全 文 ：　 　第 39 卷　第 3 期
2000 年　5月
中山大学学报 (自然科学版)
ACTA　SCIENTIARUM　NATURALIUM
UNIVERSITATIS　SUNYATSENI
　
Vol.39　No.3
May　2000
　
文章编号:0529-6579 (2000)03-0082-05
Pb ,Zn and Cu Tolerance and Accumulation
in Populations of Paspalum distichum

SHU Wen-sheng1 , ZHANG Zhi-quan1 , HUANG Li-nan2 ,
LAN Chong-yu1 , YE Zhi-hong3
(1.School of Life Sciences , Zhongshan University , Guangzhou 510275 , China;
2.Department of Environmental Sciences , Zhongshan University;
3.Department of Plant &Microbial Biology , University of California , Berkeley , CA94720 , USA)
Abstract:An investigation was conducted into the multi-element tolerance of the grass Paspalum distichum
growing on Fankou(FK)and Lechang(LC)Pb/Zn mine tailings at Shaoguan , Guangdong Province.Popu-
lation of the grass growing on uncontaminated pasture was used as a control.Two tailings sites contained
higher levels of Pb , Zn and Cu , as a consequence , the heavy metal contents(Pb , Zn and Cu)in the plant
tissues collected from FK and LC tailings sites were significantly higher than those of plant samples collected
from the uncontaminated pasture.Root elongation test indicated that populations of FK and LC had signifi-
cantly higher index of tolerance and ED50 to the three metals than the control population , indicating that the
populations of FK and LC have evolved to Pb , Zn and Cu tolerant ecotypes.
Keywords:heavy metal;accumulation;tolerance;Paspalum distichum
CLC number:X753　　Document code:A
The vegetation growing on tailings is subjected to a harsh environment especially the various ad-
verse edaphic factors including the elevated heavy metals , therefore , the natural colonizers of mine
wastes often had evolved metal tolerance.An economic and effective technique with potential for re-
claiming these toxic wastes is to make use of metal tolerant plant.Various tolerant species of grasses
and legumes are used for initial coverage on disturbed land
[ 1] .There has been considerable interest in
finding native tolerant species , which are able to colonize metal-enriched soils for wasteland reclama-
tion[ 2] .Ecological survey of natural colonization of plants on five Pb/Zn mine tailings in South China
indicated that Paspalum distichum was one of five dominant species of the natural vegetation of the tail-
ings , suggesting that this grass may have evolved heavy metal tolerance and therefore has some potential
use in revegetation of Pb/Zn tailings.Therefore , the objectives of the present experiments are to
study :① lead , zinc and copper tolerance in different populations of the grass , ②accumulation of Pb ,
Zn and Cu in different populations of the grass.
基金项目:国家自然科学基金资助项目 (39870145 , 39770154);广东省自然科学基金资助项目
(990259);广东省博士启动基金资助项目 (984130)
收稿日期:1999-06-23;　作者简介:束文圣 (1968 ～ ), 男 , 博士.
1　Materials and Methods
1.1　Sample Collection
Samples of P.distichum were collected from the waterlogged areas of Fankou(FK)and Lechang
(LC)lead/zinc mine tailings respectively.The control population was sampled from an uncontaminated
pasture at the campus of Zhongshan University (ZS), Guangzhou , located approximately 200 km from
LC and FK tailings.Soil or tailings samples were also collected from rhizosphere of P.distichum at the
three study sites.
1.2　Soil and plant analyses
The soil samples were air-dried and pass through a 2mm mesh sieve.They were then determined
for pH , electrical conductivity (EC), total and DTPA extractable concentrations of Pb , Zn and Cu.
The contents of Pb , Zn and Cu in plants were analyzed after being digested with HNO3.
1.3　Root elongation test
Root elongation of tillers of the grasses collected from three different sites was tested using the
method described by Wilkins[ 3] .The working concentrations of the metals were 5 , 10 , 20 , 30 and 40
mg·L-1 for Pb;2.5 , 5 , 10 , 20 and 30 mg·L-1 for Zn;0.25 , 0.50 , 1 and 2mg·L-1 for Cu.The
tillers were kept under natural 16 h/8 h cycle at temperature of (25±5)℃.The solutions were
changed every three days.The root lengths of the tillers were measured at the end of the experiment of
14 d.Culture solution containing 0.5 g·L-1 Ca(NO3)2 without metal was used as control and there
were triplicates for each treatment.Tolerant index was calculated by following equation:
Tolerant index (TI)= Mean length of the longest root in solution with metal
Mean length of the longest root in solution without metal
×100%
2　Results and Discussion
2.1　Soil analyses
The pH value of LC tailings collected from the waterlogged area was 7.38 compared with pH 5.32
of the normal soil from the pasture of Zhongshan University.The total and extractable contents of Pb ,
Zn and Cu were higher in both tailings sites than the control site(P<0.05).EC values of two tail-
ings sites were also one magnitude higher than that of the normal soil.Judging from the levels of these
metals in the tailings , it is assumed that plants growing there must be able to withstand the toxic effect
of the metals(Tab.1).
Tab.1　The pH , EC and metal contents(mean±sd , n =4 ,mg·kg-1)of FK tailings ,
LC tailings and the uncontaminated soil(ZS soil)1)
FK tailings LC tailings Uncontaminated soil
pH 7.25±0.24 a 7.38±0.61 a 5.32±0.36 b
EC/(dS·m-1) 2.13±0.18 a 2.36±0.16 a 0.56±0.09 b
Pb Total 5686±621 a 2335±1233 b 119.16±24.50 c
Extractable 219.43±47.29 a 269.49±55.94 a 6.82±1.32 b
Zn Total 3009±78 b 7607±2088 a 79.03±20.83 c
Extractable 257.93±78.26 a 325.56±135.14 a 3.79±1.07 b
Cu Total 99±6.4 b 190.89±33.47 a 2.55±0.56 c
Extractable 10.15±2.59 a 7.38±3.26 a 1.10±0.09 b
　　1)Different letters indicate a significant difference at 5% level according to LSD test
2.2　Metal contents in plants
Plant samples collected from FK and LC tailings contained significantly higher metal concentra-
83第 3 期　　　　　　　束文圣等:双穗雀稗种群对铅 、 锌和铜的积累和耐性研究
tions in their tissues than that collected from ZS pasture (Tab.2 , P<0.05).Higher metal contents
were also observed in the root than the shoot of all the plants collected from different sites , except the
Cu concentrations in P .distichum collected from FK tailings.The roots of P.distichum growing on
waterlogged area of LC tailings accumulated the highest amount of Pb and Zn.It was a common phe-
nomenon that higher metal concentrations were observed in the root than the shoot.The results also in-
dicated that there was a close relationship between the metal contents in plant tissues and those in soil.
Tab.2　The contents of Pb , Zn and Cu of three populations of Paspalum distichum
collected from Fankou , Lechang tailings and pasture at Zhongshan University1)
Shoot
FK LC Soil
Root
FK LC Soil
Pb 79.08±23.63 c 705.5±131.1 b 15.24±2.45 c 610.4±142.8 b 1899±173 a 26.08±3.14 c
Zn 116.22±30.10 c816.58±55.44 b 78.38±14.79 c 663.9±267.9 b 1864±301 a 121.54±13.90 c
Cu 32.27±14.43 a 8.79±1.83 c 13.35±3.40 bc 21.48±2.90 b 21.38±2.29 b 20.30±6.69 b
　1)mean±sd , n=4 , dry weight , mg·kg-1
Different letters indicate a significant difference at 5% level according to LSD test
2.3　Root test
2.3.1　Root elongation
It was obvious that plants collected from the uncontaminated area were more sensitive to the three
metals and thus had relatively shorter roots than those collected from contaminated areas (Fig.1).
When only Ca(NO3)2 was added into the solution , the root length of the normal(soil)population was
significantly longer than that of the two corresponding populations from FK and LC tailings.However ,
when more than 20 mg·L-1 Pb , 10 mg·L-1 Zn and 0.25 mg·L-1 were added to Ca(NO3)2 solution
respectively , the root lengths of the normal(soil)population were severely inhibited.Distinctive popu-
lation differences were found when the tillers subjected to higher concentrations of the three metals.
Fig.1　Root growth of different populations of P.distichum
at different concentrations of Pb , Zn and Cu for a period of 14 d
(n=8 , ★ LC population, ○ FK population , ◆ Normal population)
2.3.2　Index of tolerance
Table 3 lists the index of tolerance (TI)of different populations of P.distichum at various con-
centrations of Pb , Zn and Cu.In all the metal concentrations used , TIs of FK and LC populations were
significantly higher than the normal population.In general , LC population was less sensitive to Pb and
Zn than FK population , while FK population was the less sensitive to Cu.TIs of FK population in all
Cu treatments were significantly greater than those of LC population(P<0.05).It might be due to
84 中山大学学报 (自然科学版)　　　　　　　　　　　　　第 39 卷
the rather high concentration of Cu of the FK tailings(Tab.1).
Because different root growing performance in different metal concentrations , TI value was con-
centration dependent.The present study indicated that 30 mg·L-1 Pb , 10 mg·L-1 Zn and 0.25 ～
0.50 mg·L-1 Cu were suitable for measuring the metal tolerance of different populations of P .dis-
tichum (Tab.3).
Tab.3　The values of index of tolerance(TI)of different populations of Paspalum distichum
subjected to different concentrations of Pb , Zn and Cu(mg·L-1)1)
Pb
FK LC Soil
Zn
FK LC Soil
Cu
FK LC Soil
5 69.5 b 91.5 a 53.0 c 2.5 69.5 b 86.1 a 55.4 c 0.25 84.2 a 43.2 b 27.1 c
10 50.1 b 69.0 a 46.0 c 5 68.5 a 62.7 a 45.3 b 0.5 74.1 a 34.6 b 19.7 c
20 38.2 a 45.7 a 22.9 b 10 45.2 b 56.7 a 12.1 c 1.0 50.5 a 22.6 b 18.7 c
30 24.4 b 35.0 a 8.2 c 20 38.6 a 43.4 a 8.3 b 2.0 18.2 a 13.5 b 2.9 c
40 21.3 a 22.6a 2.3 b 30 37.2 a 38.1 a 2.1 b
　1)Different letters in the same metal and row indicate a significant difference at 5% level according to LSD test
2.3.3　ED50 of the three populations
The 14 d ED50 values of soil , LC and FK populations were 7.8 , 22 and 12.5 mg·L-1 for Pb;
4.2 , 17.8 and 9.5 mg·L-1 for Zn , 0.19 , 0.22 and 1.1mg·L-1 for Cu , respectively(Tab.4).The
Tab.4　The concentrations of(mg·L-1)of Pb , Zn and Cu in solutions which produced 50% of
normal root growth in Paspalum distichum compare with studies of other species
Species ED50 Growing Sites References
Pb Paspalum distichum(FK) 12.5 Fankou Pb/Zn tailings Present study
Paspalum distichum(LC) 22.0 Lechang Pb/Zn tailings Present study
Paspalum distichum(Soil) 7.8 Normal soil Present study
Phragmites australis 15.5 ～ 20 Fankou Pb/Zn tailings Ye et al., 1997[ 4]
Typha latifolia 8.4 Fankou Pb/Zn tailings Ye et al., 1997[ 4]
Zn Paspalum distichum(FK) 9.5 Fankou Pb/Zn tailings Present study
Paspalum distichum(LC) 17.8 Lechang Pb/Zn tailings Present study
Paspalum distichum(Soil) 4.2 Normal soil Present study
Phragmites australis 2.2～ 4.3 Fankou Pb/Zn tailings Ye et al., 1997[ 4]
Typha latifolia 3.3 Fankou Pb/Zn tailings Ye et al., 1997[ 4]
Cu Paspalum distichum(FK) 1.1 Fankou Pb/Zn tailings Present study
Paspalum distichum(LC) 0.22 Lechang Pb/Zn tailings Present study
Paspalum distichum(Soil) 0.19 Normal soil Present study
Festuca rubra 0.21 (Tolerant genotypes) Karataglis , 1982[ 5]
Agrostis tenuis 0.6 Cu mine Jowett , 1958[ 6]
results indicated that P.distichum collected from FK tailings had the highest tolerance to Cu while LC
population had the highest tolerance to Pb and Zn among all the tested populations.Tab.4 compares
the ED50 values with studies of other species.Although statistic analysis could not be used to compare
the difference of ED50 values of difference species , it was obvious that P .distichum was one of the
most tolerant ecotypes , because P .distichum showed more tolerant to Pb , Zn and Cu than these
known tolerant genotypes such as Agrostis tenuis , Festuca rubra and Typha latifolia (Tab.4).
The overall results reveal that FK and LC populations of P.distichum are better able to withstand
the rather high concentrations of the three metals than ZS populations of the same species , suggesting
85第 3 期　　　　　　　束文圣等:双穗雀稗种群对铅 、 锌和铜的积累和耐性研究
that the co-tolerant(multi-tolerant)ecotypes have evolved in these two populations.Because the tail-
ings often containmore than one metal at toxic level , metal co-tolerant genotypes have a higher appli-
cation value.
References:
[ 1] 　BRADSHAW A D.Reclamation of land and ecology of ecosystems [ A] .In:WILLIAM R J , GILPIN M E , ABER
J D.Restoration ecology[M] .Cambridge:Cambridge University Press , 1987.53 ～ 74.
[ 2] 　BAKER A JM , WALKER P L.Physiological responses of plants to heavy metals and the quantification of tole-
tance and toxicity[ J] .Chemical Speciation and Bioavailability , 1989 , 1(1):7～ 17.
[ 3] 　Wilkins D A.The measurement of tolerance to edaphic factors by means of root growth[ J] .New Phytologist ,
1978 , 80:623～ 633.
[ 4] 　YE Z H , BAKER A JM , WONG M H , et al.Zinc , lead and cadmium tolerance , uptake and accumulation by
Typha latifolia[ J] .New Phytologist , 1997 , 136:469 ～ 480.
[ 5] 　KARATAGLIS S S.Effect of Aerial pollution on selection and evolution in Festuca rubra[ J] .Environmental Pol-
lution(Series A), 1982 , 27:1～ 8.
[ 6] 　JOWETT D.Populations of Agrostis spp.tolerant of heavy metals[ J] .Nature(London), 1958 , 182:186～ 187.
双穗雀稗种群对铅 、 锌和铜的积累和耐性研究
束文圣 , 张志权 , 黄立南 , 蓝崇钰 , 叶志鸿
摘　要:以正常草地的双穗雀稗 (Paspalum distichum)种群作对照 , 研究了生长于广东韶关凡口和乐昌
铅锌尾矿的 2个双穗雀稗种群的重金属耐性.凡口和乐昌铅锌尾矿都含有极高浓度的总量和有效态的重
金属 (Pb , Zn 和 Cu), 与之相应 , 采自两个铅锌尾矿的植物体内的铅 、 锌和铜的含量显著高于对照点.根
伸长的耐性实验表明 , 凡口和乐昌铅锌尾矿的2 个双穗雀稗种群对 Pb , Zn 和Cu 的耐性指数和 ED50值均显
著高于对照种群 , 这两个种群已形成对 Pb , Zn 和 Cu 的多重耐性.
关键词:重金属;积累;耐性;双穗雀稗
中图分类号:X753　　文献标识码:A
86 中山大学学报 (自然科学版)　　　　　　　　　　　　　第 39 卷
中山大学生命科学学院 , 广东 广州 510275