations, and gene expression were determined. Tissue specificity of gene expression was performed in hairy-root transformants. Increasing Mg supply enhanced N concentration and total N uptake in soybean. The promotive effect is due to the enhanced uptake of nitrate but not ammonium. Moreover, elevating nitrate supply can partially restore growth retardation and leaf chlorosis caused by low Mg availability. A comparative transcriptomic study revealed that two Nitrate Transporter 2 (NRT2) family genes NRT2.1 and NRT2.2 were positively regulated by Mg in roots. Both NRT2.1 and 2.2 are mainly expressed in the exodermis and epidermis of soybean roots, suggesting roles in nitrate uptake. In addition, under low-Mg conditions, expression of NRT2.1 and 2.2 and subsequent N uptake were restored upon exogenous addition of sucrose, implying the possibility that Mg may regulate NRT2.1/2.2 expression through facilitation of sucrose allocation. The results of this study indicate that Mg promotes N uptake through positive regulation of NRT2.1/2.2 expression in soybean roots. This Mg-induced gene expression appears to act through-facilitation of sucrose allocation from shoots to roots.

Mineral elements uptake and physiological response of Amaranthus mangostanus (L.) as affected by biochar

Amaranthus mangostanus L. (amaranth) was hydroponically grown in different concentrations of biochar amended nutrient solution to investigate the mineral elements migration and physiological response of amaranth as affected by biochar. Our results showed that exposure to 26.6 g/L of biochar greatly increased the root and shoot K, Na and Al content, while 2.6 g/L of biochar greatly increased the root Ca and Mg content. The uptake of K and Al notably altered other elements' accumulation in shoots and roots upon the biochar exposure. The ratio of Ca: K in shoots and Mg: K in roots were negatively correlated to the biochar concentrations, while the ratio of Al: Ca and Al: Mg in roots were positively related to the biochar concentrations. The Al: Fe ratio was also polynomial correlated to the concentrations of biochar. The addition of biochar beyond 2.6 g/L resulted in the cell membrane and DNA damages in roots. The activity of SOD and CAT in 6.7 g/L biochar treated roots was significantly elevated as compared to the ones in other biochar treatments and was almost 2-fold of the control. The photosynthetic Fv/Fm intensity and subcellular structure in leaves were also compromised upon exposure to 26.6 g/L biochar. Taken together, biochar could significantly alter the mineral migration in amaranth and physiologically damage in the plants. It is essential to study the effect of biochar within appropriate concentrations on plants prior to wide application in agriculture.

Effects of the exposure of TiO2 nanoparticles on basil (Ocimum basilicum) for two generations

There is a lack of information about the transgenerational effects of titanium dioxide nanoparticles (nano-TiO2) in plants. This study aimed to evaluate the impacts of successive exposure of nano-TiO2 with different surface properties to basil (Ocimum basilicum). Seeds from plants exposed or re-exposed to pristine, hydrophobic, or hydrophilic nano-TiO2 were cultivated for 65 days in soil unamended or amended with 750 mg·kg−1 of the respective particles. Plant growth, concentration of titanium and essential elements, as well as content of carbohydrates and chlorophyll were evaluated. There were no differences on Ti concentration in roots of plants sequentially exposed to pristine or hydrophobic nano-TiO2, or in roots of plants exposed to the corresponding particle, only in the second cycle. However, sequential exposure to hydrophilic particles resulted in 65.2% less Ti in roots, compared to roots of plants exposed the same particles, only in the second cycle. The Ti concentrations in shoots were similar in all treatments. On the other hand, pristine and hydrophilic particles reduced Mg in root by 115% and 81%, respectively, while pristine and hydrophobic particles reduced Ni in shoot by 84% and 75%, respectively, compared to unexposed plants in both cycles. Sequential exposure to pristine nano-TiO2 increased stomatal conductance (214%, p ≤ 0.10), compared to plants that were never exposed. Hydrophobic and hydrophilic nano-TiO2 reduced chlorophyll b (52%) and total chlorophyll (30%) but increased total sugar (186%) and reducing sugar (145%), compared to unexposed plants in both cycles. Sequential exposure to hydrophobic or hydrophilic nano-TiO2 resulted in more adverse effects on photosynthesis but in positive effects on plant growth, compared to pristine nano-TiO2.

Macronutrients Uptake in Soybean as Affected by <i>Bradyrhizobium japonicum</i> Inoculation and Phosphorus (P) Supplements

Field and glasshouse experiments were conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on macronutrient uptake by soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kg P·ha-1. Both treatments were replicated four times in a split plot design. The macronutrients considered were N, P, K, Ca and Mg. Results showed that inoculation with B. japonicum significantly contribute to the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole soybean plant. Likewise, phosphorus supplementation significantly enhanced the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole plant. The use of effective strains of rhizobia and P supplementation was an effective way of enhancing the growth of soybean, eventually the uptake of macronutrients in plant organs.

Tolerance to iron accumulation and its effects on mineral composition and growth of two grass species

This study aimed to assess the influence of excess iron on the capacity of accumulation of this heavy metal, mineral composition, and growth of Setaria parviflora and Paspalum urvillei. Seedlings were submitted to 0.009; 1; 2; 4; and 7 mM of Fe-EDTA. In both species there was an increase in the concentration of Fe, Zn, P, and Ca and a decrease in Mn, K, and Mg in the iron plaque. Both species accumulated more iron in roots. In the shoots, S. parviflora showed higher iron content, except at 7 mM. Iron altered the contents of Fe, Cu, K, and Mg in roots, and of Fe, Mn, Zn, N, P, K, Ca, and Mg in shoots. The two species tolerated high iron concentrations and accumulated high content of this element in both shoots and roots. The iron did not reduce their growth. Both species are indicated for studies aiming restoration of iron-contaminated areas.

Effect of Lime and Farmyard Manure on the Concentration of Cadmium in Water Spinach (Ipomoea aquatica)

An experiment was conducted to investigate the effect of lime and farmyard manure on the concentration of cadmium in water spinach. Water spinach (Ipomoea aquaticacv. Kankon) was grown in sandy loam soil spiked with 5 mg Cd with lime (L) and farmyard manure (M) amendments. The treatments consisted of control, four levels of L (5, 10, 15, and 20 t ), M (5, 10, 15, and 20 t ), and their combinations (55, 1010, 1515, and 2020 t ). Growth parameters of water spinach increased significantly with the addition of lime and farmyard manure in the soil. Lime addition to soil decreased Cd concentration in both shoot and root of water spinach. In control (00), Cd concentration was 62.67 mg in shoot, and 135.5 mg in root. Cadmium concentration decreased by 72, 15, and 66% over the control in shoot and 82, 28, and 76% in the roots correspondingly with the highest rate of lime (20 t ), manure (20 t ), and lime plus manure combinations (20 t 20 t ). The results imply that 5 to 10 t lime could be used in Cd-contaminated soils to reduce Cd uptake by agricultural crops.

Use of Plasma-Based Spectroscopy and Infrared Microspectroscopy Techniques to Determine the Uptake and Effects of Chromium(III) and Chromium(VI) on Parkinsonia Aculeata

Chromium uptake and tolerance by Mexican Palo Verde (Parkinsonia aculeata) (MPV) was studied in a six-month experiment with Cr(III) and Cr(VI) at 60 and 10 mg kg−1, respectively. Chromium and nutrient uptake were determined by ICP-OES and changes in macromolecules were studied by infrared microspectroscopy (IMS). In the Cr(VI)-treated plants, chromium concentration increased in the roots only through the third month, while translocation to stems increased constantly throughout the six months. Cr(III) applications decreased the amount of Zn in leaves and stems (p ≤ 0.05). Cr(VI) increased P and S in all plant tissues and increased Ca in roots, but decreased Ca in stems and leaves, and Mg in roots and stems. Cr(III) decreased P in stems and leaves, while both Cr ions decreased K in all MPV tissues. Relative to untreated plant tissue, the IMS revealed significant changes at 1730 cm−1 and 845 cm−1. Changes at 1730 cm−1 indicated that the cortex and xylem of Cr-treated plants were more proteinaceous. Changes at 845 cm−1 revealed higher lignifications in cortex. However, at the stem level, Cr(VI) decreased lignin deposition in xylem. The data showed that MPV could be useful in the phytoremediation of Cr in moderately impacted soils.

Rate of Nitrogen Application During the Growing Season and Spraying Plants with Urea in the Autumn Alters Uptake of Other Nutrients by Deciduous and Evergreen Container-grown Rhododendron Cultivars

The influence of fall sprays with urea on the uptake of nutrients other than nitrogen (N) was assessed using 1-year-old container-grown Rhododendron L. (Rhododendron ‘H-1 P.J.M’) and azalea (Rhododendron ‘Cannon's Double’) grown with different rates of N. Plants were grown with a complete fertilizer containing different N rates from May to Sept. 2004 sprayed or not with urea in the fall of 2004 and grown with a complete fertilizer containing different N rates in the spring of 2005. Urea sprays altered uptake of nutrients other than just N although fertilizer application with other nutrients ceased before plants were sprayed with urea. Across a wide range of plant sizes and N status, urea sprays increased net phosphorus (P), copper (Cu), and manganese (Mn) uptake and decreased net potassium (K) and magnesium (Mg) uptake during the year of urea application. Spraying plants with urea altered nutrient demand and storage in different plant structures during the winter. For azalea, urea sprays increased P demand by roots, Mn demand by 2004 stems, and Cu demand by stems. Urea also decreased storage of K in roots and 2004 stems of azalea and Mg in roots. For rhododendron, urea sprays increased P demand by 2003 stems and 2004 leaves and Mn demand by 2004 leaves. Urea sprays also decreased storage of K and Mg in 2004 leaves of rhododendron. For both cultivars, urea sprays increased mobilization of iron (Fe) from storage and demand for Fe in stems. Spraying Rhododendron with urea in the fall altered uptake and demand for certain nutrients during the following spring. Urea sprays in the fall of 2004 increased uptake and possibly demand for P, K, and sulfur during the spring of 2005 for both cultivars, the uptake of calcium by rhododendron, and the uptake of Mg and Mn by azalea. Our results indicate that when growers spray plants with urea in the fall, spring fertilizer practices may need to be modified to account for increased uptake or demand of certain nutrients.

Severe Acute Poisoning with Homemade Aconitum napellus Capsules: Toxicokinetic and Clinical Data

Aconitum napellus is an extremely dangerous plant that contains various toxic diterpenoid alkaloids, mainly aconitine, primarily concentrated in the roots. We report a case of acute intoxication of a 21-year-old man admitted to our Emergency Department after the ingestion, in order to sleep, of three homemade Aconitum napellus capsules. Capsules were measured to contain 237 mg of root and 19 µg of aconitine. The patient experienced the first symptoms on wakening 5 hours later with generalized paresthesia, nausea, diarrhea, vertigo, thoracic pain, dyspnea, and dyschromatopsia. At admission, 7 hours after intake, electrocardiographic analysis showed a sinusal bradycardia with polymorphic and bigeminal ventricular extrasystolia. Cardiovascular and neurological symptoms disappeared, respectively, within 11 and 13 hours of ingestion. The patient was discharged from the ICU on day 2. Plasmatic concentrations at H7, H9, H14, H19, and after ingestion were, respectively, of 1.75, 0.75, 0.35, and 0.02 ng/mL. The calculated half-life of aconitine was 3 hours. To our knowledge, this is the first reported case with an aconitine toxicokinetic-effect relationship. The authors stress that clinicians must be aware of possible occurrence of acute poisoning with Aconitum napellus in European countries and in the United States as herbal medicine is becoming increasingly popular.

558 Nutrient Allocation Patterns of Lupinus havardii Wats under Different Preharvest Ca Fertilization Regimes

Lupinus havardii (Big Bend bluebonnet) is a winter annual plant indigenous to the semiarid southwestern U.S. with potential to become a new cut flower commodity. Nothing is presently known about the mineral nutrition of bluebonnet in greenhouse conditions, either in the whole plant or its short-lived cut racemes, and its possible relationship with vase life longevity. At first appearance of floral buds, supplemental Ca treatments (0, 2.5, 5.0, and 10.0 mm Ca using CaCl2) were added to the nutrient solution over a 2-month growing period, to evaluate the influence of Ca on plant nutrient allocation patterns, nutrient uptake and utilization, and raceme physiology after cutting. Ca supplementation increased net Ca uptake per plant by 40%, 77%, and 95% over the control (2.5, 5.0, and 10.0 mm Ca, respectively; P < 0.05). The increased Ca uptake per plant increased Ca concentration in racemes (a weak Ca sink), which resulted in marginal increases in vase life duration (1 day). This positive influence on vase life duration was not significant due to limited number of raceme replicates. When plants were supplemented with 5 mm Ca, the net accumulation of Ca, P, K, and Mg in roots increased by 4 to 5 times over the control roots. These increases occurred in parallel to an increase in root dry matter production. Similar patterns were observed in the net accumulation of Ca, P, K, and Mg per plant. In our conditions, Ca supplementation (5 mm) enriched raceme Ca concentration as well as whole-plant consumption of Ca, P, K, and Mg in bluebonnet plants. These data will be useful in developing fertilization strategies for this new and promising greenhouse floral crop.

Aluminium accumulation in root cell walls coincides with inhibition of root growth but not with inhibition of magnesium uptake in Norway spruce

High levels of aluminium in the soil solution of forest soils cause stress to forest trees. Within the soil profile, pH and aluminium concentration in the soil solution vary considerably with soil depth. pH strongly influences the speciation of A1 in solution, and is a factor when considering toxicity of A1 to roots. Norway spruce (Picea abies[L.] Karst.) seedlings were grown for 7 weeks in nutrient solutions at pH 3.2, 4.0 or 5.0 containing 0, 100 or 400 µM A1. At the end of this period, seedling growth, the cation exchange capacity of the roots and the amount of exchangeable Ca and Mg in roots were determined. A1 concentrations in whole roots, root segments, and in needles were measured. Using X‐ray microanalysis, the concentrations of Al, Ca, Mg and P were determined in cortical cell walls. We wanted to test the hypotheses that (1) the amount of Al bound to cation exchange sites can be used as a marker for Al toxicity and (2) the Mg concentration of needles is controlled by the amount of Mg bound to cation exchange sites. Low pH reduced the inhibition of Al on root growth and shoot length. Both low pH and Al lowered the concentration of Ca and Mg in needles. Al concentrations in the roots decreased as the pH decreased. In the roots, Al displaced Mg and Ca from binding sites at the root cortical cell walls. A comparison of the effects of Al at the different pH values on root growth and Mg concentration in the needles, suggests that, at pH 5.0, an Al fraction in the apoplast inhibits root growth, but does not affect Mg uptake. This fraction of Al is not available for transport to the shoots. In contrast, Mg uptake is strongly affected by Al at pH 3.2, although only very low levels of Al were detected in the roots. Thus, Al accumulation in the apoplast is a positive marker for Al effects on root growth, but not Mg uptake. The Mg concentration of needles is not controlled by the amount of Mg bound to cation exchange sites.