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1.
The effects of Ca(NO3)2 stress on biomass production, oxidative damage, antioxidant enzymes activities and polyamine contents in roots of grafted
and non-grafted tomato plants were investigated. Results showed that when exposed to 80 mM Ca(NO3)2 stress, the biomass production reduction in non-grafted plants was more significant than that of grafted plants. Under Ca(NO3)2 stress, superoxide anion radical (O2•−) producing rate, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents of non-grafted plants roots were significantly higher than those of grafted plants, however,
nitrate (NO3
−), ammonium (NH4
+) and proline contents, superoxide dismutase (SOD, EC1.15.1.1), peroxidase (POD, EC1.11.1.7), catalase (CAT, EC1.11.1.6) and
arginine decarboxylase (ADC, EC 4.1.1.19) activities of grafted plants roots were significantly higher than those of non-grafted
plants. Regardless of stress, free, conjugated and bound polyamine contents in roots of grafted plants were significantly
higher than those of non-grafted plants. The possible roles of antioxidant enzymes, prolines and polyamines in adaptive mechanism
of tomato roots to Ca(NO3)2 stress were discussed.
Gu-Wen Zhang and Zheng-Lu Liu contributed equally to this work. 相似文献
2.
Plants of Miscanthus sinensis (cv. Giganteus) were grown in hydroponics for three months in nutrient solution with 0, 2.2, 4.4 and 6.6 μM CdNO3. Growth parameters, catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and superoxide dismutase (SOD)
activities were analysed in leaves and roots collected after 1-and 3-month exposure. Dry biomass of all miscanthus organs
was affected by Cd concentration both after 1-and 3-month exposure. No visible symptoms of Cd toxicity were observed in shoots
and rhizomes of plants grown in presence of Cd. In contrast, roots became shorter and thicker and the whole root system more
dense and compact already after one month of treatment with 6.6 μM Cd. The lower Cd concentration increased the enzymes activities
after 3 months in leaves and only after 1-month in roots, while a decrease in activity was observed at higher Cd concentrations. 相似文献
3.
The growth and some physiological responses of rice to Cd toxicity as affected by nitrogen form 总被引:1,自引:0,他引:1
Muhammad Jaffar Hassan Muhammad Shafi Guoping Zhang Zhujun Zhu Mahmood Qaisar 《Plant Growth Regulation》2008,54(2):125-132
A hydroponic experiment was conducted to examine the effect of Cd stress on anti-oxidative enzyme activities at heading stage,
yield components, root exudation and Cd and N uptake of rice plants grew in different N source i.e. (NH4)2SO4, NH4NO3 and Ca(NO3)2. The results show that the effect of Cd stress on all measured parameters were N source dependent. Cd stress (1 μM) caused
a remarkable reduction in grain yield and shoot biomass, an increase in root exudation, glutathione content, Cd concentration
and catalase (CAT) and peroxidase (POD) activities of rice plants. In the plants under the control (without Cd addition) N
source had no distinctive effect on the above measured parameters, but the differences among the three N forms in these parameters
became significant when plants were exposed to Cd stress. Cd stress significantly increased POD and CAT activities, and gultathione
content, with Ca(NO3)2-fed plants having the greatest POD and CAT activities and lowest glutathione content, and (NH4)2SO4-fed plants being just opposite. Moreover, organic acid exudation varied also with N form for the Cd-stressed plants. In comparison
with other two N forms, (NH4)2SO4,-treated plants had higher grain yield, N concentration and lower Cd concentration in plants. The current results indicated
that (NH4)2SO4 is a better fertilizer for use in Cd contaminated soil. 相似文献
4.
Hydroponic experiments were carried out to study the role of alginate-derived oligosaccharides (ADO) in enhancing wheat (Triticum aestivum L.) tolerance to cadmium stress. Data were collected on plant biomass, chlorophyll content, photosynthetic rate, antioxidant
enzyme activity and malondialdehyde (MDA) content. Under 100 μM Cd stress, plant growth was significantly inhibited. Shoot
length, root length, fresh and dry weight were sharply reduced by 24.21, 34.59, 22.1 and 14.7%, respectively of the control
after 10 day of Cd exposure. Superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities were increased and
MDA content increased. Wheat seeds were soaked for 5 h in 1,000 mg L−1 ADO solution before cadmium stress. ADO pretreatment alleviated cadmium toxicity symptoms, which were reflected by increasing
root and shoot lengths, fresh and dry weight, chlorophyll content and photosynthetic rate (P
n
). Furthermore, ADO pretreatment significantly increased antioxidant enzyme (SOD, CAT and POD) activities and reduced MDA
content in leaves and roots. The results indicated that ADO pretreatment partially protected the seedlings from cadmium toxicity
during the following growth period. 相似文献
5.
镉诱导的菊芋幼苗膜脂过氧化和抗氧化酶活性及过氧化物酶同工酶的改变 总被引:4,自引:0,他引:4
用含有不同浓度(0~400μmol/L)Cd(NO3)2的Hoagland营养液处理砂培的菊芋。处理50d后,测定植物体内镉积累量以及过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性,并对POD同工酶进行电泳分析。发现在Cd50~100μmol/L浓度内,随着镉浓度的升高,菊芋根和叶中镉的积累量显著增加,而随后积累量的增加有所减少。根和叶中MDA含量显著上升,说明镉引起了膜脂过氧化。0~100μmol/LCd处理,根和叶中POD活性随Cd浓度增加而增强,而在200~400μmol/LCd处理下有所减弱。根和叶SOD活性在50~200μmol/LCd处理下随Cd浓度增加而增强,而在400μmol/LCd处理下SOD活性明显受到抑制。根和叶CAT活性随Cd浓度升高而增强。电泳结果显示,POD同工酶变化明显,镉诱导出一条新酶带LP10。菊芋POD同工酶可以作为镉污染的土壤的生物指示剂。 相似文献
6.
Cadmium accumulation and oxidative burst in garlic (Allium sativum) 总被引:13,自引:0,他引:13
To investigate the temporal sequence of physiological reactions of garlic (Allium sativum) to cadmium (Cd) treatment, seedlings developed from cloves were grown in increasing concentrations of CdCl2, ranging from 1-10 mM, for up to 8 days in sand. Analysis of Cd uptake indicated that most Cd accumulated in roots, but some was also translocated and accumulated in leaves at longer exposure time (after 12h) and higher concentrations (5 and 10mM) of CdCl2. Changes in activities of antioxidative enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were characterized in leaves of garlic seedlings. Cd (5 and 10 mM) initially inhibited the activities of SOD and CAT but thereafter recovered or even increased compared with control plants. POD activities at 5 and 10 mM of Cd increased more than 3-4 times over control plants within 12 h and then dropped, but were still higher than controls at the end of the experiment. Otherwise lipid peroxidation enhanced with the increasing of incubation time and concentrations of external Cd. Leaves exposed to 1 mM CdCl2 showed a less pronounced response and only a small reduction in shoot growth. These results suggested that in leaves of garlic seedlings challenged by CdCl2 at higher concentrations, induction of these various enzymes is part of a general defense strategy to cope with overproduction of reactive oxygen. The possible mechanism of antioxidative enzymes changing before Cd accumulation in leaves of garlic seedlings is discussed. 相似文献
7.
Wheat (Triticum aestivum L. cv. ‘Zyta’) seedlings were treated with 10, 100 and 200 μM Ni. Tissue Ni accumulation, length, relative water content
(RWC), proline and H2O2 concentrations as well as the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol
peroxidase (POD) and glutathione S-transferase (GST) were studied in the shoots and roots after 6 days of Ni exposure. Treatment
with Ni, except for its lowest concentration, resulted in a significant reduction in wheat growth. In comparison to the shoots,
the roots showed greater inhibition of elongation, which corresponded with higher accumulation of Ni in these organs. Both
shoots and roots responded to Ni application with a decrease in RWC and enhancement in proline concentration. Greater dehydration
of the shoot tissue was accompanied by more intense accumulation of proline. Treatment of the wheat seedlings with the highest
concentration of Ni led to about 60% increase in H2O2 concentration in both studied organs. Apart from CAT, constitutive activities of antioxidative enzymes were much higher in
the roots than in the shoots. Exposure of the seedlings to Ni resulted in SOD activity decline, which was more marked in the
roots. While the shoots showed a substantial decrease (up to 30%) in CAT activity, in the roots the activity of this enzyme
remained unchanged. After Ni application APX, POD and GST activities increased several-fold in the shoots, whereas in the
roots they were not significantly altered. The results suggest that differential antioxidative responses of the shoots and
roots of wheat seedlings to Ni stress might be related to diverse constitutive levels of antioxidant enzyme activities in
both organs. 相似文献
8.
Cd胁迫对黄菖蒲幼苗4种抗氧化酶活性的影响 总被引:7,自引:3,他引:4
采用水培法对Cd胁迫下黄菖蒲(Iris pseudacorus L.)幼苗叶片和根系中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)的活性进行了研究。结果表明,10、40和120mg·L^-1Cd胁迫下,黄菖蒲幼苗叶片和根系中4种酶活性的变化不同。10和40mg·L^-1 cd胁迫下,黄菖蒲幼苗叶片和根系中的POD及APX活性、叶片中的SOD活性及根系中的CAT均明显高于对照;在120mg·L^-1 Cd胁迫下,叶片中的POD活性及根系中的POD和CAT活性均高于对照;各处理组根系中的SOD活性均低于对照。随处理时间的延长,40和120mg·L^-1Cd胁迫处理组叶片的CAT活性和120mg·L^-1Cd胁迫处理组根系的APX活性逐渐降低,其他处理组不同酶的活性逐渐升高或先升后降。黄菖蒲叶片及根系中的4种酶对Cd胁迫的响应能力有差异,其中POD可能是黄菖蒲耐Cd胁迫的主要抗性诱导酶。 相似文献
9.
M. Vuletić V. Hadži-Tašković Šukalović K. Marković J. Dragišić Maksimović 《Biologia Plantarum》2010,54(3):530-534
The activities of antioxidative enzymes and contents of proline and total phenolics were assayed in roots of two maize (Zea mays L.) genotypes grown in a medium containing nitrate (NO3
−) or both nitrogen forms, nitrate and ammonium (NH4
+/NO3
−). An increase in the activities of class III peroxidases (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), ascorbate
oxidase (AO) and proline content, and decrease in phenolic content were observed in NH4
+/NO3
− in comparison with NO3
− grown plants. When polyethylene glycol (PEG) was added to both nitrogen treatments, the content of total phenolics and proline
was increased, especially in NH4
+/NO3
− treatment. The PEG treatment decreased enzyme activities in NH4
+/NO3
− grown plants, but in NO3
− grown plants activities of POD and SOD were increased, opposite to decreased APX and AO. Isoelectric focusing demonstrated
increased activities of acidic POD isoforms in PEG treated NO3
− grown plants, and lower activities of both, acidic and basic isoforms in NH4
+/NO3
−grown plants. 相似文献
10.
Cadmium and lead interactive effects on oxidative stress and antioxidative responses in rice seedlings 总被引:7,自引:0,他引:7
Rajneesh Kumar Srivastava Poonam Pandey Ritika Rajpoot Anjana Rani R. S. Dubey 《Protoplasma》2014,251(5):1047-1065
Interactive effects of two heavy metal pollutants Cd and Pb in the growth medium were examined on their uptake, production of reactive oxygen species (ROS), induction of oxidative stress and antioxidative defence responses in Indica rice (Oryza sativa L.) seedlings. When rice seedlings in sand culture were exposed to 150 μM Cd (NO3)2 or 600 μM Pb (CH3COO)2 individually or in combination for 8–16 days, a significant reduction in root/shoot length, fresh weight, relative water content, photosynthetic pigments and increased production of ROS (O2˙? and H2O2) was observed. Both Cd and Pb were readily taken up by rice roots and localisation of absorbed metals was greater in roots than in shoots. When present together in the growth medium, uptake of both the metals Cd and Pb declined by 25–40 %. Scanning electron microscope (SEM) imaging of leaf stomata revealed that Pb caused more distortion in the shape of guard cells than Cd. Dithizone staining of roots showed localisation of absorbed Cd on root hairs and epidermal cells. Both Cd and Pb caused increased lipid peroxidation, protein carbonylation, decline in protein thiol and increase in non-protein thiol. The level of reduced forms of non-enzymic antioxidants glutathione (GSH) and ascorbate (AsA) and their redox ratios (GSH/AsA) declined, whereas the activities of antioxidative enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased in metal treated seedlings compared to controls. In-gel activity staining also revealed increased intensities of SOD and GPX isoforms with metal treatments. Catalase (CAT) activity increased during early days (8 days) of metal exposure and declined by 16 days. Results suggest that oxidative stress is an important component in expression of Cd and Pb toxicities in rice, though uptake of both metals gets reduced considerably when present together in the medium. 相似文献
11.
12.
E. Romanowska B. Wróblewska A. Drożak M. Zienkiewicz M. Siedlecka 《Biologia Plantarum》2008,52(1):80-86
The role of irradiance on the activity of antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) was examined
in the leaves of Pisum sativum L. plants grown under low (LL) or high (HL) irradiance (PPFD 50 or 600 μmol m−2 s−1) and exposed after detachment to 5 mM Pb (NO3)2 for 24 h. The activities of both enzymes increased in response to LL compared with HL and no effect of Pb ions was observed.
Photosystem (PS) 1 and PS 2 activities were also investigated in chloroplasts isolated from these leaves. LL lowered PS 1
electron transport rate and changes in photochemical activity of PS 1 induced by Pb2+ were visible only in the chloroplasts isolated from leaves of LL grown plants. PS 2 activity was influenced similarly by
Pb ions at both PPFD. This study demonstrates that leaves of HL grown plants were less sensitive to lead toxicity than those
from LL grown plants. Changes in electron transport rates were the main factors responsible for the generation of reactive
oxygen species in the chloroplasts and as a consequence, in induction of antioxidant enzymes. 相似文献
13.
Fei Chen Fang Wang Hongyan Sun Yue Cai Weihua Mao Guoping Zhang Eva Vincze Feibo Wu 《Journal of Plant Growth Regulation》2010,29(4):394-408
A greenhouse hydroponic experiment was performed using Cd-sensitive (cv. Dong 17) and Cd-tolerant (Weisuobuzhi) barley seedlings
to evaluate how different genotypes responded to cadmium (Cd) toxicity in the presence of sodium nitroprusside (SNP), a nitric
oxide (NO) donor. Results showed that 5 μM Cd increased the accumulation of O2•−, H2O2, and malondialdehyde (MDA) but reduced plant height, chlorophyll content, net photosynthetic rate (P
n), and biomass, with a much more severe response in the Cd-sensitive genotype. Antioxidant enzyme activities increased significantly
under Cd stress in the roots of the tolerant genotype, whereas in leaves of the sensitive genotype, superoxide dismutase (SOD)
and ascorbate peroxide (APX), especially cytosol ascorbate peroxidase (cAPX), decreased after 5–15 days Cd exposure. Moreover,
Cd induces NO synthesis by stimulating nitrate reductase and nitric oxide synthetase-like enzymes in roots/leaves. A Cd-induced
NO transient increase in roots of the Cd-tolerant genotype might partly contribute to its Cd tolerance. Exogenous NO dramatically
alleviated Cd toxicity, markedly diminished Cd-induced reactive oxygen species (ROS) and MDA accumulation, ameliorated Cd-induced
damage to leaf/root ultrastructure, and increased chlorophyll content and P
n. External NO counteracted the pattern of alterations in certain antioxidant enzymes induced by Cd; for example, it significantly
elevated the depressed SOD, APX, and catalase (CAT) activities in the Cd-sensitive genotype after 10- and 15-day treatments.
Furthermore, NO significantly increased stromal APX and Mn-SOD activities in both genotypes and upregulated Cd-induced decrease
in cAPX activity and gene expression of root/leaf cAPX and leaf CAT1 in the Cd-sensitive genotype. These data suggest that under Cd stress, NO, as a potent antioxidant, protects barley seedlings
against oxidative damage by directly and indirectly scavenging ROS and helps to maintain stability and integrity of the subcellular
structure. 相似文献
14.
Effects of Cadmium on Antioxidant Enzyme Activities in Sugar Cane 总被引:11,自引:0,他引:11
R.F. Fornazier R.R. Ferreira A.P. Vitória S.M.G. Molina P.J. Lea R.A. Azevedo 《Biologia Plantarum》2002,45(1):91-97
Sugar cane (Saccharum officinarum L. cv. Copersucar SP80-3280) seedlings were grown in nutrient solution with varying concentrations (0, 2 and 5 mM) of cadmium chloride for 96 h. Leaves were analysed for catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) activities. Although a clear effect of CdCl2 on plant growth was observed, the activity of SOD was not altered significantly. However, the CAT activity decreased as the concentration of CdCl2 increased. GR exhibits a significant increase in activity at 2 and 5 mM CdCl2. CAT and SOD isoenzymes were further characterised by analysis in non-denaturing PAGE. Activity staining for SOD revealed up to seven isoenzymes in untreated control and 2 mM CdCl2 treated plants, corresponding to Cu/Zn-SOD isoenzymes. At 5 mM CdCl2, only six Cu/Zn-SOD isoenzymes were observed. No Fe-SOD and Mn-SOD isoenzymes were detected. For CAT, one band of activity was observed. 相似文献
15.
Xi-Hua Cui Hosakatte Niranjana Murthy Chun-Hua Wu Kee-Yoeup Paek 《In vitro cellular & developmental biology. Plant》2010,46(5):437-444
The present study investigated the effect of nitrogen source (NH4+; NO3−) at different concentrations on the accumulation of biomass and secondary metabolites in adventitious root cultures of Hypericum perforatum L. Cultures were initiated in shake flasks by using half-strength Murashige and Skoog (MS) medium with B5 vitamins, 1.0 mg l−1 indole-3-butyric acid, 0.1 mg l−1 kinetin, 3% (w/v) sucrose, and different ratios of ammonium and nitrate (0:30, 5:25, 10:20, 15:15, 20:10, 25:5, and 30:0 mM, using NH4Cl and KNO3). The cultures were maintained in darkness. The medium supplemented with 5:25 (mM) NH4+/NO3− resulted in the optimum accumulation of biomass and total phenols and flavonoids. The antioxidant potential of a methanolic
extract, measured as the 1, 1-diphenyl-2-picrylhydrazyl and 2, 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical
scavenging activities, of H. perforatum adventitious roots showed that antioxidant activity was high from root extracts that were grown on higher concentrations
of NO3− nitrogen (15, 20, and 25 mM). Further, assessment of hydrogen peroxide (H2O2) and malondialdehyde content of the root extracts revealed that cultures supplemented with higher levels of NO3− nitrogen (15–30 mM) were under oxidative stress, which boosted the levels of secondary metabolites in the adventitious roots.
These results suggest that optimal adventitious root biomass could be achieved with the supplementation of cultures with 5:25
ratios of MS nitrogen sources. 相似文献
16.
Changes in the elongation of root cells during the negative (away from the salt) or positive (towards the salt) chemotropic bending of roots induced by the unilateral application of agar blocks (1 mm3) with 10–3and 10–2M Cd(NO3)2solutions to the meristem zone of the root were studied. The root bending was not accompanied by differential changes in the number of cells that elongated during the 3-h period of chemical stimulation. The bending was only due to differential changes in the cell elongation rates. In most chemically stimulated roots, both concentrations of Cd(NO3)2solutions inhibited cell elongation at the stimulated and nonstimulated sides. Cell elongation was inhibited by 10–2M Cd(NO3)2mainly on the stimulated side of the roots, hence, the roots bent towards the salt. On the contrary, 10–3M Cd(NO3)2inhibited cell elongation mainly at the nonstimulated side of the roots. As a result, the roots bent away from the salt, i.e., in the direction opposite to that expected in the case of the direct inhibition of cell growth by Cd(NO3)2. It is concluded that the root chemotropisms induced by the above two Cd(NO3)2concentrations are, correspondingly, of a passive or active nature. 相似文献
17.
The effects of lead were investigated in bean plants (Phaseolus vulgaris L. cv. Zlota Saxa) grown hydroponically in nutrient solution and exposed to Pb(NO3)2 (0.1, 0.5, 1 mM) with or without equimolar concentrations of chelator ethylenediaminetetraacetic acid (EDTA). The roots treated
only with Pb(NO3)2 accumulated up to 25 g(Pb) kg−1(d.m.), during 4-d exposure. However, in bean plants exposed to 0.5 mM Pb + 0.5 mM EDTA or 1 mM Pb + 1 mM EDTA 2.5 times less
Pb was determined. In bean plants treated only with Pb, less than 6 % of total lead accumulated was transported to the aboveground
parts, while in the case of plants grown with Pb + EDTA, around 50 % of total Pb was transported to the shoots. 相似文献
18.
This study describes the toxic effects of different prominent aquatic pollutants—heavy metals (Cd & Pb), pesticides (alphamethrin
and deltamethrin) and salt (NaCl)—on the intracellular proline content in the cyanobacterium, Westiellopsis prolifica–Janet strain–NCCU331. Despite a reduction in growth (measured as chlorophyll a content), the intracellular proline content increased in the presence of heavy metals, pesticides and high salt concentration.
The intracellular cyanobacterial proline accumulation was more pronounced under salt stress than in the presence of pesticides
and heavy metals. We have also compared whether or not anionic components influence heavy metal toxicity. It was found that
the chlorides of Cd and Pb were more toxic than the NO3 and the order of toxicity was CdCl2 > PbCl2 > Cd (NO3)2 > Pb (NO3)2. Among pyrethroids, deltamethrin was more toxic than alphamethrin.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
19.
Two 14-day-old seedlings of maize (Zea mays L.) cultivars (3223 and Vero) were exposed to different concentrations of lead [0, 2, 5 and 8 mM Pb(NO3)2·4H2O] for 8 days. Exposure of maize cultivars to excess Pb resulted in a significant root growth inhibition though shoot growth
and absolute water content remained less affected. The results of chlorophyll a fluorescence indicated that the highly toxic Pb level affected photochemical efficiency in 3223, while no significant effect
was observed in the Vero. At the highly toxic Pb concentration, higher membrane leakage was observed in 3223 leaves than that
of Vero. This result was related to the accumulation of Pb. On the other hand, the results suggested that there were similar
responses in total soluble POD and GR activities with increasing Pb concentrations between both cultivars. But APX activity
significantly decreased at highly toxic Pb level in the Vero while a significant increase observed in the 3223. However, SOD
activity in 3223 significantly decreased at the highly toxic Pb concentration compared with that at 2 mM Pb concentration.
The results of the present study indicated that, Vero withstands excess Pb with its higher Pb accumulation capacity in roots
and better upregulated protective mechanisms compared to 3223. Therefore, Vero is more tolerant to Pb toxicity compared to
3223 which was found to be a less tolerant cultivar. 相似文献
20.
Silicate-Mediated Alleviation of Pb Toxicity in Banana Grown in Pb-Contaminated Soil 总被引:4,自引:0,他引:4
Silicate (Si) can enhance plant resistance or tolerance to the toxicity of heavy metals. However, it remains unclear whether
Si can ameliorate lead (Pb) toxicity in banana (Musa xparadisiaca) roots. In this study, treatment with 800 mg kg−1 Pb decreased both the shoot and root weight of banana seedlings. The amendment of 800 mg kg−1 Si (sodium metasilicate, Na2SiO3·9H2O) to the Pb-contaminated soil enhanced banana biomass at two growth stages significantly. The amendment of 800 mg kg−1 Si significantly increased soil pH and decreased exchangeable Pb, thus reducing soil Pb availability, while Si addition of
100 mg kg−1 did not influence soil pH. Results from Pb fractionation analysis indicated that more Pb were in the form of carbonate and
residual-bound fractions in the Si-amended Pb-contaminated soils. The ratio of Pb-bound carbonate to the total Pb tended to
increase with increasing growth stages. Treatment with 100 mg kg−1 Si had smaller effects on Pb forms in the Si-amended soils than that of 800 mg kg−1 Si. Pb treatment decreased the xylem sap greatly, but the addition of Si at both levels increased xylem sap and reduced Pb
concentration in xylem sap significantly in the Si-amended Pb treatments. The addition of Si increased the activities of POD,
SOD, and CAT in banana roots by 14.2% to 72.1% in the Si-amended Pb treatments. The results suggested that Si-enhanced tolerance
to Pb toxicity in banana seedlings was associated with Pb immobilization in the soils, the decrease of Pb transport from roots
to shoots, and Si-mediated detoxification of Pb in the plants. 相似文献