全 文 ：植 物 学 报
Acta Botanica Sinica 2003, 45 (9): 1030-1036 http://www.chineseplantscience.com
Received: 2002-12-02 Accepted: 2003-04-16
Supported by the National Natural Science Foundation of China (20277035) and the State Key Basic Research and Development Plan of China
(2002CB410804).
* Author for correspondence. E-mail: .
Growth Response and Metal Accumulation of Sedum alfredii
to Cd/Zn Complex-Polluted Ion Levels
YE Hai-Bo1, YANG Xiao-E1*, HE Bing1, 2, LONG Xin-Xian1, SHI Wei-Yong1
（1.College of Natural Resources and Environmental Sciences, Zhejiang University, Hangzhou 310029, China;
2. College of Agriculture, Guangxi University, Nanning 530005, Ch na)
Abstract: Sedum alfredii Hance has been identified as a new Zn-hyperaccumulator native to China. In
this study, responses and metal accumulation of S. alfredii were exa ined u der Zn/Cd complex polluted
conditions. The results showed that optimal growth of S. alfredii in terms of the maximum dry matter yield
was observed at Zn/Cd complex level of 500/100 祄ol/L. Plant cadmium (Cd) or zinc (Zn) concentrations
increased with increasing Cd or Zn supply. During the 20 d treatment, the highest Cd concentration in the
leaves reached 12.1 g/kg at Zn/Cd level of 50/400 祄ol/L and that of Zn in the stems was 23.2 g/kg at
Zn/Cd level of 1 000/50 祄ol/L. The distribution of Cd in different plant parts decreased in the order: leaf
＞ stem≥ root, whereas that of Zn was: stem ＞ leaf ≥ root. The accumulation of Cd and Zn in the
shoots and roots of S. alfredii increased with the increasing of Zn/Cd supply levels, peaked at Zn/Cd levels
of 250/400 and 500/100 祄ol/L, respectively. The highest Cd and Zn uptake by the shoots was approxi-
mately 5 and 11 mg/plant, and was over 20 and 10 times higher than those in the roots, respectively. Zn
supply at levels ≤ 500 祄ol/L increased plant Cd concentrations, whereas high Zn supply decreased root
Cd but did not affect leaf Cd concentrations in S. lfredii. Low Cd supply increased Zn concentration in the
leaves, but Cd supply higher than 50 祄ol/L consider bly reduced root Zn concentrations, especially at
low Zn level. These results indicate that S. alfred i can tolerate igh Zn/Cd complex levels and has an
extraordinary ability to hyperaccumulate not only Zn but also Cd. It could provide a new valuable plant
material for understanding the mechanisms responsible for co- yperaccumulation f Zn and Cd as well as
for phytoremediation of the Cd/Zn complex polluted soils.
Key words: complex pollution; cadmium (Cd); zinc (Zn); hyperaccumulation; Se um alfredii
Heavy metals contamination of surface soil is prevalent
at many industrial and mining sites throughout the world,
their toxic effects on the biological organisms, especially to
human beings through food chain, have been drawn great
attention, and the remediation of the metal polluted soil has
become the hot and difficultly scientific issues in the world.
Cadmium (Cd) is one of the most toxic heavy metals for
environment due to its high mobility and low toxic concen-
tration in organism. In China, large areas of the soils have
been polluted by heavy metals such as Cd, mercury (Hg),
lead (Pb), zinc (Zn), etc. (Yang et al., 2002), among which Cd
pollution was most widespread (Wang, 1997). Zn is an es-
sential plant micronutrient, but can be highly toxic when
present at large concentrations. Cd and Zn are elements
having similar geochemical and environmental properties,
since Zn ores normally contain 0.1%-5% of Cd, the pro-
cessing and subsequent release of Zn to the environment
is normally accompanied by Cd environmental pollution.
Phytoextraction is a new emerging technique to clean up
heavy metal polluted soils using metal hyperaccumulators.
The basic strateg es of th phytoextraction are growing the
accumula ing plan s on the polluted soils to remove heavy
metals by pl t uptake and successive harvesting the plants
(Salt et al.,1995; Adriano et al., 1997; Long et al., 2002). The
success of phytoextraction argely depends upon the iden-
tification of suitable plant species that must be fast growing,
have high biomass, be easy to harvest and should tolerate
and accumulate a range of heavy metals in their aerial parts.
To d te, no plant has been described to meet all these crite-
ria (Clemens et l., 2002).
S. alfredii has been identified as a new Zn-
hyper ccumulator nat ve to China (Yang et al., 2002). It has
characteristics of large biomass, fast growth and easy
propagatio .S. alfredii showed no visible symptoms of metal-
i uced toxicity when exposed to 3 671 mmol Zn/L ( Long et
al., 20 2), and the highest Zn concentration in shoots reached
20 g/kg（Yang et al.，2002）. Recently, we also found
the exceptio al y high tolerance of S. a fredii to Cd, both in
t ms of solution Cd level and tissue Cd concentration. The
maximum concent tions of Cd reached 8 g/ kg in leaves and
Abstract: Sedum alfredii Hance has been identified as a new Zn-hyperaccumulator native to China. In
this study, responses and metal accumulation of S. alfredii were ex m ned under Zn/Cd complex polluted
conditions. The results showed that optimal growth of S. alfredii in ter s of the maximum dry matter yield
was observed at Zn/Cd complex level of 500/100 μo /L. Plant cadmium (Cd) or zinc (Zn) concentrations
increased with increasing Cd or Zn supply. During the 20 d treatment, the highest Cd concentration in the
leaves reached 12.1 g/kg at Zn/Cd level of 50/400 μmol/L and that of Zn in the stems was 23.2 g/kg at
Zn/Cd level of 1 000/50 μmol/L. The distribution of Cd in different plant parts decreased in the order:
leaf ＞ stem≥ root, whereas that of Zn was: stem ＞ leaf ≥ root. The accumulation of Cd and Zn in the
shoots and roots of S. alfredii increased with the increasing of Zn/Cd supply levels, peaked at Zn/Cd
levels of 250/400 and 500/100 μmol/L, respectively. The highest Cd and Zn uptake by the shoots was
approxi-mately 5 and 11 mg/plant, and was over 20 and 10 times higher than those in the roots,
respectively. Zn supply at levels ≤ 500 μmol/L increased plant Cd concentrations, whereas high Zn supply
decreased root Cd but did not affect leaf Cd concentrations in S. alfredii. Low Cd supply increased Zn
concentration in the leaves, but Cd supply higher than 50 祄ol/L considerably reduced root Zn concentrations,
especially at low Zn level. These results indicate that S. alf dii can tolerate high Zn/Cd complex levels
and has an extraordinary ability to hyperaccumulate not only Zn but also Cd. It could provide a new
valuable plant material for understanding the mechanisms responsible for co-hyperaccumulation of Zn and
Cd as well as for phytoremediation of the Cd/Zn complex polluted soils.
YE Hai-Bo et al.: Growth Response and Metal Accumulation of S dum alfredii to Cd/Zn Complex-Polluted Ion Levels1031
5.6 g/kg in stems grown at 200 m ol Cd/ L, at which no
reduced shoot and root dry matter yields were observed
(Yang et al., 2003). Studies on the interaction between Cd
and Zn conducted so far focused on the conventional plant
species, and some authors suggested that interactive pat-
tern was antagonistic, whereas others argued that it was
synergistic (Piotrowska et al., 1994; Xu et al., 2001). Little
information is available about the Cd-Zn interaction in the
hyperaccumulator. The objectives of this study were to
examine the responses of S. alfredii to Cd/Zn complex lev-
els and the potential physiological mechanism involved in
Cd/Zn accumulation and interaction in the plant.
1 Materials and Methods
1.1 Plant culture
The plant materials of Sedum fredii Hance were ob-
tained from an old Pb/Zn mining area in Zhejiang Province,
China. Healthy and equal-sized stems were chosen and
grown in the basic nutrient solution with the composition:
(in mmol/L) 2.00 Ca(NO3)2?H2O, 0.10 KH2PO4, 0.50
MgSO4?H2O, 0.10 KCl, 0.70 K2SO4, and (in 祄ol/L) 10.00
H3BO3, 0.50 MnSO4稨2O, 0.50 ZnSO4?H2O, 0.20
CuSO4?H2O, 0.01 (NH4)6Mo7O24, 100 Fe-EDTA. The plants
were precultured in the nutrient solution for 30 d to estab-
lish new root system prior to the metal treatment. The treat-
ments were composed of control and the complex Zn/Cd
supply levels with Zn and Cd levels of 50, 250, 500, 1 000
and 25, 50, 100, 400, (mmol/L), respectively. Zn and Cd were
applied as sulfate and chloride, respectively. Each treat-
ment was replicated three times and each container had 18
plants. The nutrient solution was aerated 24 h and replaced
every 4 d. The solution pH was maintained at 5.5 adjusted
daily with 0.1 mol/L HCl or 0.1 mol/L NaOH. Plants were
harvested after exposed to the metal treatment for 20 d.
Roots were washed with tap water, and immersed in 20
mmol/L Na2-EDTA (disodium ethylenediaminetetraacetate)
for 15 min to remove Cd and Zn adhering to root surfaces
(Yang et al., 1996). The plants (leaves, stems and roots)
were rinsed with deionized water, blotted dried, and oven
dried at 70 oC. Fresh and dry weights were recorded.
1.2 Chemical analysis
The dried plant materials were ground with stainless
steel mill and passed through 0.25 mm sieve for elemental
analysis. The ground plant samples were digested with
concentrated acid mixture (HNO3 : HClO4, 5:1) at 200-220
℃ (Zhao et al.,1994). The Cd and Zn concentrations in the
digested solution were analyzed using a flame atomic ab-
sorption spectrophotometer (AA6800, Shimadzu).
Analysis of variance (ANOVA) was performed on all
the data sets. The least significant different (LSD) was used
for mult p e comparison between treatment means. The sta-
tistical analysis for the data was performed using a statisti-
cal package (SPSS10.0).
2 Results
2.1 Effects of Cd/Zn complex levels on plant growth
The plants of S. alfredii showed visible symptoms of
Cd toxici y grown at 400祄ol Cd/L. Th stunted plant,
deform d top leaves were observed at Zn/Cd complex lev-
els of 1 000/400 祄ol/L. The dry weights of leaf, stem and
root increas d with increasing Cd supply levels grown at
Zn levels≤500 祄ol/L, and the max dry weight of shoot
and root were obtained at the Zn/Cd complex level of
500/100 祄ol/L (Table 1). High Zn (1 000 祄ol/L) decreased
the dry matter yields of leaf, stem, and root when grown at
the Cd supply levels≤100祄o /L. At the Cd level of 400
祄ol/L, however, t e dry weight of stems was not signifi-
cantly affected whereas root growth was slightly increased
by the elevated Zn supply levels (Table 1). These results
show that S. lfredii is very tolerant of Zn/Cd complex
toxicities, and exhibits an optimal plant growth at the
Zn/Cd complex level of 500/100 in nutrient solution.
2.2 Effects f Cd/Zn complex levels on Cd concentration
Cd concen ations in the l f, stem, and root of S. alf dii
increased with increasing Cd supply levels in the solution.
Raising Zn levels from 50 to 1 000 祄ol/L enhanced Cd
conce trations of S. alf dii when grown at Cd≤100
祄ol/L for stems, and leav s, and at Cd <50 祄ol/L for
roots (Tabl 2). At high Cd (400 祄ol/L), Zn treatment did
ot ignificantly ffect Cd concentrations in the leaves,
ste s, and roots. The highest concentrations of Cd in the
leaf, stem, and root reach d 12.1, 7.4, and 2.9 g/kg,
respectively. At the Zn/Cd complex levels of 500/100 祄ol/L,
the optimal plant growth was obtained and Cd concentra-
tions in the leaf and stem reached 6.27 and 3.93 g/kg,
respectively. These results indicate that Zn has a positive
effect on Cd uptake by the root and translocation to the
shoot at Cd levels till 100 祄ol/L. The lea s appeared to
contain the highest Cd, followed by stem, and the roots
have far lower Cd concentration. The results demonstrated
thatS. alfre ii has an extraordinary ability to accumulate
Cd in the shoots, especially in the leaves.
2. 3 Effects of Cd/Zn complex levels on Zn concentration
Zn concentrations in the leaves were not affected, but
those in he tems and roots were lowered by Cd supply at
Zn ≥ 500 and ≥ 25祄ol/L r spect vely (Table 3). The
maximum leaf Zn concentration was 22.4 g/kg grown at he
Zn/Cd complex l vel of 1 000/100 祄ol/L, whereas the
1032 植物学报 Acta Botanica SinicaVol.45 No.9 2003
highest Zn concentrations in the stems and the roots
reached 23.2 and 17.47 g/kg at Zn/Cd level of 1 000/50 and
1 000/25 祄ol/L, respectively. Root Zn concentration dra-
matically reduced by the increased Cd levels, especially
when the plants were grown at low Zn supply. For instance,
at 50 mmol Zn/L, root Zn concentration decreased for 4-fold
when Cd levels increased from 25 to 400 祄ol/L (Table 1).
These results show that the effect of Cd on Zn absorption
varies with supply levels of Zn or Cd and plant tissues, and
high Cd enhances Zn translocation to the leaves.
2.4 Effects of Cd/Zn complex levels on Cd and Zn accu-
mulation
Cd accumulation in the shoots and roots strikingly
increa ed with incr asing Cd supply, and the interaction
between Cd and Zn had a marked effect on Cd accumula-
io (Fig.1). H gh Zn supply (1 000 祄ol/L) decreased Cd
accumulation in the shoots at each Cd level and in the
roots at Cd level ≥50祄o /L (Fig.1). Addition of Zn at
levels till 500祄o /L nhanced Cd accumulation in the
shoots when exposed to solution Cd levels≥100 祄ol/L.
The highest Cd accumulated in the shoots was 4.9 mg
Cd/plant t Zn/C complex level of 250/400 祄ol/L, and
was approximat ly 25-fold higher than that in the roots.
What is more, was almost entirely translocated to shoots
(95%) against a very small amount (5%) retained in roots.
These results indicate that S. alfredii has a strong ability
Table 2 Effects of Zn/Cd complex levels on Cd concentrations (g/kg) in leaves, stems, and roots of Sedum alfredii
Zn levels Leaf Stem Root
(祄ol/L) Cd1 Cd2 Cd3 Cd4 Cd1 Cd2 Cd3 Cd4 Cd1 Cd2 Cd3 Cd4
50 2.783.805.6512.1 2.48 2.32 3.24 7.440.48 0.46 1.26 2.90
250 3.374.806.4611.6 2.95 2.54 3.58 6.980.66 0.91 0.99 2.73
500 4.205.406.2712.1 3.15 3.05 3.93 6.870.70 0.99 1.09 2.54
1 000 4.045.067.1411.4 2.35 2.83 3.99 6.530.78 1.01 1.17 2.49
ANOVA17.00** 22.00** 4.10* 0.6722.00** 9.00** 15.00** 3.3011.00** 76.00 ** 5.774* 0.95
LSD0.05 0.510.480.99 1.38 0.26 0.34 0.30 0.680.12 0.10 0.15 0.62
LSD0.01 0.740.701.44 2.01 0.39 0.50 0.43 0.980.18 0.14 0.22 0.90
Cd concentrations in the leaves, stems and roots of the control are 0.081, 0.662, and 0.055 g/kg, respectively. Cd1, Cd2, Cd3, and Cd4 denote
25, 50, 100, and 400 祄ol Cd/L, respectively; * and ** indicate significance at level of P<0.05 ndP<0.01, respe tiv ly; ANOVA stands for
analysis of variance.
Table 1 Effects of Zn/Cd complex levels on dry matter yields (g/plant) of leaves, stems, and roots of Sedum alfredii
Zn levels Leaf Stem Root
(祄ol/L) Cd1 Cd2 Cd3 Cd4 Cd1 Cd2 Cd3 Cd4 Cd1 Cd2 Cd3 Cd4
50 0.26 0.350.26 0.25 0.14 0.19 0.20 0.120.0650.080.0840.052
250 0.25 0.310.32 0.32 0.13 0.18 0.17 0.170.0560.0710.0790.076
500 0.28 0.330.38 0.27 0.16 0.16 0.22 0.150.0680.0830.0910.075
1 000 0.18 0.190.21 0.19 0.14 0.13 0.14 0.150.050.0550.0570.066
ANOVA22.00** 14.00** 10.00** 20.00** 2.70 4.60* 2.80 3.603.6705.873* 1.6275.149*
LSD0.05 0.05 0.070.07 0.04 0.02 0.04 0.07 0.030.0140.0170.0520.016
LSD0.01 0.07 0.100.11 0.06 0.03 0.06 0.10 0.050.0210.0250.0750.023
Dry matter yields of leaves, stems and roots in the control are 0.28, 0.15, and 0.097 (g/plant). Cd1, Cd2, Cd3, and Cd4 enote 25, 50 100, and
400 祄ol Cd/L, respectively; * and ** indicate significance at level of P<0.05 ndP<0.01, respectively; ANOVA stands for analysis of
variance.
Table 3 Effects of Cd/Zn complex levels on Zn concentrations (g/kg, in the leaves, stems, and roots of Sedum alfredii
Zn levels Leaf Stem Root
(祄ol/L) Zn1 Zn2 Zn3 Zn4 Zn1 Zn2 Zn3 Zn4 Zn1 Zn2 Zn3 Zn4
25 10.2016.319.822.313.817.6 21.221.9 4.45 7.1411.3417.47
50 11.3017.319.721.313.717.8 20.523.2 3.96 7.4211.7716.34
100 10.8018.018.622.412.918.3 19.421.4 2.00 7.43 8.8911.64
400 12.8017.018.020.612.916.4 17.717.9 0.93 5.43 7.2110.04
ANOVA F3.96 3.1 3.1 2.0 1.6 4.1* 2.3 13.0* 71.00** 4.90* 7.70* 34.00**
LSD0.05 1.80 1.3 1.7 1.9 1.4 1.3 3.0 2.0 0.63 1.41 2.52 2.00
LSD0.01 2.60 1.9 2.4 2.7 2.0 1.9 4.3 2.9 0.93 2.05 3.67 2.91
Zn concentrations in the leaves, stems and roots of the control are 2.79, 6.29, and 1.16 g/kg, respectively. Zn1, Zn2, Zn3 , and Zn4 de ot 50,
250, 500, and 1 000 祄ol Zn/L, respectively; * and ** indicate significance at level of P<0.05 ndP<0.01, respe tiv ly; ANOVA stands for
analysis of variance.
YE Hai-Bo et al.: Growth Response and Metal Accumulation of S dum alfredii to Cd/Zn Complex-Polluted Ion Levels1033
for transporting Cd from the root to the shoot.
Zn accumulation in shoot and root significantly in-
creased with increasing Zn supply and Cd treatments have
a remarkable effect on it (Fig.2). Application of Cd at level
≤ 100 祄ol/L increased Zn accumulation in the shoots and
the roots when grown at Zn levels ≤500 祄ol/L, but high
Cd (400 祄ol/L) reduced Zn accumulation, especially in the
roots at the low Zn level (Fig.2). The highest Zn accumu-
lated in the shoots was 11.2 mg/plant at the Zn/Cd complex
level of 500/100 祄ol/L and was over 12-fold greater than
that in the roots. Shoot contained more than 90% of total
Zn taken up by the plant. These results imply that Cd sup-
ply at low levels enhanced Zn absorption and transloca-
tion when grown at 500 祄ol/L Zn, high Cd treatment in-
hibits Zn absorption by root, but does not affect Zn trans-
location to the shoots.
3 Discussion
A number of enzymes in the plant are activated by Zn,
and Cd displacement for Zn from the functional sites of the
enzymes in cells inactivates the enzymes due to their
similar electron configuration on the outer shells. Addition
of Zn usually inhibits Cd uptake due to the Cd-Zn compe-
tition an reduc d Cd toxicity in different crop plants (Li et
al., 1990). The effects of Zn on reducing Cd toxicity may
also result from the stimulated synthesis of the compounds
by Zn rich in sulphydryl group that can combine Cd with
high affinity (Wagner, 1985; Toppi and Gabbrielli, 1999).
However, ot er researcher argued that Cd toxicity was en-
hanced by dded Zn (Piotrowska et al., 1994). The results
from this study indicate that the interaction between Zn
and C on the growth he hyperaccumulating plant spe-
ci s largely depends on Zn/Cd supply levels and plant
part . The optimal growth ofS. frediiw s observed at
the Zn/Cd complex level of 500/100 祄ol/L (Table 1). Higher
Zn or Cd supply r duced oot and stem growth to some
extent. Addition of Cd at proper levels can alleviate Zn
toxicity and similarity was found for the Cd toxicity allevi-
ated by supplied Zn at proper levels.
The Cd con entration in S. alfredi d creased in the
order o leaf > stem > ro t, whereas the Zn concentration
changed in the order of stem > leaf > root (Tables 2, 3). At
Fig.2. Effects of Cd /Zn complex levels on Zn accumulation in the shoots (a) and roots (b) f S. alfredi.
Fig.1. Effects of Cd /Zn complex levels on Cd accumulation in the shoots (a) and roots (b) f S. alfredii.
1034 植物学报 Acta Botanica SinicaVol.45 No.9 2003
relatively low Cd (<50 祄ol/L), Zn supply enhanced root
absorption and root to shoot translocation of Cd. However
Cd supply levels higher than 50 祄ol/L inhibi ed Zn ab-
sorption by the root but did not affect Zn translocation to
the leaves. These results imply that metal absorption and
transport in S.alfredii may be controlled by different
mechanisms. Nan et al. (2002) found Cd accumulation in
the wheat and corn was enhanced by Zn. The results from
this study demonstrate that Zn supply at proper levels stimu-
lated Cd uptake and translocation to the shoot, which may
be due to the facts that ion/H+ n iport, ATP-dependent
PC-transporter, and/or metal transporters have been in-
duced by the added Zn (Salt and Rauser, 1995; Lasat et al.,
1996). Recently, Lasat t al. (2000) have cloned a high-
affinity Zn transporter (named ZNT1) tha is over expressed
in Thlaspi caerulescens, and demonstrated that ZNT1 me-
diates Zn uptake as well as that of Cd uptake with a much
lower affinity. However, Zn supply could not increase Cd
concentration when the plants were grown at 400 祄o
Cd/L, which may result from the competitive transport and
absorption interactions between these two ions
(Gussarsonn et al., 1995). Root Zn considerably decreased
by application of Cd higher than 100 祄ol/L, w ich m y be
explained by their competition for the same carrier, but Zn
translocation to the leaf was slightly increased or not af-
fected by Cd levels. The positive effect of Cd on Zn trans-
location from the root to the leaf may be partly resulted
from the displacement of Cd for Zn from sorption sites of
the cell wall, this could be relative to electronegative charges
of the cell walls (Xu et al., 2001). It has been found that S.
alfredii has great demand for Zn in its life cycle (Long et
al., 2002). When the plants were grown at 400 祄ol/L, phy-
totoxicity symptoms similar to Zn deficiency was observed
although the Zn concentration in plant far exceeded that
for conventional species. Cd can activate the synthesis of
phytochelatins in order to tolerate Cd, and this detoxifica-
tion mechanism may also lower plant Zn bioavailability
(Shen et al., 1997). Therefore, Zn-Cd interaction in the
hyperaccumulating plant species is different from that in
normal crop plant species, and strong positive interaction
of Zn and Cd occurs at proper Zn/Cd complex levels.
Generally, leaf Zn level in excess of 300-600 mg/kg dry
weight is considerable toxic to plants (Piotrowska et al.,
1994; Long et al., 2003). For normal crop plant species,
foliar Cd concentration above 1 mg/kg is usually consid-
ered to be toxic and root contained 70%-90% f total Cd in
the plant (Toppi and Gabbrielli, 1999). However, the high-
est Cd (12 000 mg/kg) and Zn (22 000 mg/kg) concentra-
tions were observed in the shoot part of S. alfr dii grown
at Zn/Cd levels of 50/400 and 1 000/50 祄ol/L, respectively
(Tables 2, 3). The ratios of leaf/root or stem/root concentra-
tion exceed 1 for both Cd and Zn. The shoots contained
over 95% of the total metal aken up by the plant. These
results show that S. alfredii is another Zn/Cd-
hyperaccumula or after T. caerulescens (Baker t al.,1994;
Brown et a ., 1995; Knight et al., 1997; Lombi et al., 2001).
T. caerulescensgrows as a small basal rosette up to 15 cm,
it is impractical to harve rosette type plants with mechani-
cal equipment. In comparison to T. caerulescens, S. alfredii
has its characteristics of fast growth, large biomass, asexual
rep oduction. It is p rennial plant, can propagate for 3-4-
fold in a year if the environmental conditions are favorable
to its growth and can cover the land surface nearly 100%
(Yang et al.，2002). Our field experiments demonstrated
that S. alfredii could produce shoot dry matter yield as
high as 3 000 kg/hm, and a cumulate Zn and Cd in the
hoots as high as 20 000 and 300mg/kg (DW) whe grown
at the complex metal contaminated paddy soil contained
otal contents of Zn and Cd approximately 2 000 and 20
mg/kg soil, respec ively (unpublished data). All these re-
sults demonstrate that S. alfr ii has a greater potential for
its application to the large-scale phytoremediation in com-
plex heavy metal polluted soils. The mechanisms respon-
ible for Cd-Zn interaction and hyperaccumulation need to
be further investigated.
Acknowledgements: Th u hors wish to thank Dr. YE
Zheng-Qian, assoc ate professor of Zhejiang University,
for his useful commen s and g ammatical revision of this
article.
References:
Adriano D C, Wenzel W W, Blum W E H. 1997. Role of
phytoremediation in the est blishment of a global soil
remediation network. Proceedings of International Seminar
on Use Plants for Environment Remediation. Kosaikaikan,
Tokyo, Japan. 3-25.
Baker A J M, Reeves R D, Hajar A S M. 1994. Heavy metal
accumulation and tolerance in British populations of the
me allophyte Thlasp caerulescens J & C Presl. N w Phyt l,
127:83-92.
Brown S L, Chaney R L , Angle J S, Baker A J M. 1995. Zinc and
cadmium uptake by hyperaccumulator Thlaspi caerulescens
grown in nutrient solution. So l Sci Soc Am J,59:125-133.
Clemens S, Plamgren M G, Kr鋗er U. 2002. A long way ahead:
un erstanding and engineering plant metal accumulation.
Trends Plant Sci, 7:309-316.
Gussarson M, Adalsteinsson S, Jensen P, Asp H. 1995. Cad-
mium nd Copper interaction on the accumulation and
YE Hai-Bo et al.: Growth Response and Metal Accumulation of S dum alfredii to Cd/Zn Complex-Polluted Ion Levels1035
(Managing editor: HAN Ya-Qin)
distribution of Cd and Cu in birch (Betula pendula Roth)
seedlings. Plant Soil,171:185-187.
Knight B, Zhao F J, Mcgrath S P. 1997. Znic and cadmium
uptake by the hyperaccumulator Thlaspi caerulescens in
contaminated soils and its effects on the concentration and
chemical speciation of metals in soil solution. Plant So l,
197:71-78.
Lasat M M, Baker A J M, Kochian. 1996. Physiological Char-
acterization of root Zn2+ abso ption and translocation to
shoots in hyperaccumulator and non-hyperaccumulator spe-
cies of Thlaspi . Plant Physiol, 112:1715- 722.
Lasat M M, Pence N S, Garvin D F, Ebbs S D, Kochian L V.
2000. Molecular physiology of zinc transport in the Zn
hyperaccumulator Thlaspi caerulescens. J Exp Bot, 51:71-
79.
Li S-L (李森林), Wang H-X (王焕校), Wu Y-S (吴玉树). 1990.
Antagonistic effects of zinc on cadmium in waterhyacinth.
Acta Sci Circumstantiae (环境科学学报), 10:244-249. (in
Chinese with English abstract)
Lombi E，Zhao F J, Mcgrath S P. 2001. Physiological evi-
dence for a high-affinity cadmium transporter highly ex-
pressed in a Thlaspi caerulescens. New Phytol, 149:1-8.
Long X-X (龙新宪), Yang X-E (胡肖娥), Ye Z-Q (叶正钱), Ni
W-Z (倪吾钟), Shi W-Y (石伟勇). 2002. Differences of up-
take and accumulation of znic in four species of Sedum. Acta
Bot Sin (植物学报), 44:152-157.
Long X X, Yang X E, Ni W Z, Ye Z Q, He Z L, Calvert D V,
Stoffella P J. 2003. Assessing zinc thresholds for phytotox-
icity and potential dietary toxicity in selected vegetable crops.
Commun Soil Sci Plant Anal, 34(in press).
Nan Z R, Li J J, Zhang J M, Cheng G D. 2002. Cadmium and
zinc interactions and their transfer in soil-crop system under
actual field conditions. S i To al Environ, 285:187-195.
Piotrowska M, Dudka S, Chlopecka A. Effect of elevated con-
centrations of Cd and Zn in soil on spring wheat yield and
metal contents of the plants. Water Air Soil Pollut, 1994, 76:
333- 41.
Salt D E, Blaylock M, Kumar N P B A, Vitatcheslar D, Ensley B
D. 1995. Phytoremediation: a novel strategy for the removal
of toxic metals from the environment using plant. Bio-Technol,
13:468-474
Salt D E, Rauser W E. 1995. MgATP-dependent transport of
phytochelati s ac oss the tonoplast of oat roots. Plant
Physiol, 107:293-301.
Shen Z G, Zhao F J, Mcgrath G. 1997. Uptake and transport of
Znic in t e hyperaccumul tor Thl spi caerulescens and the
on-hyperaccumulator Thlaspi ochr leucum.Plant Cell
Environ, 20:898-906.
Toppi L, Gabbrielli R. 1999. Response to cadmium in higher
plants.Environ Exp Bot,44:105-130.
Wagner G J. 1985. Characterization of a cadmium-binding com-
pound of cabbage leaves. Pl nt Physiol, 76:797-805.
Wang K-L (王凯荣).1997. Situation of the Cadmium Contami-
nated Croplands in China and countermeasure of Remediating
or us ng them. Agro-envi on Pro ect (农业环境保护), 16:
274-278. (in Chinese with English abstract)
Xu G-L (许桂莲)，Wang H-X (王焕校), Wu Y-S (吴玉树),
Wang G-C (王光灿)，Zhu G-H (朱光辉). 2001. Effect
of Zn, Cd and their combined on Ca, Fe and Mn uptake by
wheat seedlings. Chin J Appl Ecol(应用生态学报)，12：
275-278. (in Chinese with English abstract)
Yang X E, Long X X, Ni W Z. 2002. A new zinc hyperccumulating
plant species native to China. Chin Sci Bull, 47:1003- 6.
Yang X E, Long X X, Ye H B, He Z L, Calvert D V, Stoffella P
J. 2003. Cadmium tolerance and hyperaccumulation in a new-
Zn hyperaccumulating plant specie (Sedum alfredii Hance).
Plant Soil, 258 ( n press).
Yang X E, Baligar V C, Martens D C, Clark R B. 1996. Cadmium
effects on influx and transport of mineral nutrients in plant
p cies.Plant Nut,19: 643-656.
Zhao F J, Mcgath S P, Grossland A R. 1994. Comparison of
three w t digestion methods for the determination of plant
sulphur by induc ively coupled plasma atomic emission spec-
troscopy (ICP-AES). Commun oil Sci Plant Anal, 25:407-
418.
1036 植物学报 Acta Botanica SinicaVol.45 No.9 2003
中图分类号: Q945.12 文献标识码: A 文章编号: 0577-7496(2003)09-1030-07
收稿日期:2002-1-02 接受日期:2003- 4-16
基金项目: 国家自然科学基金（20277035）；国家重大基础研究和发展规划项目（2002CB410804)。
*通讯作者。 E-mail: 。
(责任编辑: 韩亚琴)
东南景天对锌、镉复合污染的反应及其对锌、镉的吸收和积累特性
叶海波1 杨肖娥1* 何 冰1,2 龙新宪1 石伟勇1
（1.浙江大学环境与资源学院,杭州 310029； .广西大学农学院,南宁 530005）
摘要: 东南景天（Sedum alfredii Hance）已被鉴定为一种中国原生的新的锌超积累植物。 本文主要研究了锌
(Zn)、镉(Cd)复合处理水平对东南景天的生长及其对锌、镉的吸收积累特性的影响。 结果表明，在Zn/Cd复合水
平为500/100 祄ol/L时，植物生长最佳。Zn/Cd在东南景天叶片、茎部和根系中含量随着Zn/Cd处理水平的提高而
增高。在Zn/Cd 复合水平为50/400 祄ol/L时茎叶中Cd含量达最高，其中叶片Cd含量达12.1 g/kg；在Zn/Cd 复
合水平为1 000/50 祄ol/L时茎叶中Zn含量达最高, 其中茎中Zn含量达 23.2 g/kg。 植株各部位Cd含量的分布为:
叶片＞茎＞＞根系，而Zn在体内的分布为: 茎＞叶片＞＞根系。 Zn、Cd在地上部和根部的积累量也随着处理水平的
提高而增加，分别在Zn/Cd复合水平为250/400和5 0/100 祄ol/L下达高峰值。 东南景天地上部积累最高Zn和Cd
的量分别达11和5 g/plant, 其比根系的积累量分别大10和25余倍。 Zn、Cd对东南景天的生长、吸收积累的相互作
用依赖于Zn/Cd复合水平和植物部位。 在适宜Zn/Cd 处理水平范围内，Zn和Cd的吸收和积累具有相互促进作用。 高
Zn或高Cd处理均抑制了植物对Zn和Cd的吸收和积累。 本研究结果表明，东南景天不仅具有忍耐高Zn/Cd复合污染，而
且具有超量积累Zn和Cd的特异能力。 它为进一步研究植物Zn、Cd超积累的机理和Zn/Cd复合污染土壤的植物修复提
供了一种新的材料。
关键词： 复合污染; 镉; 锌; 超积累; 东南景天