TAP CHi KHOA HOC VA CONG NGHE Tap 48, so 2,2010 Tr. 71-78
NGHIEN CLFU ANH HU'd'NG CUA N, P LEN K H A NANG SINH TRU'O'NG VA TICH LUY ASEN CUA LOAl DU'aNG XI
Pteris vittata L.
BUI TH! KIM ANH, T R A N V A N TIJA, DANG D I N H KIM, PHAM THj H U Y t N TRANG
l . M d D A U
Tren the gidi, cdng nghe sir dung thuc vat trong xii li d nhiem (Phytoremediation) dang dugc chu y nghien ciiu va duge biet den nhu la mdt giai phap than thien mdi trudng va ehi phi thap. Tren 450 loai thyc vat cd kha nang hap thu cao kim loai da dugc cdng bd. Cac hg thuc vat chiem uru the ve loai dugc xae djnh la "Sieu hap thu" nhu Asteraceae, Brassiaceae, Caryopyaeeae, Cyperaceae, Coonuniaceae, Fabaceae,...ed the tich luy nhieu hon 100 Ian vdi sy tich tu kim loai va phi kim cua cac cay binh thudng [12, 14]. Trong sd nhirng kim loai nang (KLN) d nhiem trong dat, Asen (As) la mgt nguyen td phd bien bdi nd la tap chat trong hau het cac loai quang kim loai Cu, Pb, Zn, Sn...Trong nghien ciiu, iing dung phuong phap Phytoremediation vao xu li As trong dat, loai duong xi Pteris vittata da dugc phat hien la loai cd kha nang sieu tich liiy Asen [6]. Kha nang hap thu va tich liiy As trong md mdt each tuyet vdi ciia Pteris vittata la phat hien cua 2 nha khoa hgc ChenTongBin d Trung Qude vao nam 1997 va Lena Q.Ma d My [6, 10]. Theo dd thi P.vittata cd the phat trien binh thudng tren dat cd chiia 50 ^ 4030 mg As/kg, tham chi nd cdn ed the sdng dugc tren phan quang dudi cd chiia ham lugng As Ien den 23400 mg/kg. Ndi bat nhat la nghien ciiu co che sinh li hgc va sinh hda nhu kha nang hiit, chdng chju va khu ddc As eiia cay. Loai nay cd the hiit 10%) As tu dat trong vdng I nam ma lugng kim loai hap thu dugc chii yeu tap trung d phan tren mat dat. Ngoai ra, P.vittata cdn la cay sdng lau nam, mdt Ian trdng cho nhieu lan thu hoach [5]. Su bd sung cac chat khac nhau theo nhieu con dudng ed the lam tang kha nang xii li d nhilm bang thuc vat [3]. Trong bai bao nay, chung tdi mudn de cap tdi chat bd sung la P va N de lam tang kha nang xii Ii d nhilm As cua loai duong xi Pteris vittata.
Ca As va P deu thudc nhdm V trong bang tuan hoan cac nguyen td hda hpc. Nhd cac dac tinh hda hpe tuong ddng nhau ma chiing cd cac con dudng boat dpng trong he thdng dat va cay nhu nhau. Me-harg va nnk [3] da nhan xet rang Arsennate va Photphate dugc hip thu gidng nhau trong cung he thdng va As dugc loai bd khdi mdi trudng dit thdng qua he thdng hiit thu cua Photpho. P la chat dinh duang can thiet cho cay trong khi As la ylu td khdng cin thilt va gay dpc cho cay. P va As canh tranh vdi nhau trong sudt qua trinh hip thu cua cay. Lugng tich liiy As ludn bj kim ham bdi su hap thu P khi P dugc bd sung. Bdi vay, boat ddng sinh li cua As va P trong cay rat khac nhau [3]. Tuy nhien anh hudng cua P len sy tich luy As trong cay vin edn nhieu dieu ehua duge biet rd. Do vay, trong nghien ciiu nay chiing tdi danh gia anh hudng ciia P nhu la phan bdn Ien kha nang hiit thu As ciia Pteris vittata
Su tich liiy As cua cay khi mdi trudng dugc cung cip nhirng ngudn N hay ham Iugng N khac nhau la khac nhau. Khi dua 5 dang N khac nhau bd sung vao cac thi nghiem rdi dem danh gia su tich liiy As cua cac thi nghiem vdi cdng thuc ddi chiing khdng bd sung N [8]. Kit qua cho thiy tdng lugng As tich liiy trong sinh khdi cua cay giam din theo day sau: NH4HCO3 >
(NH4)2S04 > Co(NH2)2 > Ca(N03)2 > KNO3 > CK. Vi vay, bd sung N dudi dang NH4"' la phu hgp nhat cbo P.vittata de tang kha nang tach chiet As trong dit. Trong thi nghiem nghien ciiu anh hudng cua N len sy sinh trudng va tich liiy As eiia eay duong xi P.vittata d bao cao nay chiing tdi sti dung ngudn N bd sung dudi dang (NH4)2S04 vdi mue dich tim ra ham Iupng N phii hgp kich thich cay phat trien va tich liiy Asen.
2. VAT LIEU VA PHU^ONG PHAP 2.1. Doi tugng nghien ciru
Doi tugng nghien ciiu la loai duong xi Pteris vittata L. dugc lay ttr khu vuc d nhilm kim loai nang xung quanh cae md chi va kem tai Lang Hich, Thai Nguyen. Day la loai than cd thugc hg Pteridaceae, phan bd phd biln d Viet Nam, cac nudc chau A, Au, Phi va chau Uc. Cay thu ve dugc trdng va cham sdc trong -vudn uom de chuan bj cho thi nghiem. Dat su dung cho nghien ciiu la dit vudn cd ham Iugng As la 24,9ppm, photpho tdng sd la 435,7ppm, nita tdng sd la 640ppm va pH = 7,87.
Hinh 1. Anh minh hoa cay duang xi Pteris vittata L. su dung trong nghien ciiu
2.2. Phuong phap phan tich
- Xae djnh tdng N theo phuang phap Kjendhal, xae dinh tdng P theo phuang phap Ascorbic-antimoantartrat
- Xae djnh ham lugng Asen trong re, than va dat tren may quang phd hap thy nguyen tit (Atomic Absorption Spectrophotometer - AAS), hang Shimazu (Nhat Ban), seri: AA -6000 tai Phdng Phan tich dpc chat mdi trudng, Vien Cdng nghe mdi trudng, Vien Khoa hpc va Cdng nghe Viet Nam.
- De phan tich ham lugng As trong cay, cay duong xi dugc chia ra hai phan: Phan tren mat dat ggi chung la than (bao gdm than va la lugc) va phan dudi mat dat gpi chung la re (bao gdm gdc va re).
2.3. Bo tri thi nghiem
2.3.1. Bo tri thi nghiem nghien ciru dnh hudng ciia P len sinh truong vd tich liiy As cua cdy duang xi Pteris vittata
Chiing tdi thilt lap 6 cdng thiic thi nghiem bd sung vao dat trdng ndng dp P khac nhau dudi dang Na2H2P04 nhu sau: 0, 200, 400, 600, 800 va 1000 ppm. Lugng N, K va As dugc bd sung
vao cae thi nghiem la nhu nhau, N bd sung la 0,6 g/chau dudi dang ure, K la 0,486 g/ chau dang KCI va As la 300 ppnV chau dudi dang Na2HAs04.7H20. Moi cdng thiic dugc lap Iai 03 lin.
Cay dugc trdng trong thi nghiem la cay gieo tir bao tir, dugc lua chgn vdi chieu cao va sd la tirong ty nhau (cay cd khoang 4 hoac 5 la; chilu cao khoang 5 cm). Mdi chau thi nghiem cd 1 kg dat va thi nghiem tiln hanh trong 04 thang.
2.3.2. Bo tri thi nghiem nghien cim dnh hudng cua N len su sinh trudng vd tich lily As cua cdy duong xi Pteris vittata
6 cdng thiic bd sung vao dit trdng ndng do N khac nhau dudi dang (NH4)2S04 da dugc thiet lap nhu sau: 0, 100, 200, 300, 400, 500 ppm. Lugng P, K va As duge bd sung vao cac thi nghiem la nhu nhau, P bd sung la 1,51 g/cbau dudi dang NaH2P04, K la 0,486 g/ chau dang KCI va As la 300 ppm/ chau dudi dang Na2HAs04.7H20. Mdi cdng thiic lap Iai 03 lan. Cay dugc trdng trong thi nghiem la nhiing cay gieo tu bao tit, dugc lua chgn nhu thi nghiem vdi P. Mdi chau thi nghiem cd I kg dat va thi nghiem tien hanh trong 04 thang. Tat ea cac thi nghiem tren deu dugc trdng trong nha kinh vdi anh sang tu nhien.
3. K £ T QUA VA THAO LUAN
3.1. Nghien cuu anh huong cua P len su sinh truong va tich liiy As cua cay duong xi Pteris vittata.
^^^'
Hinh 2. Nghien cim anh hudng ciia P len sinh tru'dng va tich luy As cua P.vittata
sau 1 thang thi nghiem
Hinh 3. Nghien cim anh hudng cua P len sinh trudng va tich luy As cua P.vittata
sau 3 thang thi nghiem.
Sau 4 thang thi nghiem, chiing tdi thu hoach de danh gia sinh trudng va tich luy As cua loai duong xi Pteris vittata dudi anh hudng cua cac ndng dp P khac nhau. O cdng thiic bd sung P la 1000 ppm, cay chi sdng dugc sau 9 tuan thi nghiem edn d ndng do P bd sung tu' 0 - 800 ppm, cay van sdng va cd sy tang trudng sinh khdi. Mot sd ket qua nghien ciiu trudc day ciing cho thay, su canh tranh giiia hap thu Asen va Photpho da dugc ghi nhan trong cac loai thuc vat phd bien nhu liia, Iiia mach, rau va trong thuc vat ehdng chju Asen [1, 3, 9, 11, 13]. Ham lugng As trong re, than, la va hat cua liia deu giam khi tang ham Iugng P len qua cao. Tuy nhien, ket qua ttr nhiing nghien ciiu gan day eho rang khdng cd sy canh tranh giiia P va As trong cay d ndng dp P thap. Theo nghien cii'u ciia Chen Tongbin, khi bd sung P vdi ndng dp thich hpp vao cac chau
thi nghiem se tang cudng kha nang sinh trudng va tich luy As cua Pteris vittata len nhieu Ian [3].
Ket qua hap thu As cua P.vittata 6 cac cdng thiic bd sung P < 800 ppm dupe trinh bay theo hinh 4.
Kit qua hinh 4 tren cho thiy, khi bd sung P vdi lugng 0, 200 va 400 ppm thi lugng As tich my trong than lin lugt la 1034; 1073,9 va 1133,16 ppm edn trong re lin lugt la 286,59; 277,13 va 258,63 ppm. Phan tich tren chi ra rang, khi bd sung Iugng P khdng qua 400 ppm thi lugng As tich liiy trong than va re cd sy thay ddi nhung khdng dang ke. Ci tbi nghiem lugng P bd sung la 600 va 800 ppm, ham lugng As tich luy trong cay tang cao, tich liiy trong than tuong iing la 1478,95 va 1549,17 ppm; trong re tuong iing la 403,51 va 506,22 ppm. Su chenh lech tten cho thiy, kha nang tich liiy As cua P.vittata cd chju anh hudng tich cue cua ham lugng P bd sung. 0 ndng dp bd sung 800 ppm P, su tich liiy As trong than va re tang cao nhat Ian lugt gap 1,5 va
1,77 lan so vdi thi nghiem khdng bd sung P.
1800 ~ -£ 1600 • a 1400 •
= 1200 ^ .y 1000 S. 800 -
Ol b. 600 - - 400 - S 200
* — * — T h a n ---•- - - Re
.,.--•
D/C 200 400 600 800 H a m lu'O'ng P bo sung (ppm)
Hinh 4. Ham lugng As tich luy trong re va than Pteris vittata sau thi nghiem
Mdt trong nhiing u'u diem cua P.vittata khi xii li KLN la kha nang tich liiy mdt lugng KLN d phan tren mat dat cao hon nhieu so vdi phan re. Chi sd tich liiy sinh hgc BF (dugc tinh bang ham lugng kim loai tdng sd trong cay so vdi ham lugng kim loai tdng sd trong mdi trudng noi cay mgc) la thdng sd rat quan trgng trong danh gia kha nang tich luy kim loai nang d mdi trudng cd miic do d nhiem khac nhau. Trong bao cao nay, chung tdi dung chi sd BFt va BFr tuong iing la chi sd giira ham Iugng kim loai nang trong than va trong re so vdi ham lugng trong mdi trudng dat. Chi sd BF trong thi nghiem nay chju anh hudng rat ldn bdi ham lugng P bd sung.
Ket qua chi ra d hinh 2 cho thay, BFt va BFr dao ddng tu 3,18 - 3,48 va tir 0,79 - 0,88, tuong ling khi lugng P bd sung < 400 ppm. Ddi vdi lugng P bd sung > 400 ppm thi ty sd BFt va BFr tang len dang ke. Dac biet d thi nghiem P bd sung = 800 ppm, he sd BFt va BFr dat lan lugt la 4,77 va 1,56. He sd BFt va BFr nay da cao gap 1,5 va 1,77 lan, tuong iing khi so vdi cdng thiic khdng bd sung P. Ket qua nay cang khang djnh hon niia ve ham Iugng P bd sung tir 600 ppm - 800 ppm thi kha nang tich luy As la cao nhat.
6-1
Chi so tich luy sinh hpc
1 1 1 1 1
DC 200 400 600 800
P bo sung(ppm)
Hinh 5. Anh hudng ctia ham lugng P bo sung len he so tich luy sinh hoc ciia cay
Sau khi ket thiic thi nghiem, sinh khdi tuoi ciia cac cdng thiic khae nhau dugc can va tinh trung binh. Chiing tdi coi trgng lugng ban dau cua eac cay dugc lua chgn la gan bang nhau vi cac cay tren deu dugc trdng tir bao tir d ciing mdt thdi diem va dugc lua chgn trudc khi dat thi nghiem la ed chieu cao va sd la nhu nhau.
~ 70 1 2
£ 60 o n-
£ 50
| 4 0
ni
> 3 0 - o
;o 20
£
£ 10 c
<n 0
p 200 400 600 800 Ham lu'O'ng P bo sung (ppm)
'' •' Hinh 6. Trgng lugng tuai cua cac cay d cac cong thiic thi nghiem khac nhau
Ket qua hinh 6 cho thay, d cdng thurc thi nghiem bd sung 800 ppm P, cay duong xi cd kha nang tang trudng tdt nhat. Cai tao dat vdi viec bd sung P de tang kha nang sinh trudng va tieh luy As ciia duong xi la viec quan trgng trong nghien ciiu ve su dung thue vat de xii li d nhiem.
Trong thi nghiem nay, cd the nhan xet nhu sau: Iugng P bd sung > 400 ppm thi cay ed kha nang sinh trudng va tich luy As cao. Dac biet, hieu qua xu Ii As tdt nhat la d ndng do P bd sung 800 ppm.
3.2. Nghien cuu anh huotig cua N len su sinh truong va tich luy As ciia cay duong xi Pteris vittata
Sau 04 thang thi nghiem, ehiing tdi da thu dugc ket qua ve sy tang trudng eiing nhu hap thu As ciia Pteris vittata is cac cdng thiic bd sung N khac nhau. Khac vdi thi nghiem bd sung P, d tat ca eae ndng do N bd sung, cay van sdng dugc nhtmg sinh khdi sau thu hoach d eae ndng do N bd sung khac nhau thi khac nhau. Kit qua vl kha nang tich luy As cua P. vittata d cac ndng do N bd sung khac nhau duge trinh bay d hinh 7 sau:
1800 1600 1 1400 t 1200
^ 1000
! 800
<
o) 600 1' 400 200
0 D/c 100 200 300
H a m lifang N bo sung (ppm)
400 500
» Than - • — R e
Hinh 7. Ham lugng As tich luy trong re va than Pteris vittata sau thi nghiem
Ket qua thu dugc cho thay, lupng As tich IGy trong than tang cao nhat la 1694,31 ppm d cdng thiic bd sung 100 ppm N. Lupng As tich Itiy trong than d cac cdng thii'c bd sung 200 va 300 ppm van eao hon so vdi cdng thiic ddi chung khdng bd sung N. Tuy vay, sy tich luy As giam nhe so vdi ddi ehii'ng d ndng dp N bd sung 400 ppm nhung da giam manh d cdng thiic bd sung 500 ppm N. Lupng As tich liiy trong re ciing cao nhat d cdng thiic bd sung 100 ppm va sy tich luy giam dan theo sy tang cua lupng N bd sung.
•BFt
•BFr
1 1 1 1 1
DC 100 200 300 400 500
N bo sung (ppm)
Hinh 8. Anh huo'ng ciia ham lugng N bo sung len chi so tich luy sinh hgc cua cay
Ket qua chi ra d hinh 8 cho thay, BF tang manh ngay d ham lugng N bd sung la 100 ppm.
Chi sd BFt va BFr dao ddng bi 1,06 - 5,21 va hr 0,43 - 2,89, m'ong tmg. BFt d cdng thii'c bd sung N la 100 ppm da tang cao gap 1,73 lan so vdi ddi chiing. Chi sd nay cao ban ban khi so sanh vdi cdng thiic bd sung 200, 300 ppm N. 6 cdng tbiic bd sung 400 ppm N tbi chi sd BF giam nhe cdn d cdng thiic bd sung 500 ppm N thi chi sd nay giam manh so vdi ddi chung. Ket qua cho thiy kha nang tich luy ciia cay giam khi bd sung lugng N > 400 ppm dat.
Sinh khdi sau khi ket thuc thi nghiem eiia cac cdng thiic khac nhau dugc can va tinh trung binh. Ket qua thu dugc chi ra tren hinh 9.
Hinh 9. Trong lugng tuai cua cac cay d cac cong thiic bd sung N khac nhau
Ket qua the hien d hinh tren cho thay, cdng thiic thi nghiem bd sung 200 ppm P, cay cd kha nang tang trudng tdt nhat. Tuy nhien, d ham Iugng N bd sung la 100 ppm cay ciing tang trudng manh hon so vdi cac cdng thiic khac. Ket qua thu dugc ttr thi nghiem nay cho thay, P. vittata sinh trudng va tich luy As cao nhat khi Iugng N bd sung tir 100 ppm - 200 ppm.
4. KET LUAN
Tu ket qua thi nghiem nghien ciiu anh hudng ciia cac yeu td dinh dudng len kha nang sinh trudng va tich luy As cua duong xi Pteris vittata, chiing tdi nit ra mdt sd ket luan sau:
Ham lugng As tich luy d phan tren mat dat cua Pteris vittata ludn cao hon nhieu so vdi phan re. Day la mdt uu diem rat ldn ciia loai duong xi nay khi iing dung vao xii' li mdi trudng.
Kha nang sinh trudng va tich liiy As cua Pteris vittata chju anh hudng tich cue cila ham lugng P va N cho vao thi nghiem, khi bd sung Iupng P < 400 ppm va lupng N > 200 ppm thi ham Iupng As tich liiy trong cay cd sy thay ddi so vdi ddi chiing nhung khdng dang ke.
Sy sinh trudng va tich liiy As ciia cay duong xi P.vittata cao nhat la khi bd sung N d ndng dp tir 100 ppm - 200 ppm va P bd sung d ndng dp 800 ppm.
TAI LIEU THAM KHAO
4.
Asher C. J., Reay, P. F. - Arsenic uptake by barley seedlings, Aust J. of Plant Physiol 6 (1979)459.
Bui Thi Kim Anh, Dang Dinh Kim, Trin Van Tua, Le Diic, Nguyen Trung Kien, Dd Tuin Anh, Nguyin Thj Hoai Phuang - Kha nang chdng chiu va tich luy As cua hai loai duong xi thu hr -vimg khai thac md. Tap chi Khoa hpc va Cdng nghe 46, 6A (2008) 248-258.
Chen Tongbin, Fan Zhilian, Lei Mei, Guang Zechun & Wei Chaoyang - Effect of phosphorus on arsenic accumulation in As-hyperaccumulator Pteris vittata L. and its implication. Chinese Science Bullehn 47 (2002) 1876-1879.
Cong Tu and Lena Q. Ma - Effects of Arsenic Concentrations and Forms on Arsenic Uptake by the Hyperaccumulator Ladder Brake. Joumal of Environmental Quality 31 (2001)641-647.
5. Chen Tong Bin, Liao Xiao-Yong, Huang Ze-Chun, Lei Mei, Li Wen-xue, Mo Liang- Yu, An Zbi-Zhuang, Wei Chao-Yang, Xiao Xi-yuan and Xie Hua - Phytoremediation of Arsenic-Contaminated Soil in China.Methods in Biotechnology, Phytoremediation:
Methods and Reviews 23 (2006) 391-395.
6. Chen Tong-Bin, Chao- Yang Wei - Arsenic accumulation by two brake fern growing on an Arsenic mine and their potential in phytoremediation, Chemosphere 63 (2006)
1048-1053.
7. Dang Dinh Kim, Bui Thi Kim Anh, Tran Van Tua et al. Heavy metal pollution in soils of four mining areas in Thai Nguyen province, Vietnam and potential for phytoremediation.
Seminar on Environmental Science and Technology Issues Related to the Urban and Coastal Zone Development. Osaka, Japan, 26* to 28* of November, 2008, pp. 376-383.
8. Liao XY, Chen TB et al - Selecting appropriate forms of nitrogen fertilizer to enhance soil arsenic removal by Pteris vittata: a new approach in Phytoremediation, Int J. Phytoremediahon 9 (4) 269-280.
9. Lin H. C. - Problems of soil arsenic: a study based on soilchemical and plant-nutritional aspects. Memoirs of the College of Agriculture, National Taiwan University 11 (2) (1977) 1.
10. Ma LQ, Komar KM, Tu C, Zhang WH, Cai Y, Kennelley ED - A fem that byperaceumulates arsenic - a hardy, versatile, fast-growing plant helps to remove arsenic from contaminated soils. Nature 409 (2001): 579-579.
11. Meharg, A. A., Macnair, M. R. - An altered phosphate uptake system in arsenate-tolerant Holciis lanatiis L, New Phytol. 116 (1) (1990) 29.
12. Salt D.E. et al. - Phytoremediation: Anovel strategy for removal of toxic metals from environmental using plants. Biotechnology 13 (1995) 468-473.
13. Sharpies, J. M., Meharg, A. A., Chambers, S. M. et al. - Arsenate sensitivity in cricoid and ectomycorrhizal fungi. Environ. Toxic, and Chem. 18 (8) (1999) 1848.
14. http://en.wikipedia.org/wiki/Phvtoremediation SUMMARY
EFFECT OF N, P ON GROWTH AND ARSENIC ACCUMULATION IN FERN Pteris vittata L.
More and more attention has been paid to the research on Ph3^oremediation and hyperaccumulators. Nowaday, the people concentrate in how to enhance the abilities of plants to accumulate more contamiinants by addition of amending reagents. In this study, the pot experiments were conducted to understand the effect of N, P on Arsenic accumulation in Pteris vittata L.. Our study was undertaken to examine the effect of Phosphorus and Nitrogen on Arsenic accumulation in the As - Hyperaccumulator, as well as to verify the feasibility of Phosphorus and Nitrogen applied as fertilizer to increase the arsenic accumulation in Pteris vittata. The result showed that. Arsenic concentration in the frond is higher than that in the root of the fem. With the P added > 400 ppm and N added 100 - 200 ppm. Arsenic accumulation in the fem were increased sharply. Obviously, Nitrogen and Phosphorus is also a potential accelerator for Phytoremediation of Arsenic contaminated soil.
Bia chi: Nhgn bdi ngdy 12 thdng 8 ndm 2009 Vien Cdng nghe mdi trudng, Vien KH&CN Viet Nam.
