INTERACTION OF MOLYBDENUM AND PHOSPHORUS SUPPLY ON UPTAKE AND TRANSLOCATION OF PHOSPHORUS AND MOLYBDENUM BY BRASSICA NAPUS

A hydroponic trial was conducted to assess interaction of molybdenum (Mo) and phosphorus (P) on uptake and translocation of P and Mo by Brassica napus. Molybdenum was applied at four rates (0, 0.01, 0.1 and 1 mg L^?1) and P at three rates (1, 30, and 90 mg L^?1) in nutrient solution. The results indicated that P increased shoot growth and 0.01 mg L^?1 Mo improved the growth of shoots and roots. Molybdenum increased shoot P uptake and root P concentration and uptake when higher P was provided, and had a stimulating effect on P translocation from shoots to roots. P increased shoot Mo concentration and uptake, decreased those in roots, and enhanced Mo transport from roots to shoots. These results implied that both Mo and P had beneficial effects on Mo and P absorption and translocation and co-application of them were necessary to promote growth and utilization of Mo and P for Brassica napus.     

Co-application of molybdenum and selenium fertilizers increase uptake,recovery and harvest index of molybdenum and selenium in pepper crop

A pot trial was conducted to clarify the interactions of molybdenum (Mo) and selenium (Se) fertilizers on uptake, harvest index and recovery of Mo and Se by pepper crop (Capsicum frutescens L.). Mo was applied at three rates (0, 0.15 and 0.3 mg kg^?1) and Se at three rates (0, 0.4 and 0.8 mg kg^?1) in soil. Appropriate application of Mo increased Se concentrations in pepper fruit, stem, leaf and root especially in the presence of Se fertilizer. Appropriate application of Se increased Mo concentrations in pepper fruit, stem, leaf and root particularly in the presence of Mo fertilizer. Both Mo and Se had beneficial effects on harvest index and recovery of Mo and Se. These results indicated that there is significant synergetic effect on Mo and Se absorption and translocation, and co-application of these two elements is necessary to produce Mo and Se-rich pepper.     

ALLEVIATION OF CADMIUM-TOXICITY BY APPLICATION OF ZINC AND ASCORBIC ACID IN BARLEY

ABSTRACT

Effect of cadmium (Cd) on biomass accumulation and physiological activity and alleviation of Cd-toxicity by application of zinc (Zn) and ascorbic acid in barley was studied, using semisolid medium culture including 15 treatments [four Cd concentration treatments: 0.1, 1, 5, 50?µmol?L^?1, four treatments with addition of 300?µmol?L^?1 Zn or 250?mg?L^?1 ascorbic acid (ASA) based on these four Cd concentrations, respectively, and three controls: basic nutrient medium, and with Zn or ASA, respectively]. Cadmium addition to semisolid medium, at a concentration of 1, 5, and 50?µmol?L^?1, inhibited biomass accumulation and increased malondialdehyde (MDA) content of barley plants, while the addition of 0.1?µmol?L^?1 Cd increased slightly dry mass. There was a tendency to a decrease in Zn, copper (Cu) concentrations both in shoots and roots and iron (Fe) in shoots of barley plants exposed to 1 to 50?µmol?L^?1 Cd. In addition, there were indications of a stress repose characterized by increased superoxide dismutase (SOD) and peroxidase (POD) activities relative to plants not subjected to Cd. The physiological changes caused by Cd toxicity could be alleviated to different extent by application of 300?µmol?L^?1 Zn or 250?mg?L^?1 ASA in Cd stressed plants. The most pronounced effects of adding Zn or ASA in Cd stressed medium were expressed in the decreased MDA and increased biomass accumulation, e.g., MDA contents were reduced (p≤0.01) by 4.8%–17.8% in shoots and 0.5%–19.7% in roots by adding 300?µmol?L^?1 Zn, in 50?µmol?L^?1 Cd stressed plants, and by 1.3%–7.4% in shoots and 2.6%–4.5% in roots by application of 250?µmol?L^?1 ASA, respectively. However, ASA addition may enhance Cd translation from root to shoot, accordingly, ASA would be unsuitable for the edible crops grown in Cd contaminated soils to alleviate phytotoxicity of Cd.     

Interactive Effects of Lanthanum and Cadmium on Plant Growth and Mineral Element Uptake in Crisped-Leaf Mustard Under Hydroponic Conditions

Plant growth and mineral element accumulation in Brassica juncea var. crispifolia (crisped-leaf mustard) under exposure to lanthanum (La) and cadmium (Cd) were studied by employing a hydroponic experiment with a complete two-factorial design. Four levels of La (0.05–5.0 mg L^?1) and two levels of Cd (1.0 and 10.0 mg L^?1) were used in this experiment. Lanthanum did not improve plant growth in this experiment. Addition of La (≥ 1.0 mg L^?1) or Cd (≥ 10 mg L^?1) to the solution inhibited root elongation. Lanthanum treatments reduced accumulations of iron (Fe), manganese (Mn), and zinc (Zn) in roots, and Mn in shoots. Lanthanum at ≥ 1.0 mg L^?1 limited the Cd translocation from roots to shoots and thus decreased the accumulation of Cd in shoots. Cadmium had no influence on La accumulations in roots, but inhibited the accumulation of La in shoots. The study results suggest that applications of rare earth elements in vegetables would be potentially risky to human health.     

EFFECT OF LANTHANUM ON RICE PRODUCTION,NUTRIENT UPTAKE,AND DISTRIBUTION

ABSTRACT

Split root solution culture experiments were conducted to study the effects of the rare earth element lanthanum (La) on rice (Oryza sativa) growth, nutrient uptake and distribution. Results showed that low concentrations of La could promote rice growth including yield (0.05 mg L^?1 to 1.5 mg L^?1), dry root weight (0.05 mg L^?1 to 0.75 mg L^?1) and grain numbers (0.05 mg L^?1 to 6 mg L^?1). High concentrations depressed grain formation (9 mg L^?1 to 30 mg L^?1) and root elongation (1.5 mg L^?1 to 30 mg L^?1). No significant influence on straw dry weight was found over the whole concentration range except for the 0.05 mg L^?1 treatment. In the pot and field experiments, the addition of La had no significant influence on rice growth.Lanthanum had variable influence on nutrient uptake in different parts of rice. Low concentrations (0.05 mg L^?1 to 0.75 mg L^?1) increased the root copper (Cu), iron (Fe), and magnesium (Mg), and grain Cu, calcium (Ca), phosphorus (P), manganese (Mn), and Mg uptake. High concentrations (9 to 30 mg L^?1) decreased the grain Ca, zinc (Zn), P, Mn, Fe and Mg, and straw Ca, Mn, and Mg uptake. With increasing La concentration, root Zn, P, Mn, Cu, and Ca concentrations increased, and grain Ca and Fe, and straw Mn, Mg, and Ca concentrations decreased. Possible reasons are discussed for the differences between the effects of La in nutrient solutions and in pot and field experiments.     

Selenium in lemon balm plants: Productivity,phytotoxicity and drought alleviation

Since studies on the effects of selenium (Se) supplementation in water-stressed plants have mainly focused on cereal crops, the specific reports regarding Se-mediated adaptation to drought stress in medicinal vegetables are scant. Thus, we investigated the responses of Melissa officinalis to Se supplementation. Selenium contents were increased in leaves and grains by supplemental Se. Selenium foliar application at 1 mg l^?1 could be useful to increase the vegetative and reproductive growth of Se-enriched plants under well-watered conditions but at 20 mg l^?1 led to toxicity and caused damage to shoots. Drought stress significantly inhibited plant growth by chlorophyll degradation and reduced net carbon dioxide (CO₂) assimilation rate. Although Se at 1 mg l^?1 could increase biomass production under well-watered conditions in addition to the stimulation of antioxidant system under water stress, it could not ameliorate the negative effect of drought on productivity.     

Root zone selenium reduces cadmium toxicity by modulating tissue-specific growth and metabolism in maize (Zea mays L.)

The effects of selenium (Se) cadmium (Cd) interactions on plant growth and metabolism are not fully clear. In the present study, we assessed whether Se could alleviate the toxic effects of Cd on growth and metabolism of maize. Seeds of maize variety FH-985 were sown in pots filled with sand treated with CdCl₂ (0, 50 and 100 µM) and Se (0, 2 and 4 mg L^?1) through Hoagland’s nutrient solution. Low Se (2 mg L^?1) increased germination percentage and rate, while high Se (4 mg L^?1) increased fresh and dry biomass under Cd stress. Interestingly, all Se concentrations were effective in alleviating the toxic effects of Cd on photosynthetic pigments, whereas higher Se mitigated the Cd-induced oxidative stress and increased flavonoids both in the shoots and roots while phenolics in the roots. The results demonstrated that root zone Se altered tissue-specific primary metabolism in maize. Furthermore, low Se mitigated the Cd-induced decrease in total proteins in the root. Overall, Se-mediated decrease in the oxidative stress in the shoots while increase of secondary metabolites in the roots helped the plants to grow faster at early growth stage and caused increase in the biomass under different Cd regimes.     

The Physiology and Biochemical Tolerance of Cabbage to Se (VI) Addition to the Soil and by Foliar Spraying

The effects of selenium (Se) (VI) soil fertilization with 2 μg Se L^?1 or foliar spraying twice with 20 mg Se L^?1 in the form of sodium (Na) selenate on the physiological and biochemical characteristics of cabbage plants were studied. The ability of the plants to take up Se and translocate it to different parts of the plants was also studied. Despite the high concentration of Se in the foliar solution, there was no effect on photosynthesis, transpiration rate, photochemical efficiency of PSII, or electron transport system activity. The amount of chlorophyll and anthocyanins were unchanged. At harvest, the concentration of Se in control plants was lower than 100 ng Se g^?1 dry weight (DW), while plants treated with 20 mg Se L^?1 contained 5500 ng Se g^?1. Selenium enriched cabbage could be used in human nutrition. The tolerance of cabbage to Se could be explained by the formation of insoluble compounds that are not available for the plant.     

Effect of potassium on uptake and translocation of sodium and potassium in Chinese cabbage under NaCl stress

To investigate the influence of potassium (K⁺) on the salinity tolerance of Chinese cabbage (Brassica pekinensis Rupr.) seedlings, the plants were cultured at three K⁺ levels (0, 5, or 10?mM), under normal (0?mM NaCl) and high-salt (100?mM NaCl) conditions. The results indicated that the dry weight of Chinese cabbage increased with the application of K⁺ under salt stress. Addition of K⁺ increased K⁺ concentrations and suppressed sodium (Na⁺) concentration, which eventually increased the K⁺/Na⁺ ratios in roots or shoots. Application of K⁺ enhanced the uptake of K⁺ and suppressed the uptake of Na⁺. Moreover, the ratios of shoot-K⁺/root-K⁺ increased considerably, but the ratios of shoot-Na⁺/root-Na⁺ decreased in response to K⁺ application. It was concluded that the application of K⁺ could enhance the salt stress tolerance in Chinese cabbage because more K⁺ than Na⁺ was absorbed and translocated from roots to shoots.     

Selenium uptake response among selected wheat (Triticum aestivum) varieties and relationship with soil selenium fractions

Some South Dakota soils contain high levels of available selenium (Se) for crop uptake. A field study was conducted to determine if any popular wheat (Triticum aestivum) varieties demonstrate differential Se uptake. A total of 280 samples including eight winter wheat and ten spring wheat varieties were analyzed for grain Se concentration and uptake for two growing years. Soil samples were sequentially fractionated into (1) plant available (0.1?M KH₂PO₄ extractable) and (2) conditionally available (4?M HCl extractable) pools and analyzed separately for total Se. Selenium concentration in wheat grain had a wide variability and the mean value over two years was 0.63?µg?Se?g^?1. Grain Se concentration and Se uptake were not significantly different by wheat varieties tested in this study. Grain Se concentration was significantly correlated with soil Se levels, soil pH, and orthophosphate-P content within a location, but grain Se concentration was strongly influenced by geographical location in which different amounts of soil Se bioavailability occurred.     

Effects of foliar selenium application on some physiological and phytochemical parameters of Vitis vinifera L. cv. Sultana under salt stress

Abstract

In this research the effect of foliar application of selenium (Se) at four levels (Na₂OSe₄; 0, 5, 10 and 20?mg L^?1) was evaluated on some phytochemical characteristics of Sultana grapevine under different salinity levels (NaCl; 0 or 75?mM). The vines were fed twice a week with Hoagland nutrient solution and Se was foliar applied twice with 24 intervals. During growing period, plant height, leaf number and leaf area were recorded. Moreover, at the end of experiment, mature leaves from middle nods of canes were used for measurement of some phytochemical indices. According to results, Se application had a positive effect on plant height, leaf numbers, leaf area and photosynthetic pigments content especially at 5?mg L^?1 and to some extent 10?mg L^?1 Se levels. Under salinity stress, foliar application of Se at 5?mg L^?1 considerably decreased vines leaves electrolyte leakage and lipid peroxidation values compared to non se-treated plants under salinity stress condition. Selenium had an additive effect on salinity stress (75?mM NaCl) induced accumulation of total phenol, total flavonoid, soluble sugars and proline content in leave of vines. Moreover, the interaction of salinity and Se at 5 and 10?mg L^?1 improved leaves antioxidant enzymes activities in Sultana grapevine. Likewise, foliar application of Se improved leaf mineral content in 75?mM NaCl -treated vines. Totally, foliar application of selenium (Se at 5 or 10?mg L^?1) increased salt tolerance through improvement in nutritional balance and by enzymatic and non-enzymatic antioxidant capacity in grapevine leaves.     

Selenium Behavior in Open Bulk Precipitation, Soil Solution and Groundwater in Alluvial Fan Area in Tsukui, Central Japan

A monitoring study was carried out in an alluvial fan area in Tsukui, Central Japan during the study period of 1999–2003, in order to explain selenium (Se) behaviors in ecosystem combined with air, soil and groundwater. Monthly Se concentrations in open bulk precipitation (rainfall+aerosol, gaseous deposition and etc.), soil solution (collected by porous ceramic-cup) and groundwater ranged from 0.1 to 1.4 μg L^?1 (volume-weighted average: 0.34 μg L^?1), 0.21 to 1.0 μg L^?1 (0.48 μg L^?1) and 1.6 to 2.4 μg L^?1 (2.2 μg L^?1), respectively. Se concentration in open bulk precipitation was negatively correlated with the rainfall amount. Se concentration in soil solution significantly increased with DOC concentration in soil solution. Besides, despite atmospheric Se input and rainfall to the grassland study area, Se concentration in soil solution and groundwater received no significant effect from the rainfall amount, pH, Se, DOC, SO₄ ^2?, NO₃ ^? and EC in rainfall. Even though Se concentrations in groundwater were significantly correlated with soil solution volume, Se, DOC and NO₃ ^? and groundwater level, the result of multiple regression analyses (MRA) indicated that the groundwater Se was negatively influenced by groundwater level, which depended on groundwater recharge. Se was transported into the groundwater through the groundwater recharge that largely increased in this alluvial fan study area after heavy rain.     

The influence of phosphate fertilizer application levels and cultivars on cadmium uptake by Komatsuna (Brassica rapa L. var. perviridis)

Cadmium (Cd) is a common impurity in phosphate fertilizers and application of phosphate fertilizer may contribute to soil Cd accumulation. Changes in Cd burdens to agricultural soils and the potential for plant Cd accumulation resulting from fertilizer input were investigated in this study. A field experiment was conducted on Haplaquept to investigate the influence of calcium superphosphate on extractable and total soil Cd and on growth and Cd uptake of different Komatsuna (Brassica rapa L. var. perviridis) cultivars. Four cultivars of Komatsuna were grown on the soil and harvested after 60 days. The superphosphate application increased total soil Cd from 2.51 to 2.75?mg?kg^?1, 0.1?mol?L^?1 hydrochloric acid (HCl) extractable Cd from 1.48 to 1.55?mg?kg^?1, 0.01?mol?L^?1 HCl extractable Cd from 0.043 to 0.046?mg?kg^?1 and water extractable Cd from 0.0057 to 0.0077?mg?kg^?1. Cd input reached 5.68?g?ha^–1 at a rate of 240?kg?ha^–1 superphosphate fertilizer application. Superphosphate affected dry-matter yield of leaves to different degrees in each cultivar. ‘Nakamachi’ produced the highest yield in 2008 and ‘Hamami No. 2’ in 2009. Compared with the control (no phosphate fertilizer), application of superphosphate at a rate of 240?kg?ha^–1 increased the Cd concentration in dry leaves by 0.14?mg?kg^?1 in ‘Maruha’, 1.03?mg?kg^?1 in ‘Nakamachi’, 0.63?mg?kg^?1 in ‘SC8-007’ in 2008, and by 0.19?mg?kg^?1 in Maruha’, 0.17?mg?kg^?1 in ‘Hamami No. 2’, while it decreased by 0.27?mg?kg^?1 in ‘Nakamachi’ in 2009. Field experiments in two years demonstrated that applications of different levels of calcium superphosphate did not influence Cd concentration in soil and Komatsuna significantly. However, there was a significant difference in Cd concentration of fresh and dry Komatsuna leaves among four cultivars in 2008 and 2009. The highest Cd concentration was found in the ‘Nakamachi’ cultivar (2.14?mg?kg^?1 in 2008 and 1.91?mg?kg^?1 in 2009). The lowest Cd concentration was observed in the ‘Maruha’ cultivar (1.51?mg?kg^?1?dry weight (DW)) in 2008 and in the ‘Hamami No. 2’ cultivar (1.56?mg?kg^?1?DW) in 2009. A decreasing trend in Cd concentration was found in ‘Nakamachi’, followed by ‘SC8-007’, ‘Hamami No. 2’ and ‘Maruha’ successively. It is necessary to consider a low-uptake cultivar for growing in a Cd polluted soil. In these two years’ results, ‘Maruha’ cultivar was the lowest Cd uptake cultivar compared to the others.     

Nitrogen and phosphorus leaching under the potential biennial oilseed plant Lepidium campestre L. in a field trial

Domestication of biennial Lepidium campestre L. offers possibilities for more varied crop rotations in cold regions, with increased crop cover during winter. In the first winter after sowing, L. campestre can reduce nitrogen (N) leaching before harvesting in the second year. In this system no soil tillage is needed during the first year, unlike in systems with annual crops. A three-year leaching study on loam soil in southern Sweden revealed significantly (p?<?0.05) lower flow-weighted mean total nitrogen (TN) concentration in drainage water under L. campestre (5.8 mg TN L^?1) compared with a control treatment (no catch crop and autumn mouldboard ploughing) (9.6 mg TN L^?1). In two years of observations, Lepidium campestre had lower flow-weighted mean TN concentration (6.2 mg L^?1) than a mixed Vicia villosa L. (hairy vetch)/Secale cereale (winter rye) catch crop (10.2 mg L^?1) and rather similar concentration to a Raphanus sativus (oilseed radish) catch crop (5.7 mg TN L^?1), both sown after harvest of the main crop. However, L. campestre appeared to have a negative effect on total phosphorus (TP) leaching, with TP concentration in drainage of 0.05 mg L^?1 compared with 0.01–0.02 mg L^?1 for the other catch crops and the control.     

Establishment of seed germination and micropropagation protocols for Senegalia nigrescens,a potential anti-virulent species

This study describes seed germination and micropropagation of Senegalia nigrescens, an economic, medicinal and nitrogen-fixing species of South Africa. Seeds of S. nigrescens were subjected to pre-sowing treatments including soaking in cold water for 24?h, sulphuric acid (H₂SO₄) or hydrochloric acid (HCl) for 4, 8 and 12?min and mechanically scarifying seeds before sowing on Petri plates with wet filter paper. Mechanically-scarified seeds were also sown aseptically on a filter paper bridge, plain agar, ½ or full strength Murashige and Skoog (MS) basal medium. Single nodal explants from MS-derived seedlings were grown on MS media supplemented with 0.0, 0.5, 1.0 and 2.0 mg?L^?1 of benzylaminopurine (BAP) or kinetin (KIN) and a combination of 0.5 mg?L^?1 of BAP and KIN to investigate shoot multiplication. No significant differences were observed in the number of shoots produced across all treatments. However, the treatment containing 1.0 mg?L^?1 KIN produced a significantly higher shoot length (14.17?±?5.20 mm) than 0.5, 1.0 and 2.0 mg?L^?1 BAP (7.67?±?3.87, 6.75?±?2.93 and 8.70?±?3.56 mm, respectively). The highest rooting rate (16.7%) was obtained on ¼ strength MS supplemented with either indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) at concentrations 1.0 and 0.5 mg?L^?1, respectively. Rooted plantlets were successfully acclimatised with a 66.7% survival rate. The findings from this study would be of great benefit for the commercial propagation of S. nigrescens.     

Micronutrient availability in soils of Northwest Bosnia and Herzegovina in relation to silage maize production

Maize (Zea mays L.) is the most widely grown crop in Bosnia and Herzegovina especially in Northwest part of the country. Considering that, the maize is extremely sensitive to micronutrient deficiency the main aim of this study was to asses: (1) micronutrient availability in soil, (2) micronutrient status in silage maize; and (3) the relationship between micronutrient soil availability and maize plant concentration. Soil samples for micronutrient availability (n?=?112) were collected from 28 farms in 7 municipalities. Plant available micro- and macro- nutrients in soil were extracted using Mehlich-3, except plant available Se was extracted using 0.1M KH₂PO₄. Result showed that on average there was no significant difference between different soil types regarding their potential in plant available nutrients. P deficiency was present both, in soil and plants in whole region. Soil extractable P was ranging from 0.003–0.13?g?kg^?1 and total plant P was ranging from 0.79–4.95?g?kg^?1. Zinc deficiency was observed in two locations both in soil (0.71?mg?kg^?1; 0.79?mg?kg^?1) and plant (11.5?mg?kg^?1; 15.8?mg?kg^?1). Potential Se soil deficiency was observed on some locations, while Se plant status is not high enough to meet daily requirements of farm animals. Extractable soil nutrients could be used as relatively good predictor of potential soil and plant deficiencies, but soil nutrient interactions and climate conditions are highly effecting the plant uptake potential.     

MODULATION OF MACRONUTRIENTS UPTAKE AND TRANSLOCATION IN Mn-TREATED RICE IN EARLY STAGES OF VEGETATIVE GROWTH

The effect of increasing manganese (Mn) concentrations on calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P) absorption and translocation was studied in rice (Oryza sativa L. cv. Safari), before and after the end of mobilization of seed reserves. Rice plants were grown over a 15-, 21-, and 28-day period in nutrient solutions containing Mn concentrations varying between 0.125 and 32 mg L^?1. It was found that increasing Mn concentrations in the nutrient solution was coupled to an increasing net uptake, total shoot accumulation, and root and shoot contents of this metal during all the experimental periods. Concerning the translocation rates, in 15-day-old plants a decrease was found after the 2 mg L^?1 Mn treatment, but from the 21st day onward an increase was found until the highest treatment. The modulating action of Mn in macronutrient accumulation displayed different patterns among the experimental periods. In the root tissues of 15-day-old plants, Ca decreased significantly until the 2 mg L^?1 treatment and Na increased. In the shoots, the contents of P and Na decreased, but K and Mg showed significant increases. Until the 32 mg L^?1 Mn treatment, the ratio between root and shoot concentrations of K and Mg decreased in these plants. A similar pattern was also found for Ca until the 2 mg L^?1 Mn treatment. That ratio increased for Na. Plant total amount of Ca sharply decreased. Shoot total amount of Na and P also decreased, but the pattern of Ca increased until the 2 mg L^?1 Mn treatment. The concentrations of K increased in the root tissues 21 days after germination, but the levels of Ca, Mg, Na, and P decreased. In the shoots, the concentrations of Ca and Mg decreased significantly. Until the 32 mg L^?1 Mn treatment, the ratio between root and shoot concentration of Na and P increased, whereas those of Ca and Mg decreased. An increase was found for the plant and shoot total amount of Ca, K, and Mg until the last Mn treatment, but an opposite trend was found for Na and P. Additionally, until the 32 mg L^?1 Mn treatment, an increase was found for the proportions of Ca and Mg translocated to the shoot, but an opposite trend was detected for P. It was concluded that before and after the end of the mobilization of seed reserves, the net uptake rate of Ca is reversed, and, moreover, a similar trend is shown for the net translocation of Mg. A major implication of this process is the alteration of the related pattern for shoot accumulation. Eventually a different selectivity of the K⁺:Na⁺ ratio is also developed in the roots.     

Growth Response and Selenium and Boron Distribution in Broccoli Varieties Irrigated with Poor Quality Water

Abstract

Selenium (Se), and boron (B), and salinity contamination of agricultural drainage water is potentially hazardous for water reuse strategies in central California. This greenhouse study assessed tolerance and Se, B, and chloride (Cl^?) accumulation in different varieties (Emerald City, Samurai, Greenbelt, Marathon) of broccoli (Brassica oleracea L.) irrigated with water of the following different qualities: (1) non‐saline [electrical conductivity (EC) of <1 dS m^?1]; (2) Cl^?/sulfate salinity of ～5 dS m^?1, 250 µg Se L^?1, and 5 mg B L^?1; and (3) non‐saline and 250 µg Se L^?1. One hundred and ten days after transplanting, plants were harvested and dry weight (DW) yields and plant accumulation of Se, B, and Cl^? was evaluated in floret, leaf, and stem. Irrespective of treatments floret yields from var. Samurai were the lowest among all varieties, while floret yields from var. Marathon was the only variety to exhibit some sensitivity to treatments. For all varieties, plant Se concentrations were greatest in the floret (up to 51 mg kg^?1 DW) irrespective of treatment, and B and Cl^? concentrations were greatest in the leaves; 110 mg B kg^?1 DW and 5.4% Cl^?, respectively. At post harvest, treatment 2 (with salinity, B, and Se) increased soil salinity to almost 6 dS m^?1, total Se concentrations to a high of 0.64 mg kg^?1 DW soil, and water soluble B concentrations to a high of 2.3 mg B L^?1; soluble Se concentrations were insignificant. The results indicate that var. Emerald City, Greenbelt, and Marathon should be considered as recipients of moderately saline effluent enriched with Se and B under field conditions.     

Cadmium Uptake by Winter Wheat Seedlings in Response to Interactions Between Phosphorus and Zinc Supply in Soils

ABSTRACT

Effects of application of zinc (Zn) (0, 1, 5, 10 mg kg^?1 soil) and phosphorus (P) (0, 10, 50, 100 mg kg^?1 soil) on growth and cadmium (Cd) accumulations in shoots and roots of winter wheat (Triticum aestivum L.) seedlings were investigated in a pot experiment. All soils were supplied with a constant concentration of Cd (6 mg kg^?1 soil). Phosphorus application resulted in a pronounced increase in shoot and root biomass. Effects of Zn on plant growth were not as marked as those of P. High Zn (10 mg kg^?1) decreased the biomass of both shoots and roots; this result may be ascribed to Zn toxicity. Phosphorus and Zn showed complicated interactions in uptake by plants within the ranges of P and Zn levels used. Cadmium in shoots decreased significantly with increasing Zn (P < 0.001) except at P addition of 10 mg kg^?1. In contrast, root Cd concentrations increased significantly except at Zn addition of 5 mg kg^?1 (P < 0.001). These results indicated that Zn might inhibit Cd translocation from roots to shoots. Cadmium concentrations increased in shoots (P < 0.001) but decreased in roots (P < 0.001) with increasing P supply. The interactions between Zn and P had a significant effect on Cd accumulation in both shoots (p = 0.002) and roots (P < 0.001).     

Enrichment of lithium in lettuce plants through agronomic biofortification

Abstract

Biofortification of crops with lithium (Li) is a new trend in agriculture and researches on this subject still scarce, therefore, this work aims to evaluate the accumulation potential and the effects in agronomic characteristics of lettuce (Lactuca sativa L.) submitted to foliar application of two Li chemical sources and different concentrations. The experiment was conducted in a greenhouse and the applications of lithium hydroxide (LiOH) and lithium sulfate (Li₂SO₄) were done via foliar spray at concentrations ranging from 0 to 40?mg dm^?3. The applications were divided into three applications distributed at 15, 25, and 35?days after transplanting. Positive and promising results were observed in agronomic characteristics and Li in accumulation. High concentrations of Li (40?mg dm^?3) may compromise the development of lettuce plants, however, lower concentrations applied (16 to 26?mg dm^?3 of Li) promoted an increase in dry weight of roots and shoot/root ratio, both chemical forms, and stem diameter and specific leaf area, Li₂SO₄, suggesting beneficial effect of this element. Li accumulation in shoots depend on the concentrations of this element in the applied solution of Li but not on its chemical form.