Calcium Sulfate Improves Salinity Tolerance in Rootstocks of Plum

ABSTRACT

Three vegetative rootstocks of plum (Prunus domestica), Marianna GF 8-1 (Prunus cerasifera × munsoniana), Myrobolan B (P. Cerasifera) and Pixy (P. Insititia) were grown in pots containing sand and irrigated with complete nutrient solution to investigate the effect of calcium sulfate supplied to the nutrient solution on plants grown under salt stress. Treatments were (1) control (C): nutrient solution alone; (2) S (salinity stress): 40 mM NaCl; (3) S+Ca1: 40 mM NaCl +2.5 mM calcium (Ca) and (4) S+Ca₂: 40 mM NaCl + 5 mM Ca. Calcium was supplied as CaSO₄. The plants grown under 40 mol L^?1 NaCl produced less dry matter and had lower chlorophyll content than those without NaCl. Supplementary CaSO₄ at both 2.5 and 5 mM concentrations ameliorated the negative effects of salinity on plant dry matter and chlorophyll content. Salt treatment impaired membrane permeability by increasing electrolyte leakage. The addition of calcium sulfate partially maintained membrane permeability. Sodium (Na) concentration in plant tissues increased in both leaves and roots of plants under the high NaCl treatment. Pixy had much lower Na. The CaSO₄ treatments lowered significantly the concentrations of Na in both leaves and roots. Pixy was more tolerant to salinity than the other two rootstocks. The accumulation of Na in leaves and roots indicates a possible mechanism whereby Pixy copes with salinity in the rooting medium, and/or may indicate the existence of an inhibition mechanism of Na transport to leaves. Concentrations of Ca and K were lower in the plants grown at high NaCl than in those under the control treatment, and these two element concentrations were increased by calcium sulfate treatments in both leaves and roots, but remained lower than control values in most cases.     

Effects of Zinc on Root Morphology and Antioxidant Adaptations of Cadmium-Treated Sedum alfredii H.

ABSTRACT

The study demonstrated S. alfredii is an excellent cadmium (Cd)/zinc (Zn) hyperaccumulator as Cd and Zn concentrations in leaves reached 2,183 and 13,799 mg kg^?1 DW, respectively. There was a significant increase in root morphological parameters induced by 50 and 500 μM Zn supplement; however, a sharp decrease in these parameters occurred when treated with 100 μM Cd +1000 μM Zn. The inhibited root dehydrogenase activity in 100 μM Cd treated plants was restored to control levels when supplemented with 500 μM Zn. Moderate Zn supplement did not produce significant changes in (malondialdehyde) MDA concentrations as compared with those treated with Cd alone. Variations of the antioxidative enzymes proved an ineffective role in coping with metal-stress in S. alfredii. Combined Cd and Zn treatment significantly enhanced ascorbic acid (AsA) and glutathione (GSH) contents in leaves of S. alfredii, as compared with those treated with Cd alone. Thus, Zn may rely on the involvement of GSH in detoxification and tolerance.     

Cadmium effects on influx and transport of mineral nutrients in plant species

Solution culture experiments were conducted under controlled environmental conditions to determine the effects of cadmium(II) [Cd(II)] activity (0, 8, 14, 28, 42, and 54 μM) on influx (IN) into roots and transport (TR) from roots to shoots of zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), calcium (Ca), magnesium (Mg), phosphorus (P), and sulfur (S) in ryegrass (Lolium perenne L.), maize (Zea mays L.), white clover (Trifolium repens L.), and cabbage (Brassica oleracea var. capitata L.). Shoot and root dry matter (DM) decreased with increased external Cd, and plant species differed extensively. Ryegrass and cabbage were relatively tolerant to Cd toxicity compared to white clover and maize. Influx and TR of Cu, Zn, Fe, Mn, Ca, and Mg were lower with increasing external Cd compared to controls, and species also differed. Influx and TR of P were enhanced in each species with up to 14 μM Cd, decreased in white clover and cabbage at higher Cd levels, while in maize and ryegrass continued to increase as Cd increased. Influx and TR of S were high in white clover at 8 μM Cd and decreased as Cd increased. Influx of S was high in ryegrass, but TR of S remained relatively constant as Cd increased. Influx and TR of S did not significantly change in maize, but decreased in cabbage as Cd increased. With Cd up to 14 μM, decreases in both IN and TR of Zn, Fe, Mn, Ca, and Mg were greater in white clover than in cabbage. Sensitivity of the dicotyledonous plant species to Cd toxicity might have been associated with Cd effects on IN and TR of Fe, Mn, Ca, and Mg. However, differences in plant sensitivities to Cd toxicity between ryegrass and maize were not reflected in Cd effects on IN and TR of mineral nutrients.     

Concentrations of Major and Minor Mineral Elements in Different Organs of Kosteletzkya virginica and Saline Soils

Abstract

Kosteletzkya virginica (L.) Presl. is a perennial dicot halophytic species that grows in brackish portions of coastal tidal marshes of the mid-Atlantic and southeastern United States. It was introduced into Northern Jiangsu, China, by the Halophyte Biotechnology Center (University of Delaware, Newark, DE) as a species with potential to improve the soil and develop ecologically sound saline agriculture. Fifteen major and minor elements [calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), lead (Pb), cadmium (Cd), aluminum (Al), copper (Cu), lithium (Li), cobalt (Co), and vanadium (V)] in roots, stems, leaves, and seeds of Kosteletzkya virginica and saline soils were measured in the study. Concentrations of Al, Fe, Zn, Mn, V, and Pb were the highest in soils, whereas concentrations of Na, Li, Cu, Ca, and Mg were the highest in the roots, stems, and leaves, respectively, and concentrations of K and P were the highest in the seeds. Potassium, P, Mg, and Ca were the main constituents in the seeds, and concentrations of Fe, Li, Mn, Zn, and Cu in seeds were relatively high. However, concentrations of Na and Al were very low in the seeds. The K/Na ratio in the seeds was 34.26, and the Ca/P ratio was 0.52, which was less than the maximum tolerable value for the human diet. These proportions were considered to be an advantage from a nutritional point of view. From roots to stems to leaves, increases in K/Na, Ca/Na, and Ca/Mg ratios could mitigate salt stress of the growth habitat of Kosteletzkya virginica. These results suggest that Kosteletzkya virginica is a halophytic species with potential as a rich source of mineral-element supply, and its products could be used for development of food, fodder, health care products and industrial raw materials.     

Single and Combined Effects of Cadmium and Zinc on Carrots: Uptake and Bioaccumulation

ABSTRACT

The present study was conducted to evaluate the effects of different concentrations of cadmium (Cd) and zinc (Zn), singly and in combination, on uptake and bioaccumulation of Cd and Zn in Daucus carota L. (carrot) grown under natural field conditions. Carrot plants were treated with two Cd concentrations (10 and 100 μg mL^?1), two Zn concentrations (100 and 300 μg mL^?1), and two combined concentrations of Cd and Zn (10 + 100 and 100 + 300 μg mL^?1) 15 d after seed germination. Treatments were repeated at 10 d intervals up to 90 d of plant age. A control was also kept without a Cd or Zn treatment. Uptake, total accumulation rate (TAR), bioconcentration factor (BCF), primary transport index (PTI), secondary transport index (STI), and accumulation of Cd and Zn in root, stem, and leaf were quantified. The results show that uptake, TAR, and accumulation of Cd and Zn are concentration-dependent phenomena. Highest accumulation of Cd and Zn was found in the root, followed by the stem and then leaves. The results also showed that bioaccumulation of Cd in root, stem, and leaf was greater at the low metal-application rates of Cd and Zn in combination than at the higher rate. This study further showed that interactions of Zn and Cd are dependent on the concentrations of those metals in the soil.     

Differences in root-to-shoot Cd and Zn translocation and by HMA3 and 4 could influence chlorophyll and anthocyanin content in Arabidopsis Ws and Col-0 ecotypes under excess metals

Judging from the ecotypic variability in Arabidopsis thaliana L., Columbia-0 (Col-0) appears to be less tolerant to cadmium (Cd) than the Wassilewskija (Ws) ecotype that possesses the full-length Heavy Metal ATPase3 (HMA3) cDNA. In this study, the Ws and Col-0 were tested to determine toxic metal response between Ws and Col-0 due to AtHMA3 point mutation and/or other factors. The growth inhibition of Col-0 mediated by Cd and zinc (Zn) was more serious than the inhibition of Ws, while no significant difference was evident by lead (Pb) and cobalt (Co). In the presence of Cd stress, chlorosis in leaves of Col-0 was more serious than the Ws ecotype. When grown under hydroponic culture containing 500?µM Zn, leaves of Col-0 showed a remarkable increase in the anthocyanin content in a dose-dependent manner and the expression of genes encoding enzymes involved in anthocyanin synthesis in the leaves. The rate of root-to-shoot translocation of Cd and Zn in the Col-0 was 2 times higher when compared with the Ws, whereas roots of the Col-0 accumulated 2 times lower Cd and Zn concentrations than those of the Ws. Real-time polymerase chain reaction (PCR) analyses indicated that not only the alteration of the expression of HMA3 but also of the HMA4 was responsible for the root-to-shoot translocation of toxic metals. The results demonstrate that the Col-0 is readily translocating Cd and Zn to the aerial parts but not the Ws, thereby induce the alteration of phenotype in leaf color.     

铝和镉胁迫对两个大麦品种矿质营养和根系分泌物的影响

A hydroponic experiment was carried out to study the effect of aluminum （Al） and cadmium （Cd） on Al and mineral nutrient contents in plants and Al-induced organic acid exudation in two barley varieties with different Al tolerance. Al- sensitive cv. Shang 70-119 had significantly higher Al content and accumulation in plants than Al-tolerant cv. Gebeina, especially in roots, when subjected to low pH （4.0） and Al treatments （100 μmol L^-1 Al and 100 μmol L^-1 Al ＋1.0 μmol L^-1 Cd）. Cd addition increased Al content in plants exposed to Al stress. Both low pH and Al treatments caused marked reduction in Ca and Mg contents in all plant parts, P and K contents in the shoots and leaves, Fe, Zn and Mo contents in the leaves, Zn and B contents in the shoots, and Mn contents both in the roots and leaves. Moreover, changes in nutrient concentrations were greater in the plants exposed to both Al and Cd than in those exposed only to Al treatment. A dramatic enhancement of malate, citrate, and succinate was found in the plants exposed to 100 μmol L^-1 Al relative to the control, and the Al-tolerant cultivar had a considerable higher exudation of these organic acids than the Al-sensitive one, indicating that Al-induced enhancement of these organic acids is very likely to be associated with Al tolerance.     

Cadmium accumulation and distribution in sunflower plant

Cadmium (Cd) accumulation and distribution was studied in sunflower (Helianthus annuus L., public line HA‐89) plant. From an uncontaminated sandy loam brown forest soil with 162 μg kg^‐1 HNO₃/H₂O₂ extractable Cd the HA‐89 sunflower public line accumulated 114 ug kg^‐1 Cd in its kernels under open field conditions. This value is rather low as compared to data found by others. Sandy loam brown forest soil was treated with 0, 1 or 10 mg kg^‐1 of Cd to study the interaction of this heavy metal with young sunflower plants in a greenhouse pot experiment. The fresh weight and dry matter accumulation of sunflower plant organs (roots, shoots, leaves or heads) was unaffected by cadmium treatment of soil. The nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), or zinc (Zn) uptake of sunflower plant organs was not influenced by lower or higher Cd‐doses, except sunflower heads where 10 mg kg^‐1 of Cd treatment of soil significantly reduced the uptake of Ca, Fe, and Mn. Although Cd reduced the Zn uptake of roots, its rate was statistically not significant. Cadmium was accumulated prevalently in roots (1.21 mg kg^‐1,4.97 mg kg^‐1, or 13.69 mg kg^‐1 depending on Cd‐dose), and its concentration increased also in shoots or leaves. In spite of the short interaction time, elevated concentrations of cadmium (0.78 mg kg^‐1, 1.34 mg kg^‐1, or 3.02 mg kg^‐1 depending on Cd‐dose) were detected in just emerged generative organs (heads) of young sunflower plants.     

Cadmium and zinc accumulation in willow and poplar species grown on polluted soils

Woody plant species that produce high biomass have been proposed for use in phytoremediation technology. We investigated the accumulation of cadmium (Cd) and zinc (Zn) in Salix babylonica, S. caprea, S. dasyclados, S. matsudana × alba, S. purpurea, S. smithiana, Populus tremula, and P. nigra clones grown in a pot experiment on a Calcaric and a Eutric Cambisol (pH 7.2 and 6.4) of different levels of contamination (total metal concentrations in mg kg^–1 in soil A: 32.7 Cd, 1760 Zn; soil B: 4.34 Cd, 220 Zn). Generally, the tested clones tolerated large metal concentrations in soils and had larger Cd and Zn concentrations in leaves compared to the roots. The largest Cd concentrations in leaves were found in two clones of S. smithiana (440 mg kg^–1 on soil A; 70 mg kg^–1 on soil B). One of the S. smithiana clones had also the largest Zn concentrations (870 mg kg^–1) on soil B but accumulated slightly less Zn than a S. matsudana × alba clone (2430 mg kg^–1) on soil A. The Cd concentrations in leaves of both S. smithiana clones on soil A are the largest ever reported for soil‐grown willows. The bioconcentration factors of the best performing clone reached 15.9 for Cd and 3.93 for Zn on the less contaminated soil B. Also based on the metal contents in leaves, this clone was identified as the most promising for phytoextraction. The metal concentrations in leaves observed in the pot experiment do not reflect those found in a previous hydroponic study and the leaf‐to‐root ratios are clearly underestimated in hydroponic conditions. This demonstrates the need for testing candidates for phytoextraction crops on soils rather than in hydroponics. Our data also show that the phytoextraction potential should be tested on different soils to avoid misleading conclusions.     

Cadmium,Lead, Copper,Zinc, and Nickel in Lettuce and Dry Beans as Related to Mehlich-3 Extraction in Three Brazilian Latossols

Lettuce (Lactuca sativa L.) and dry beans (Phaseolus vulgaris L.) were grown in three Brazilian Red-Yellow Latossols (Oxisols) in greenhouse conditions with cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), and nickel (Ni) applied to soils in treatments arranged as a randomized complete block design. Plant metals were analyzed in lettuce shoots and dry beans roots, stems, leaves, and seeds. After plant growth, soil samples from the pots were extracted with Mehlich-3 (M-3) for metal availability evaluation. The release of Ni in the M-3 extraction was dependent on the soil exchangeable aluminum (Al^{3 +}). Mehlich-3 was efficient for determination of availability of Cd, Pb, Cu, Zn, and Ni for dry beans and availability of Cd and Ni for lettuce. The dry bean leaves Cd, Pb, Cu, Zn, and Ni were highly correlated with their recovering from soils with M-3. The same was observed for Cd and Ni in lettuce shoots and the M-3 recovered metals from soils.     

Some interactions of cadmium with other elements in plants

Abstract

Cadmium in solution culture at 10^‐4 M decreased Mn concentrations in bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) at both low and high concentrations of Mn (noncompetitive inhibition). When Mn was decreased, the concentrations of Fe and several other ions were simultaneously increased, particularly in leaves and roots. Toxicity due to the 10^‐6 M Cd and the 10^‐4 M Mn was additive in the experiment. When barley (Hordeum vulgare L. Atlas57)was grown in amended soil, 15μg Fe as DTPA (diethylene triamine pentaacetic acid) per g soil resulted in increased uptake of Cd and in somewhat greater yield depression for soil pH of 3.9, 6. 0, and 7.6. Acidification of soil without DTPA also increased Cd uptake to high levels with associated yield decrease. The Cd decreased the uptake of Mn and Cu most when CaCO₃ had also been added to the soil. When salts were added to soil with Cd before bush beans were grown, KCl (200 μg K/g soil), and equivalent KH₂PO₄ increased Cd concentrations of leaves while CaSO₄ and KCl did so for roots. In bush beans with different levels of Cd and Zn, there were no yield interactions, but some interactions of Cd on Zn concentrations in leaves, stems, and roots at the high Zn level.     

Analysis of Some Divalent Metal Contents in Tobacco Expressing the Exogenous Soybean Ferritin Gene

Abstract

T2 tobacco lines overexpressing soybean ferritin in the plastids (+TPs) or apoplasm (AFs) under the regulation of CaMV 35S promoter were grown on MS nutrient solution. After 1 month growth, statuses of six major divalent‐metals (Ca, Cu, Fe, Mg, Mn, and Zn) were measured in leaves and roots. Both +TPs and AFs showed enhanced growth (max. 1.7×) in leaves than the control line. The Fe contents in leaves of +TPs and AFs were significantly larger (1.9–2.8×) than that of the control line. The other metal contents in leaves of +TPs and AFs were almost the same as or less than those of the control line. In contrast to the result of leaves, the growth enhancement in roots was not clear in +TPs, but in AFs. Also, some of the non‐ferrous metal contents in roots of +TPs and AFs were dramatically increased compared with those of the control line (Mn, 1.9–10.4×; Zn, 1.6–2.3×), whereas the differences in content of Fe, Cu, Ca, and Mg were insignificant. These results demonstrated that the ferritin overexpression in apoplasm was as effective for inducing Fe accumulation as that in plastid. Under the normal metal‐balanced condition, even if the activation of Fe uptake related enzymes leads to the accumulation of non‐specific accumulation of divalent metal ions in roots, an Fe loading/unloading system and/or an internal translocator in xylem and phloem might specifically deliver Fe to the upper part of plants.     

Zinc toxicity‐induced variation of mineral element composition in hydroponically grown bush bean plants

Bush bean plants (Phaseolus vulgaris L. cv Contender) were grown for twenty days in nutrient solution (pH=5), containing 0.13, 0.3, 0.5 or 0.75 mg 1^‐1 Zn as ZnSO₄‐7H₂O. The plant yield decreased linearly with the increase of the Zn concentration supplied. The phytotoxic threshold content (for 10% growth reduction) was about 486, 242, 95 and 134^‐ μg Zn g^‐1 for roots, steins, mature primary and trifoliate leaves, and developing leaves, respectively. High inverse correlation coefficients with the Zh concentration supplied were found for the Mn content of all organs, for the P content of roots, and for the Cu and Ca contents of developing leaves. Significant positive relations were found for the Fe, Zn and Cu contents in roots and for the Zn con‐ tents in stems and fully expanded leaves. The ratios of the mineral contents between organs suggest inhibition of uptake of Mn and P, and inhibition of translocation of Fe, Cu and Ca. The relation between dry weight decrease and Zn‐induced nutrient content disorders were discussed.     

Cadmium‐induced alterations in nutrient composition and growth of betula pendula seedlings: The significance of fine roots as a primary target for cadmium toxicity

Birch seedlings (Betula pendula) were cultivated in nutrient solution with 0–2 μM cadmium (Cd). The effects of 2–10 days of Cd exposure on root and shoot element composition [potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), and Cd] and growth (as percentage dry weight increase) were investigated. The element composition of fine roots and remaining root parts were analysed separately to elucidate the significance of the fine roots as a primary target for Cd toxicity. The nutrient composition of the roots was considerably altered by the Cd exposures, whereas the nutrient composition of the shoot was less affected. After eight days, the whole root (fine roots + remaining roots) concentrations of K, Ca, Mg, and Mn were reduced, whereas the opposite was found for Cu and Mo. The element distribution between fine roots and remaining roots was altered by the Cd exposures. Cadmium was accumulated in the roots and in fine roots especially. Fine roots also exhibited a capacity for Cu accumulation and a retainment of Ca and S. Total plant growth was stimulated by 0.05 μM Cd but was reduced by the 0.5–2 μM Cd treatments. Root growth was increased by the Cd exposures and growth reductions were restricted only to the shoot. Accumulation of Cd and Cu and a retainment of Ca and S in the fine roots together with a preference for root growth, imply that the explanation for the Cd effects obtained may include mechanisms for Cd tolerance.     

Foliar application of zinc promotes cadmium absorption by increasing expression of cadmium transporter genes and activities of antioxidative enzymes in winter wheat

Cadmium (Cd) is a deleterious non-essential metal in plants.To elucidate the mechanisms by which zinc (Zn) application alleviates cadmium (Cd)toxicity in wheat,we characterized plant growth,antioxidant system,leaf cell ultrastructure,and Cd transporter gene expression in winter wheat under Cd exposure (50μmol L^-1Cd) with foliar Zn application in a hydroponic experiment.Results showed that Zn addition (Zn+Cd) or pretreatment (pre-Zn+Cd) at 2 g L^-1as Zn SO₄·7H_...     

镉污染土壤伴矿景天的萃取强化-螯合剂和植物激素的叶面调控

为提高Cd超富集植物伴矿景天(Sedum plumbizicola)的植物萃取能力,采用盆栽试验研究螯合剂乙二胺四乙酸(EDTA)和植物激素脱落酸(ABA)单独和联合作用的叶面调控对伴矿景天生长和Cd吸收转运的影响,并通过大田试验进行验证。结果表明:盆栽试验叶面喷施EDTA、ABA均能提高伴矿景天对Cd的转运,地下部至地上部的Cd转运系数为EDTA＞ABA,但叶面EDTA处理对生长旺盛期伴矿景天的生长有抑制。伴矿景天各部位Cd富集浓度差异很大,呈现新叶＞地下部＞茎＞老叶,新叶中Cd浓度是老叶的3.6~5.4倍,且主要富集在细胞壁和细胞器中,占总富集量的88%~94%。EDTA处理新叶细胞器中Cd浓度剧增,ABA处理新叶细胞壁中Cd浓度增加,ABA和EDTA联合使用可以缓解EDTA对生长的抑制,且更有利于Cd从根系向地上部转运。大田小区试验叶面诱导强化伴矿景天Cd萃取是可行的,ABA和EDTA联合处理显著增加伴矿景天总Cd积累量,增幅达到37.87%。研究结果为伴矿景天修复Cd污染土壤提供理论指导。     

Ameliorative Effect of Calcium Nitrate on Cucumber and Melon Plants Drip Irrigated with Saline Water

Abstract

Cucumber (Cucumis sativus cv. Orlando) and melon (Cucumis melo cv. Ananas) were field grown to investigate the effects of supplementary calcium nitrate applied to irrigation water on plant growth and fruit yield of salt stressed and unstressed cucumber and melon plants. Treatments were (1) control: normal irrigation water (C); (2) normal irrigation water plus supplementary 5 mM Ca(NO₃)₂ added to the irrigation water (C + CaN); (3) salt treatment: C plus 60 mM NaCl added irrigation water (C + S); and (4) supplementary Ca(NO₃)₂: C + S plus supplementary 5 mM Ca(NO₃)₂ added to the irrigation water (C + S + CaN). Plants irrigated with water containing high NaCl produced less dry matter, fruit yield, and chlorophyll than the control treatments of both species. Supplementing irrigation water with Ca(NO₃)₂ resulted in increases in dry matter, fruit yield, and chlorophyll concentrations over plants irrigated with saline water. Membrane permeability increased with C + S treatment for both species. Supplementary Ca(NO₃)₂ restored membrane permeability. Sodium (Na) concentration in plant tissues increased in leaves and roots in the elevated NaCl treatment. Concentrations of Ca and N in leaves were decreased in the high salt treatment and fully restored by supplementary Ca(NO₃)₂. These results clearly show that supplementary Ca(NO₃)₂ can partly mitigate the adverse effects of saline water on both fruit yield and whole plant biomass in melon and cucumber plants.     

Synergistic trace metal effects in plants

Abstract

An experiment was conducted in Yolo loam soil with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) with single and combination treatments of moderately high levels of Cd, Li, Cu, and Ni to test whether or not effects could be additive or synergistic. Copper and Ni together were more toxic than either alone. Copper, Ni, and Cd were more toxic together than any one alone. These effects were probably additive and may be related to a 0.2 pH change caused by Cu which increased uptake of Ni and Mn. Synergistic effects were observed in the Cd and Ni concentrations, especially in the stems of the plants. Because of these interactions, the effects were then tested in solution culture. In solution culture with bush beans Cu and Ni when applied together had synergistic effects on plant concentrations of P, Zn, and Fe (all were decreased) and on the Ni concentration in roots. Also, in solution culture with (2.5 × 10^‐5 M) Zn, Cu, and Cd added singly, in pairs, and together, Zn and Cu additively decreased Cd concentrations in roots. Synergistic effects on yield depressions were observed in solution culture for 5 × 10^‐5 M Zn + 3 × 10^‐5 M Cu+ 2 x10^‐5 M Ni. An additive effect on yield depression was observed for 2 × 10^‐4 MCd + 2 × 10^‐5 M Ni. There were many complex interactions among the trace metal concentrations in these plants.