Directory UMM :Data Elmu:jurnal:E:Environmental Management and Health:Vol09.Issue5.1998:

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Enviro nme ntal Manage me nt and He alth

9 / 5 [1998] 1 8 8 –1 9 3 © MCB Unive rs ity Pre s s [ISSN 0956-6163]

Biochemical changes in wheat plants as af fected by

residues of dimethoate and pirimicarb

M .A. Abo-El-Seoud

Ato mic Ene rgy Autho rity, De partme nt o f Plant Re s e arc he s , Abo u-Z abal, Egypt

M . Frost

Bio lo gis c he Bunde s ans talt für Land-und Fo rs twirts c haft, Be rlin, Ge rmany

Wheat plants were grown in fi eld plots of 3×3m area. After growth period of two months, the growing plants were sprayed with dimethoate and pirimicarb at the recom-mended dose. Spraying was repeated after a further 45 days. Plant samples were taken at intervals of zero, three, six, nine, 12 and 15 days after each application. A gradual and continuous degradation of the applied pesticides had taken place in the treated wheat shoots up to the end of the experiment. However, dimethoate showed more residues and persis-tence rather than pirimicarb. The break down and metabo-lism of the applied pesticides was correlated with some biochemical changes in the sprayed plants. Sampling dates of three and six days after application were the most critical periods to affect plant metabolism. A decline was noticed in chlorophyll, sugars and carbohydrates, total proteins and RNA con-tent of wheat shoots as a function of the applied pesti-cides. Free amino acids were accumulated in the sprayed plants, meanwhile the DNA content did not show observ-able changes as a conse-quence of the applied pesti-cides treatment.

Introduction

T h e exp a n d in g u s e of p est icid es for p r ot ect -in g cr op s a ga -in st p es t s a n d d isea se a t t a ck is a n im p or t a n t p a r t of t h e m od er n a gr icu lt u r e. P es t icid es a r e in t en t ion a lly t oxic s u b st a n ces b eca u s e of t h eir u t iliza t ion p u r p oses. Re p or t s em a n a t in g fr om a r ea s in w h ich t h es e ch em i-ca ls a r e u s ed h ave sh ow n t h a t b esid es p a t h ogen s a n d p es t s, m a n y ot h er or ga n ism s h ave fa llen v ict im t o p a r t icu la r a p p lica t ion . In t h is con n ect ion , Koem a n (1979) m en t ion ed t h a t t h e m ost obv iou s sid e effect s of t h ese t oxica n t s a r e: m or e or less w h oles a le m or t a l-it y of m a n y a n im a ls a n d p la n t s p ecies, ch a n ges in t h e a bu n d a n ce of sp ecies a n d t h e d iver s it y of ecosy st em s, a n d a r ed u ct ion in t h e p r od u ct ive p ot en t ia l of n a t u r a l r es ou r ces a n d n on - t a r get sp ecies.

Ad d it ion a lly, som e r es ea r ch er s r e p or t ed t h a t t h e u t iliza t ion of p es t icid es for cr op s p r ot ect ion w a s a ccom p a n ied by t h e a p p ea r -a n ce of s om e t oxic -a n d in h ib it ion im p -a ct s on p la n t gr ow t h . T h ese effect s r a n ge fr om a s ligh t gr ow t h in h ib it ion t o a d elet er iou s m or -p h ologica l d ist u r b a n ce for a ll t h e -p la n t or p a r t icu la r or ga n s. Ca r t w r igh t (1976) a n d As h t on a n d Cr a ft s (1981) m en t ion ed t h a t p es t icid es ca u sed d elet er iou s a lt er a t ion in cell d iv is ion , cell en la r gm en t a n d t is s u e d if-fer en t ia t ion . T h ese u n d es ir a ble effect s m igh t lea d t o gr ow t h in h ib it ion s, e p in a s t y, for m a -t ive effec-t s, a lb in ism a n d a lso cou ld r ed u ce cu t icle for m a t ion a s d em on st r a t ed by Va n An d el et a l. (1976) a n d An bu d u r a l et a l. (1986). In a d d it ion , lea f ch lor os is, w h ich is follow ed by n ecr os is, a com m on r es p on s e of p la n t s, cou ld b e t r ea t ed w it h t h e p h ot os y n t h esis in h ib it in g p es t icid es (Ad h ya et a l., 1981; M oor t h y et a l., 1992).

N a t u r a lly, t h e a bove m en t ion ed m or p h ologi-ca l ch a n ges a n d h a za r d ou s im p a ct s r esu lt in g fr om p est icid e u t iliza t ion sh ou ld b e d u e t o a d ist u r a b a n ce in t h e p h y siologica l p r ocesses a n d m et a b olic p a t h w ay s in p la n t s. P r ev iou s st u d ies in d ica t ed a n in h ih it ion in t h e sy n t h e-sis of p h ot osy n t h et ic p igm en t s, a d eclin e in

ca r b oh yd r a t es a n d su ga r s con t en t a s well a s a d ist u r b a n ce in t h e m et a b olism of p r ot ein s a n d n u cleic a cid s con t en t of t h e p est icid es t r ea t ed p la n t s (Moor t h y et a l., 1992; Sh a m s E l-Din et a l., 1995; Won g a n d Ch a n ge, 1988).

T h e p r esen t wor k in ves t iga t ed t h e b ioch em ica l r esp on se of w h ea t p la n t s t o t h e a p p lica -t ion of ei-t h er d im e-t h oa -t e or p ir im ica r b.

Materials and methods

Insecticides

1 Dim eth oa te: O,O-d im et h y l S- (m et h y l-ca r b a m oy l m et h y l) p h osp h or od it h ioa t e. It w a s u sed u n d er t r a d e n a m e of Cygon 4E , a n em u lsifi a ble con cen t r a t e w it h a n a p p li-ca t ion r a t e of 480g AI/ h a

2 Pir im icab : 2- d im et h y la m in o - 5,6-d im et h y lpy r im i5,6-d in - 4-y N,N - 5,6-d im et h y l-ca r b a m a t e. It w a s u sed u n d er t r a d e n a m e of P ir im ior 50, a w et t a ble p ow d er w it h a n a p p lica t ion r a t e of 200g AI/ h a

Field experiment and pesticides application

Wh ea t seed s (T r it icu m a est iv u m L. cv. H ein es Koga II) w er e sow n in fi eld p lot s of 3 × 3m a r ea . Aft er gr ow t h p er iod of t wo m on t h s, t h e gr ow in g w h ea t p la n t s w er e t r ea t ed w it h t h e in d iv id u a l in sect icid es a t t h e a b ove m en -t ion ed r a -t es. For ea ch p es-t icid e, -t h r ee p lo-t s w er e u sed a n d d ist r ibu t ed in a com p let ely r a n d om ized d es ign . Sp r ay in g w a s r e p ea t ed on ce m or e a ft er 45 d ay s fr om t h e fi r st a p p lica -t ion . Re p r esen -t a -t ive sa m p les w er e r a n d om ly collect ed fr om t h e t r ea t ed a n d n on -t r ea t ed w h ea t p la n t s on e h ou r a ft er a p p lica t ion (zer o t im e) a n d t h en a t in t er va ls of t h r ee, six, n in e, 12 a n d 15 d ay s. T h e ob t a in ed s a m p les w er e d iv id ed in t o sh oot s a n d r oot s a n d p la ced in a d ee p fr ee zer a t 18°C u n t il a n a ly sis.

Determination of pesticide residues

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M.A. Abo -El-Se o ud and M. Fro s t

Bio c he mic al c hange s in whe at plants as affe c te d by re sidue s o f dime tho ate and pirimic arb

9 / 5 [1 9 9 8 ] 1 8 8 –1 9 3

T h en , n -h exa n e w a s a d d ed a n d t h e m ixt u r e w a s blen d ed a ga in . T h e or ga n ic p h a se w a s con cen t r a t ed u n d er va cu u m t o 2-3m l. T h e r ed u ced ext r a ct s w er e clea n ed u p over s ilica gel, eva p or a t ed t o d r y n ess a n d t h en t r a n s -fer r ed q u a n t it a t ively t o 10m l volu m et r ic fl a s k s a n d b r ou gh t t o volu m e w it h n -h exa n t o b e u s ed for GC d et er m in a t ion .

A P YE u n ica m s er ies eq u ip p ed w it h N / P d et ect or a n d py r ex gla ss colu m n p a ck ed w it h OV.17 on 80/ 100 m ech ch r om osor b w a s u s ed for d et er m in a t ion of p es t icid es r es id u e. T h e t em p er a t u r e u sed w a s 260, 250 a n d 265°C for in ject ion , colu m n a n d d et ect or r es p ect ively.

Determination of chlorophyll content

Ch lor op h y ll con t en t of w h ea t sh oot s w a s ext r a ct ed u s in g 96 p er cen t et h a n ol on 80°C a n d est im a t ed a ccor d in g t o t h e eq u a t ion s of Win t er m a n s a n d Mot s (1965).

Carbohydrates and sugars analysis

Tota l ca r boh ydr a tes wer e deter m in ed follow -in g h ydr olysis u s-in g 1 N su lph u r ic a cid -in sea led tu bes in a n electr ic oven a t 100°C for 24h . Tota l solu ble su ga r s wer e extr a cted by 85 per cen t eth a n ol u sin g soxh elt a ppa r a tu s for 6h . Tota l h ydr olyza ble ca r boh ydr a tes a n d solu ble su ga r s wer e estim a ted u sin g th e m eth od descr ibed by Du bois et a l. (1956). Redu cin g su ga r s wer e deter m in ed in th e eth a n olic extr a ct u sin g th e AOAC m eth od (1985).

Determination of total proteins and free amino acids content

Tot a l fr ee a m in o a cid s w er e es t im a t ed in t h e et h a n olic ext r a ct u sin g t h e m et h od of Dot et a l. (1981). Tot a l N a n d cr u d e p r ot ein s w er e est im a t ed u s in g t h e u su a l m icr o-Kjeld a h l m et h od (AOAC, 1985).

Determination of nucleic acids content

RNA a n d DNA wer e ext r a ct ed a ccor din g t o t h e m et h od descr ibed by Ogu r a n d Rosen (1950). Th e UV a bsor pt ion of bot h RNA a n d DNA solu t ion s w a s m ea su r ed a t 260 a n d 280n m .

Results and discussion

Pesticides residues

De gr a d a t ion b eh av iou r of b ot h d im et h oa t e a n d p ir im ica r b in t h e t r ea t ed w h ea t sh oot s is illu s t r a t ed in Ta ble I. Dim et h oa t e s h ow ed in it ia l r es id u es of 27.35 a n d 25.34 p p m a ft er t h e fi r s t a n d secon d a p p lica t ion r es p ect ively. Aft er t h r ee d ay s of a p p lica t ion , a sh a r p d eclin e occu r ed sin ce m or e t h a n 50 p er cen t of t h e a p p lied p a r en t com p ou n d w a s d e gr a d ed . F u r t h er d e gr a d a t ion occu r ed d u r in g t h e n ext sa m p lin g d a t es, h ow ever, it w a s s low er d u r in g t h e la t er p er iod s w h en com p a r ed w it h t h e

ea r lier on es. On ly 0.09p p m of t h e a p p lied in sect icid e w a s d et ect ed in w h ea t sh oot s a ft er 15 d ay s of a p p lica t ion w it h r e ga r d t o t h e fi r st sp r ay, h ow ever, it w a s u n d et ect a ble a ft er t h e sa m e t im e for t h e s econ d a p p lica t ion . Com p a r in g r a t e of d im et h oa t e b r ea k d ow n a ft er t h e im p osed a p p lica t ion s, it w a s a p p a r en t t h a t r a t e of p es t icid e d e gr a d a t ion w a s r ela t ively h igh er a ft er t h e secon d sp r ay a s com p a r ed w it h t h e fi r st on e. N a t u r a lly, t h is ob ser va t ion sh ou ld b e a t t r ibu t ed t o t h e p h y si-ologica l st a t u s a n d t h e d evelop m en t a l gr ow t h st a ge of t h e t r ea t ed p la n t s a ft er ea ch sp r ay.

On t h e ot h er h a n d , in it ia l a m ou n t s of p ir im ica r b w er e 12.86 a n d 10.86p p m a ft er t h e fi r s t a n d secon d sp r ay r esp ect ively. Met a b olic d e gr a d a t ion of p ir im ica r b d u r in g t h e exp er i-m en t cou r se exh ib it ed n ea r ly s ii-m ila r t r en d s a s t h os e ob ser ved for d im et h oa t e. F a st d e gr a -d a t ion w a s r ecor -d e-d -d u r in g t h e ea r lier sa m p lin g d a t es a n d a slow er r a t e w a s n ot iced for t h e la t er in t er va ls. On t h e ot h er h a n d , t h e ca r b a m a t e in sect icid e u n d er in vest iga t ion b eca m e u n d et ect a ble in t h e t r ea t ed w h ea t sh oot s a ft er 15 a n d 12 d ay s of a p p lica t ion w it h con cer n t o t h e fi r st a n d secon d sp r ay r esp ec-t ively. Aga in , r a ec-t e of p ir im ica r b d ecom p osi-t ion w a s com p a r a osi-t ively h igh er in osi-t h e sp r ayed w h ea t sh oot s collect ed a ft er t h e s econ d a p p lica t ion r a t h er t h a n t h os e of t h e fi r st on e.

For both dim eth oa te a n d pir im ica r b, n o r esidu es cou ld be detected in wh ea t r oots du r in g th e stu died per iods a fter a pplica tion . Th is in dica tes th a t th er e w a s n o dow n w a r d tr a n sloca tion fr om th e sh oots a n d a lso n o pen e-tr a tion fr om th e a ccu m u la ted r esidu es on soil su r fa ce to th e gr ow in g r oots h a d occu r r ed.

Com pa r in g da t es of bot h t h e st u died pest i -cides r esidu es in w h ea t sh oot s r evea led t h a t dim et h oa t e h a s h igh er con cen t r a t ion r a t h er t h a n t h ose of pir im ica r b. In a ddit ion ,

dim et h oa t e sh owed m or e per sist en ce a n d less de gr a da t ion a s it cou ld be est im a t ed in pla n t t issu es for lon ger t im e r a t h er t h a n pir im ica r b.

Resu lts of th e pr esen t wor k a r e in a gr eem en t w ith r eleva n t stu dies con du cted ea r lier. Th u s, Szeto et a l. (1985) fou n d th a t tota l r esidu es of dim eth oa te a n d pir im ica r b a pplied to a spa r a -gu s wer e decr ea sed by a bou t 90 per cen t a fter seven days of tr ea tm en t a n d th e declin e beca m e a t a slower r a te th er ea fter. Ca br a s et a l. (1991) m en tion ed r a pid de gr a da tion for pir im ica r b a pplied to lettu ce a n d it beca m e detecta ble fi ve days a fter tr ea tm en t. Xia oh on g et a l. (1992) r epor ted a r a pid declin e of

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9 / 5 [1 9 9 8 ] 1 8 8 –1 9 3

Chlorophyll content

Da t a p r esen t ed in Ta ble II d em on s t r a t e t h e im p a ct of s t u d ied p est icid es on t h e ch lor o-p h y ll con t en t of w h ea t sh oot s. Ao-p o-p lica t ion of eit h er d im et h oa t e or p ir im ica r b r es u lt ed in a d eclin e in ch lor op h y ll “a ”, ch lor op h y ll “b ” a n d con s eq u en t ly t ot a l ch lor op h y ll con t en t . H ow ever, m a gn it u d e of t h is d eclin e d e p en d ed m a in ly on t h e la p se of t im e a ft er ea ch a p p lica -t ion . In -t h is con sid er a -t ion , -t h e low es -t va lu es of ch lor op h y ll con t en t w er e r ecor d ed in sa m -p les t a k en a ft er t h r ee a n d six d ay s of t h e fi r st a n d s econ d a p p lica t ion r es p ect ively. T h a t h old s t r u e for eit h er d im et h oa t e or p ir im i-ca n b. Sa m p les collect ed a ft er n in e a n d 12 d ay s of s p r ay s h ow ed a sligh t r ecover ed in cr ea se in t h eir ch lor op h y ll con t en t r a t h er t h a n t h os e of

t h e ea r lier in t er va ls, bu t it w a s st ill sligh t ly less t h a n t h e u n t r ea t ed con t r ol. Ch lor op h y ll con t en t of t h e t r ea t ed w h ea t sh oot s h a r vest ed 15 d ay s a ft er a p p lica t ion sh ow ed m or e or less sim ila r va lu es t o t h e u n sp r ayed p la n t s. T h u s, it cou ld b e con clu d ed t h a t t h e d elet er iou s effect of t h e u s ed p est icid a l ch em ica ls on ch lor op h y ll w a s d et ect ed in t h e ea r lier sa m p lin g d a t es a n d st a r t ed t o d isa p p ea r gr a d u -a lly in t h e l-a t er p er iod s.

On t h e ot h er h a n d , d a t a exh ib it t h a t d im et h oa t e h a d m or e p r on ou n ced effect t o d eclin e t h e ch lor op h y ll con t en t of t h e sp r ayed w h ea t sh oot s a s com p a r ed w it h p ir im ica r b. In t h is r e ga r d , t h e m a gn it u d e of d eclin e a s a fu n ct ion of t h e u sed a gr och em ica l a ft er six d ay s of sp r ay w a s 28.2 a n d 19.2 p er cen t for t h e fi r s t a p p lica t ion , h ow ever, it w a s 18.2 a n d 15.9 p er cen t for t h e secon d a p p lica t ion w it h r e ga r d t o d im et h oa t e a n d p ir im ica r b r esp ec-t ively. T h e ob ser v a b le in h ib iec-t ion im p a cec-t of t h e st u d ied in sect icid es on ch lor op h y ll con -t en -t of w h ea -t sh oo-t s d u r in g -t h e fi r s-t p er iod s a ft er t r ea t m en t m igh t b e d u e t o a d ist u r b a n ce effect on t h e p igm en t ’s b iosy n t h esis.

T h e in fl u en ce of folia r a p p lica t ion of p est icid es on t h e gr een p igm en t s con t en t of t h e t r ea t ed p la n t s w a s d iscu ssed in som e p r e-v iou s st u d ies. Ha ssa n et a l. (1978) n ot iced a d eclin e in ch lor op h y ll con t en t of cot t on p la n t leaves t r ea t ed w it h som e or ga n op h osp h or u s in sect icid es. Afi fi a n d E l-Ba lla l (1982) m en t ion ed t h a t t h e in sect icid es su m it h ion a n d d u r sb a n h a d t h e ca p a cit y t o ca u se m or e r ed u ct ion in ch lor op h y ll con t en t of b r oa d b ea n s’ leaves r a t h er t h a n d im et h oa t e a n d ga r d on a . In a d d it ion , Won g a n d Ch a n g (1988) d em on st r a t ed t h a t d im et h oa t e a n d ot h er in sect icid es in h ib it ed t h e gr ow t h a n d ch lor o-p h y ll con t en t of a lga . Recen t ly, Sh a m s-E l-Din et a l. (1995) m en t ion ed a d eclin e in ch lor op h y ll con t en t of ca bb a ge p la n t s a s a fu n ct ion of som e or ga n op h osp h or u s a p p lica t ion . On t h e ot h er h a n d , a n in cr ea se in ch lor op h y ll con t en t r esu lt ed in som e p la n t s d u e t o t h e a p p lica t ion of som e p est icid es a s m en t ion ed by F a is (1988) on leaves of n ovel or ga n es a s t r ea t ed w it h p r ot h iofos, wh ile b ot h m a la t h ion a n d p r ot h io-fos d id n ot in d u ce a n y sign ifi ca n t effect on b a la d i or a n ges leaves. T h u s it cou ld b e d ed u ced t h a t t h e effect of p est icid es on p la n t ch lor op h y ll con t en t is va r ia ble a n d it d ep en d s m a in ly on t h e a p p lied su b st a n ce, t h e t r ea t ed p la n t a s well a s t h e p la n t gr ow t h st a ge a n d m et h od of p est icid e a p p lica t ion .

Carbohydrates and sugars content

E ffect s of folia r a pplica t ion of t h e in vest iga t ed in sect icides on ca r boh ydr a t es a n d su ga r s con t en t of w h ea t sh oot s a r e dem on st r a t ed in Ta ble III. Tot a l ca r boh ydr a t es wer e de plet ed in t h e spr ayed wh ea t sh oot s in r espon se t o t h e Table II

Chlo ro phyll c o nte nt (mg/ g.d.wt) o f whe at s ho o ts as affe c te d by dime tho ate and pirimic arb applic atio n

Days after First application Second application

treatment Control Dimethoate Pirimicarb Control Dimethoate Pirimicarb

Chlorophyll “a”

0 1 5 .0 8 1 6 .2 5 1 5 .3 4 1 2 .8 5 1 3 .1 1 1 2 .4 4

3 1 4 .2 6 1 2 .3 5 1 3 .1 6 1 3 .6 5 9 .4 5 1 0 .5 2

6 1 5 .3 5 1 1 .0 3 1 2 .8 1 1 2 .9 1 1 0 .6 6 1 0 .8 3

9 1 5 .2 0 1 4 .7 8 1 3 .7 7 1 2 .6 5 1 2 .5 6 1 2 .2 5

12 1 6 .0 9 1 5 .3 0 1 4 .8 3 1 2 .7 5 1 2 .9 3 1 2 .1 6

15 1 5 .9 2 1 4 .9 8 1 5 .0 8 1 2 .9 6 1 2 .8 5 1 2 .4 1

Chlorophyll “b”

0 3 .5 6 3 .2 5 3 .2 8 2 .8 8 2 .9 1 2 .8 0

3 3 .1 1 2 .8 1 2 .8 0 2 .7 9 2 .1 2 2 .3 5

6 3 .8 5 2 .7 5 2 .7 1 2 .9 1 2 .2 8 2 .4 6

9 3 .7 6 2 .9 4 2 .9 7 2 .9 7 2 .6 5 2 .5 4

12 3 .2 4 3 .1 1 3 .1 1 2 .8 0 2 .6 1 2 .4 8

15 3 .3 8 3 .0 8 3 .1 4 2 .8 8 2 .7 4 2 .6 7

Total Chlorophyll

0 1 8 .6 4 1 9 .5 3 1 8 .6 2 1 5 .7 3 1 6 .0 2 1 5 .2 4

3 1 7 .3 7 1 5 .1 6 1 5 .9 6 1 6 .4 4 1 1 .5 7 1 2 .8 7

6 1 9 .2 0 1 3 .7 8 1 5 .5 2 1 5 .8 2 1 2 .9 4 1 3 .2 9

9 1 8 .9 6 1 7 .7 2 1 6 .7 4 1 5 .6 2 1 5 .2 1 1 4 .7 9

12 1 9 .3 3 1 8 .4 1 1 7 .9 6 1 5 .5 5 1 5 .5 4 1 4 .6 4

15 1 9 .3 0 1 8 .0 6 1 8 .2 2 1 5 .8 4 1 5 .5 9 1 5 .0 8

Table I

Re s idue s o f dime tho ate and pirimic arb in whe at s ho o ts at diffe re nt days afte r applic atio n

Dimethoate Pirimicarb

First spray Second spray First spray Second spray

Days after Percent Percent of Percent Percent

treatment ppm of loss ppm of loss ppm of loss ppm of loss

0 2 7 .3 5 0 2 5 .3 4 0 1 2 .8 6 0 1 0 .8 6 0

3 1 2 .3 6 5 4 .8 1 1 0 .6 1 5 8 .1 3 5 .2 4 5 9 .2 5 4 .0 8 6 2 .4 3

6 7 .8 1 7 1 .4 4 2 .9 5 8 8 .3 6 1 .9 5 8 4 .8 4 0 .7 3 9 3 .2 8

9 2 .4 8 9 0 .9 3 0 .8 4 9 6 .6 9 0 .8 1 9 3 .7 0 0 .0 6 9 9 .4 5

12 0 .9 3 9 6 .6 0 0 .0 2 9 9 .9 2 0 .0 6 9 9 .5 3 ND –

(4)

9 / 5 [1 9 9 8 ] 1 8 8 –1 9 3

u sed pest icides u p t o 12 days a ft er a pplica t ion . However, t h e m a gn it u des of t h is declin e depen ded on h a r vest t im e a ft er spr ayin g. In t h is con sider a t ion , t h e m a xim u m r ecor ded depr essa n t in t ot a l ca r boh ydr a t es con t en t w a s n ot iced w it h sa m plin g da t e of six days a ft er a pplica t ion . T h en , it st a r t ed t o in cr ea se a ga in t o t h e n or m a l level u p t o t h e en d of t h e exper i-m en t . T h e r edu ct ion in t ot a l ca r boh ydr a t es a ft er six days of t h e spr ay w a s 12.9 a n d 8.6 per cen t a ft er t h e fi r st a pplica t ion , a n d 11.1 a n d 8.7 per cen t a ft er t h e secon d a pplica t ion w it h r e ga r d t o dim et h oa t e a n d pir im ica r b r espec-t ively. Th u s, iespec-t cou ld be con clu ded espec-t h a espec-t dim et h oa t e w a s m or e effect ive t o de pr ess t ot a l ca r boh ydr a t es con t en t r a t h er t h a n pir im ica r b.

Tot a l solu ble su ga r s a n d r ed u cin g su ga r s con t en t exh ib it t h e sa m e t r en d a n d b eh av iou r d u r in g t h e d esign ed sa m p lin g d a t es a ft er t h e im p osed p est icid es a p p lica t ion . Sa m p lin g d a t e of six d ay s a ft er sp r ay in g sh owed t h e m ost p r on ou n ced d ep let ion in solu ble a n d r ed u cin g su ga r s con t en t of wh ea t sh oot s t r ea t ed w it h t h e t est ed p est icid es. Aga in , t h e ob t a in ed d ecr ea se in su ga r s con t en t w a s m or e ob ser v -a ble u n d er t r e-a t m en t of d im et h o-a t e.

T h e n ot icea ble d ecr ea se in ca r b oh yd r ot es a n d s u ga r s con t en t of w h ea t sh oot s in r ela -t ion -t o -t h e a p p lied p es-t icid es m igh -t b e d u e -t o t h e d is t u r b in g in fl u en ce of su ch t oxica n t s on t h e en zy m es in volved in t h e m et a b olic p a t h -w ay s of t h e a b ove m en t ion ed com p on en t s. A d ecr ea s e in su ga r s a n d ca r b oh yd r a t es in t h e

p es t icid es-t r ea t ed p la n t s w a s m en t ion ed ea r lier in r eleva n t st u d ies. Gom a a et a l. (1976) r e p or t ed t h a t d im et h oa t e h a d r ed u ced t ot a l ca r b oh yd r a t es a n d it s fr a ct ion s in t h e sp r ayed p ea p la n t s. F a is (1988) d em on st r a t ed t h a t p r ot h iofos a n d m a la t h ion sign ifi ca n t ly r ed u ced t ot a l ca r b oh yd r a t es in fr u it s of n avel a n d b a la d i or a n ges. F u r t h er m or e, Sh a m s-E l-Din et a l. (1995) fou n d a d e p let ion in su ga r s a n d ca r b oh yd r a t es con t en t in t h e p es t icid es-t r ea es-t ed ca bb a ge leaves. Ma la es-t h ion in d u ced t h e m a xim u m d eclin e follow ed by p r ot h iofos a n d p ir im ip h os -m et h y l.

Free amino acids and total proteins content

F r ee a m in o a cids sh owed con sider a ble a ccu m u la tion in wh ea t sh oots u n der str ess of th e im posed pesticides (Ta ble IV). In th is con cer n , th e obta in ed in cr ea se in fr ee a m in o a cids w a s clea r ly n oticed th r ee days a fter pestcide a pplica tion a n d u p to th e en d of th e exper i-m en t. However, th e i-m a xii-m u i-m fr ee a i-m in o a cids a ccu m u la tion a s a r esu lt of th e a pplied in secti-cides w a s r ecor ded du r in g th e in ter m edia te sa m plin g da tes of six a n d n in e days, a fter th e fir st a n d secon d a pplica tion r espectively. In th is con cer n , per cen t of m a xim u m in cr ea se w a s 145.6 a n d 128.8 per cen t a fter six days of th e fir st spr ay, h owever, it w a s 173.9 a n d 157.3 per cen t a fter n in e days of th e secon d a ppliction for dim eth oa te a n d pir im ica r b r espectively. No r egu la r va r ia tion cou ld be detected between both dim eth oa te a n d pir im ica r b con cer n in g th eir ca pa city to a ccu m u la te th e fr ee a m in o a cids in th e tr ea ted wh ea t sh oots.

Sh a m s-E l-Din et al. (1995) stu died th e effect of som e or ga n oph osph or u s in secticides on fr ee a m in o a cids con ten t of cabba ge pla n ts. No a ppa r en t im pa ct cou ld be detected in va lu es of fr ee a m in o a cids con ten t a s exer ted by m a la th ion , h owever, a declin e w a s r ecor ded w ith both pir im iph os m ethyl a n d pr oth iofos. On th e oth er h a n d, fr ee a m in o a cids ten d to be a ccu m la ted in pla n ts u n der str ess of

u n favou r a ble envir on m en ta l con dition s a n d th is a ccu m u la tion cou ld be con sider ed a s a n a da ptor fa ctor for su ch con dition s (Abo-E l-Seou d et al.1990; Abo-E l-l-Seou d a n d Ha sh im , 1994). Th u s, th e obta in ed in cr ea se in fr ee a m in o a cids con ten t in th e pr esen t wor k m igh t h ave a ben eficia l effect to fa ce th e toxic a n d u n desir -a ble im p-a cts of pesticids on th e tr e-a ted pl-a n ts.

On th e oth er h a n d, tota l pr otein s con ten t of wh ea t sh oots sh owed som e depletion s a s a fu n ction of th e im posed in secticides u p to 12 days a fter a pplica tion . However, th is declin e w a s m or e pr on ou n ced w ith a n in ter va l of six days of eith er dim eth oa te or pir im ica r b a ppli-ca tion . Sa m plin g da tes of n in e a n d 12 days a fter a pplica tion exh ibited gr a du a l r ecover ed in cr ea se in tota l pr otein s con ten t of th e tr ea ted wh ea t sh oots, bu t it w a s still less th a n th a t of Table III

Carbo hydrate s and s ugars c o nte nt (mg/ g.d.wt) o f whe at s ho o ts as affe c te d by dime tho ate and pirimic arb applic atio n

Total carbohydrates

0 2 4 5 .2 6 2 4 1 .0 8 2 4 2 .2 5 2 6 8 .3 1 2 7 0 .1 8 2 7 2 .3 5

3 2 3 9 .8 5 2 1 8 .1 5 2 2 5 .1 0 2 7 0 .8 1 2 4 6 .8 3 2 5 4 .6 1

6 2 4 1 .7 6 2 1 0 .6 1 2 2 1 .0 8 2 7 2 .0 8 2 4 1 .8 7 2 4 8 .3 0

9 2 4 3 .8 7 2 2 8 .5 6 2 3 1 .8 6 2 6 9 .3 9 2 5 3 .1 6 2 5 6 .4 7

12 2 3 9 .9 6 2 3 6 .4 3 2 3 7 .3 4 2 7 4 .6 6 2 6 8 .3 8 2 6 8 .2 4

15 2 4 0 .6 2 2 3 8 .1 6 2 4 1 .1 8 2 7 1 .2 6 2 6 9 .0 8 2 7 4 .0 8

Total soluble sugars

0 2 8 .5 6 2 7 .4 1 2 8 .8 7 3 1 .4 6 3 2 .4 6 3 2 .8 5

3 3 0 .1 1 2 2 .6 5 2 5 .1 1 3 2 .6 5 2 8 .1 6 3 0 .2 6

6 2 9 .4 2 2 0 .0 8 2 3 .4 6 3 2 .4 7 2 5 .3 1 2 8 .4 5

9 2 9 .8 6 2 3 .5 1 2 6 .3 8 3 1 .9 1 2 6 .7 5 3 0 .1 1

12 3 0 .1 4 2 5 .8 1 2 8 .1 1 3 2 .0 5 2 9 .3 1 3 0 .9 4

15 3 2 .6 5 2 8 .3 6 2 8 .9 3 3 2 .7 5 3 1 .8 6 3 2 .8 6

Reducing sugars

0 9 .6 1 8 .3 5 8 .9 2 1 1 .2 2 1 1 .3 3 1 2 .5 6

3 8 .5 3 6 .1 1 6 .2 4 1 2 .3 8 9 .2 5 1 0 .1 1

6 9 .1 6 5 .2 2 6 .1 8 1 2 .2 5 8 .1 6 8 .9 2

9 9 .4 3 7 .3 1 6 .9 3 1 1 .6 1 1 0 .3 1 9 .3 5

12 9 .1 1 8 .9 6 7 .2 5 1 2 .4 1 1 2 .4 6 1 1 .8 6

(5)

9 / 5 [1 9 9 8 ] 1 8 8 –1 9 3

th e u n tr ea ted pla n ts. After 15 days of th e pesticida l ch em ica ls a pplica tion , n o obser va ble va r ia tion cou ld be r ecor ded between both th e spr ayed a n d n on -spr ayed wh ea t sh oots r ega r d-in g th eir pr oted-in con ten t. Com pa r d-in g th e effec-tiven ess of th e a pplied pesticides to a ffect pr o-tein con ten t of th e tr ea ted pla n t, it cou ld be in fer r ed th a t dim eth oa te h a s m or e ca picity to decr ea se pr otein con ten t r a th er th a n pir im i-ca r b. For in sta n ce, th e m a gn itu de of declin e r ecor ded w ith th e sa m plin g da te of six days

a fter th e fir st a pplica tion w a s 13.9 a n d 7.4 per cen t, m ea n wh ile it w a s 12.6 a n d 8.93 per cen t a fter th e sa m e in ter va l of th e secon d a pplica -tion for dim eth oa te a n d pir im ica r b r espec-tively. Th e pr esen t depr ession in tota l pr otein con ten t coin cides w ith th e fin din gs of Gom a a et a l. (1976) on pea pla n ts tr ea ted w ith

dim eth oa te. Sim ila r ly, Rozek a n d Ma r ecr ek (1981) r epor ted th a t dim eth oa te a n d m a la th ion declin ed lea f pr otein con ten t of pea pla n ts. In a r ecen t investiga tion Sh a m s-E l-Din et a l. (1995) stu died th e effect of con sequ en t a pplica tion s of pesticides on pr otein con ten t of th e tr ea ted ca bba ge leaves. Tota l pr otein con ten t sh owed a n in cr ea se a fter th e fir st a pplica tion in r espon se to both m a la th ion a n d pr oth iofos. However, a ll th e u sed pesticides decr ea sed pr otein con ten t of th e tr ea ted ca bba ge leaves a fter th e secon d a n d th ir d a pplica tion .

Nucleic acids content

RNA a n d DNA con ten t of wh ea t sh oots a s a ffected by dim eth oa te a n d pir im ica r b spr ay-in g is pr esen ted ay-in Ta ble V. RNA con ten t w a s decr ea sed du r in g th e in ter m edia te sa m plin g da tes du e to th e u tiliza tion of th e stu died pesti-cides. Aga in , a sa m plin g da te of six days a fter spr ay w a s th e m ost cr itica l per iod to r edu ce RNA con ten t of th e tr ea ted pla n ts. Th e in h ibi-tion im pa ct of th e a pplied a gr och em ica l on RNA con ten t of tr ea ted pla n ts sta r ted to disa p-pea r fr om sa m plin g da te of n in e days a n d u p to th e en d of th e exper im en t. On th e oth er h a n d, n o detecta ble va r ia tion s cou ld be in du ced in th e DNA con ten t of wh ea t sh oots a s fa r a s th e in flu en ce of th e spr ayed in secticides w a s con -sider ed. On ly a sim ple flu ctu a tion cou ld be obser ved. In oth er wor ds, DNA con ten t exh ib-ited fixed ph en om en on tow a r d th e u sed in secti-cides. RNA/ DNA r a tio sh owed a ligh t decr ea se du r in g th e in ter m edia te in ter va ls a fter a ppli-ca tion du e to th e depr ession in th e RNA level. Liter a tu r e sh owed th a t ver y lim ited wor k w a s con du cted r ega r din g th e im pa ct of pesticides’ folia r a pplica tion on n u cleic a cids. Per epe-len ko (1987) sh owed th a t dim eth oa te a ffected n u cleic m eta bolism in cotton seedlin gs via th e ch a n ge in ch r om osom e a ber r a tion fr equ en cy.

As a gen er a l con clu sion , it cou ld be m en tion ed th a t th e a pplied in secticides wer e gr a du a lly declin ed a n d decom posed du r in g th e design ed sa m plin g da tes a fter a pplica tion . Th e de gr a da tion of th e spr ayed in secticides w a s a ccom pa n ied by som e bioch em ica l ch a n ges in th e tr ea ted wh ea t sh oots. Sa m plin g da tes of th r ee a n d six days a fter a pplica tion wer e th e m ost cr itica l per iods to in du ce som e distu r ba n ces in th e pla n t m eta bolism . Th e la ter sa m plin g da tes sh owed r e gu la r ch a n ge of th e deter m in ed ch em ica l con stitu en ts to th e n or m a l levels. Th u s, it cou ld be con clu ded th a t th e im pa ct of th e u sed pesticides on th e Table IV

To tal pro te ins and fre e amino ac ids c o nte nt (mg/ g.d.wt) o f whe at s ho o ts as affe c te d by dime tho ate and pirimic arb applic atio n

Free amino acids

0 2 .3 5 2 .8 1 2 .7 4 2 .0 8 2 .1 3 2 .2 7

3 2 .2 6 3 .1 1 4 .3 4 2 .3 1 4 .0 4 3 .8 1

6 2 .1 5 5 .2 8 4 .9 2 2 .2 6 5 .1 1 5 .2 3

9 2 .4 7 4 .9 7 4 .0 1 2 .1 8 5 .9 7 5 .6 1

12 2 .5 1 5 .2 5 3 .9 1 2 .2 7 4 .2 2 5 .2 1

15 2 .3 1 3 .1 6 4 .8 1 2 .3 6 4 .2 7 3 .1 4

Total proteins

0 1 6 7 .3 1 1 7 0 .3 1 1 6 9 .4 5 1 4 5 .3 1 1 4 7 .2 6 1 4 5 .1 6

3 1 7 1 .3 5 1 5 3 .2 6 1 5 8 .1 1 1 4 2 .2 8 1 3 2 .8 3 1 4 0 .1 1

6 1 6 9 .6 5 1 4 6 .1 1 1 5 0 .3 1 1 5 6 .1 1 1 2 7 .1 6 1 3 3 .0 6

9 1 7 2 .3 1 1 4 8 .3 9 1 5 7 .1 1 1 4 6 .4 3 1 3 1 .2 4 1 3 9 .3 1

12 1 7 0 .3 1 1 5 6 .2 1 1 6 3 .2 2 1 4 4 .2 6 1 4 0 .3 5 1 4 3 .1 9

15 1 7 0 .9 8 1 6 8 .4 5 1 7 0 .1 4 1 4 5 .1 5 1 4 6 .8 1 1 4 7 .1 5

Table V

Nuc le ic ac ids c o nte nt (mg/ g.d.wt) o f whe at s ho o ts as affe c te d by dime tho ate and pirimic arb applic atio n

RNA

0 1 6 .2 5 1 7 .0 9 1 7 .4 3 1 7 .8 2 1 7 .3 3 1 7 .1 1

3 1 6 .1 8 1 5 .2 2 1 4 .1 1 1 6 .3 1 1 3 .1 8 1 4 .1 2

6 1 7 .3 1 1 2 .2 6 1 1 .2 8 1 6 .2 8 1 1 .0 6 1 2 .2 5

9 1 6 .9 2 1 4 .3 1 1 4 .8 6 1 7 .1 5 1 4 .1 8 1 5 .2 6

12 1 7 .3 1 1 4 .2 5 1 5 .2 6 1 6 .9 3 1 5 .3 7 1 5 .9 2

15 1 7 .2 8 1 5 .6 9 1 7 .0 8 1 6 .2 6 1 6 .9 3 1 7 .2 3

DNA

0 2 .8 2 2 .8 5 2 .9 1 2 .7 1 2 .8 1 2 .7 2

3 2 .7 6 2 .7 4 2 .7 6 2 .7 0 2 .7 6 2 .5 1

6 2 .6 1 2 .6 6 2 .7 2 2 .6 8 2 .6 8 2 .4 2

9 2 .7 2 2 .7 5 2 .7 4 2 .7 5 2 .5 2 2 .6 1

12 2 .8 5 2 .8 1 2 .8 6 2 .6 9 2 .6 3 2 .6 5

15 2 .6 5 2 .8 3 2 .7 2 2 .7 2 2 .8 6 2 .7 3

RNA/ DNA ratio

0 5 .7 6 5 .9 9 5 .9 9 6 .5 8 6 .1 7 6 .2 9

3 5 .8 6 5 .5 5 5 .1 1 6 .0 4 4 .7 8 5 .6 3

6 6 .6 3 4 .6 1 4 .1 5 6 .0 7 4 .1 3 5 .0 6

9 6 .2 2 5 .2 0 5 .4 2 6 .2 4 5 .6 3 5 .8 5

12 6 .0 7 5 .0 7 5 .3 3 6 .2 9 5 .8 7 6 .0 1

(6)

9 / 5 [1 9 9 8 ] 1 8 8 –1 9 3

m eta bolic ch a n ges is a tem por a r y effect a n d it h a d n ea r ly disa ppea r ed a t th e en d of th e exper ipm en t. Th e obta in ed bioch em ica l ch a n ges du r in g th e in ter m edia te sa m plin g da tes m igh t be du e to th e toxic a n d in h ibitor y in fl u en ce of th e pesticides’ r esidu es on th e en zym a tic system s in volved in th e m eta bolic pa th w ays of th e stu died con stitu en ts.

References

Ab o-E l-Seou d , M.A. a n d H a s h im , M .F. (1994), “P h y siologica l a n d b ioch em ica l effect s of folia r k in et in a p p lica t ion on s h oot s of w a t er st r essed cor n ”, Z a ga z ig J ou r n a l of A g r icu

l-tu re R esea rch , E gy p t , Vol. 21, p p. 367-77.

Abo-E l-Seou d, M.A., Ha m m a m , M.A., Sa k r, A.A. a n d Der a z, S.A. (1990), “Bioch em ica l a spects of ga m m a r a dia tion , k in etin a n d L-pr olin e a ppli-ca tion in du cin g dr ou gh t toler a n ce for w a ter str essed cotton leaves”, Z a ga z ig J ou r n a l of

A gricu ltu ra l R esea rch, E gypt, Vol. 17, pp. 623-36.

Ad h ya , T.K., Su d h a k a r, B. a n d Set h u n a t h a n , N. (1981), “St a b ilit y of com m er cia l for m u la t ion s of fen it r ot h ion , m et h y l p a r a t h ion in a n a er o-b ic soil”, J ou r n a l of A g r icu ltu re a n d Food

Ch em istr y, Vol. 29, p p. 90-3.

Afifi, F.A. a n d E l-Ba lla l, S.A. (1982), “P h ysiologica l h om osta tis of ph otosyn th etic pigm en ts in br oa d bea n (Vicia fa ba l.L) u n der str ess of or ga n oph osph or u s pesticides”, Egyptia n J ou r

-n a l of Ph ysiologica l S cie-n ces, Vol. 9, pp. 101-2.

An bu d u r a i, P.R., Ma n n a r, M .R. a n d Bos e, S. (1986), “E ffect s of m et h y l p a r a t h ion on b et a cya n in effla x fr om b eet r oot d is cs”, B u lletin of E n v

i-r on m en ta l Con ta m in a tion T ox icolog y, Vol. 37,

p p. 448-52.

AOAC (1985), Officia l M eth od s of A n a lysis of A

sso-cia tion of Offisso-cia l A n a lytica l Ch em ists, 12t h

ed ., Wa sh in gt on , DC.

Ash t on , F.M. a n d Cr a ft s, L.S. (1981), M od e of

A ction of H er b icid es, 2n d ed ., Wiley In t er

-scien ce P u blica t ion , p p. 15-18.

Ca b r a s, P., Sp a n ed d a , L., Ca b it za , F., Cu b ed d u , M ., Ma r t in i, M.G. a n d Br a n d olin i, V. (1991), “P ir -im ica r b a n d it s m et a b olit e r es id u es in let t u ce. In fl u en ce of cu lt u r a l en v ir on m en t ”, J ou r n a l

of A g r icu ltu re a n d Food Ch em istr y, Vol. 38,

p p. 879-82.

Ca r tw r igh t, P.M. (1976), “Gen er a l gr ow th r espon ses of pla n ts”, in Au du s, L.J . (E d.), Her b icid es, Aca dem ic P r ess, N ew Yor k , N Y, pp. 55-7. Dot , E ., Sh ib ot a , D. a n d Ma t a b a , T. (1981),

“Mod ifi ed color im et r ic n in h yd r in m et h od for p e p t id a se a ssay ”, A n a lytica l B ioch em istr y, Vol. 118, p p. 173-84.

Du b ois, M ., Gilles, K.A., H a m ilt on , J .K., Reb er s, P.A. a n d Sm it h , F. (1956), “Color im et r ic m et h od for d et er m in a t ion of s u ga r s a n d r ela t ed su b st a n ces”, A n a lytica l Ch em istr y, Vol. 28, p p. 350-6.

F a is, G.N. (1988), S om e S id e E ffect of Pesticid es on

Cir tu s, P h D T h esis, F a cu lt y of Agr icu lt u r e,

Za ga zig Un iver sit y, E gy p t .

F r ost , M. a n d Ab o-E l-Seou d , M.A. (1997), “T r a n slo-ca t ion , fa t e a n d p er sist en ce of 14_{C-p ir im ica r b}

in wh ea t p la n t s a n d soil”, A rch iv es of Ph

y-top a th olog y a n d Pla n t Protection (in p r ess).

Gom a a , E .A., He ga zi, S.M. a n d Ash ou r, M.B. (1976), “E ffect of d im et h oa t e on y ield a n d ch em ica l com p osit ion of b ea n s”, Z a ga z ig J ou r n a l of

A gr icu ltu re R esea rch , Vol. 3, p p. 117-19.

H a ss a n , H .H ., H iga zy, M.A., E l-Sh ir fi e, Y.H . a n d Kh eir, N.E . (1978), P r oc Sy m p “Agr icu lt u r e a n d H ea lt h ” E SE S, p p. 25-40.

Koem a n , J.H. (1979), “Ch em ica ls in th e envir on -m en t a n d th eir effects on ecosyste-m s”, in Geiss-bü h ler, H. (E d.), A dva n ces in Pesticid e S cien ce, Per ga m on P r ess, New Yor k , NY, pp. 25-38. M oor t h y, P., Gop in a n d h a n , T.N., Sa n t h a n a m , R.,

Ba la k u m a r, T. a n d An bu d u r a i, P.R. (1992), “P h y t ot oxicit y of m et h y l p a r a t h ion w it h s p ecia l r efer en ce t o p h ot osy n t h es is in w h ea t s eed lin gs ”, B u lletin of E n v ir on m en ta l Con ta m

-in a tion T ox icolog y, Vol. 48, p p. 138-43.

Ogu r, N. a n d Rosen , G. (1950), “Se p a r a t ion of p la n t p en t os e n u cleic a cid s”, A rch iv es of B ioch em

-istr y, Vol. 25, p p. 262-76.

P er e p elen k o, S.D. (1987), “E ffect of t h e d efolia n t Al’ fa -3_{a n d t h e in s ect icid e Bl- 58 on t h e}

n u cleic a cid con cen t r a t ion a n d ch r om osom e a b er r a t ion fr eq u en cy of r oot cells of cot t on ”, Vliya n ie m u t a gen ov sr edy n a

s el’s k ok h ozya ist ven n ye r a s t en iya , p p. 25-31. Rozek , S. a n d Ma r eczek , A. (1981), “E ffect of som e

or ga n op h osp h or u s in sect icid es on t h e q u a n t i-t a i-t ive a n d q u a lii-t a i-t ive ch a n ges in p r oi-t ein a n d on t h e a ct iv it y of p r ot eoly t ic en zy m es in b ea n s ”, H u gon a k ot t a t a ja W. Kr a k ow ie, Ogr od n ict wo, Vol. 8, p p. 65-78.

Sh a m s-E l- Din , A.M., Ab o- E l- Seou d , M.A., Da n ia l, L.N. a n d Ah m ed , S.M. (1995), “Bioch em ica l im p a ct s of som e or ga n op h osp h r u s in sect i-cid es on ca bb a ge p la n t s”, J ou r n a l of Pla n t

Disea ses a n d Protection, Vol. 102, p p. 655-62.

St ein w a n d t er, H . (1985), “Un iver s a l 5-m in . On lin e m et h od for ext r a ct in g a n d isola t in g p es t icid e r es id u es a n d in d u st r ia l ch em ica ls”, F r esen iu s Z An a ly t ica l Ch em ist r y, Vol. 322, p p. 752-4. Szet o, S.Y., Ver n on , R.S. a n d Br ow n , M.J . (1985),

“De gr a d a t ion of d im et h oa t e a n d p ir im ica r b in a sp a r a gu s ”, J ou r n a l of A g r icu ltu re a n d

Food Ch em istr y, Vol. 33, p p. 763-7.

Va n An d el, O.M., Va n d er Zw ee p, W. a n d Gor t er, C.J . (1976), “Mor p h ogen et ic r esp on ses of p la n t s ”, in Au d u s, L.J . (E d .), H er b icid es, Aca d -em ic P r ess, N ew Yor k , N Y, p p. 127-9.

Win t er m a n s, J .F. a n d Mot s, A. (1965), “Sp ect r op h o-t om eo-t r ic ch a r a co-t er is o-t ics of ch lor op h y lls a a n d b a n d t h eir p h eop h y t in s in et h a n ol”, B ioch em

-ica l B iop h ys-ica l A cta , Vol. 109, p p. 448-53.

Won g, P.K. a n d Ch a n g, L. (1988), “Th e effects of 2,4-D h er bicide a n d or ga n oph osph or u s in secticides on gr ow th , ph otosyn th esis a n d ch lor oph yll a syn th esis of ch la m ydom on a s r eih a r dtii (m t+)”,

En viron m en ta l Pollu tion, Vol. 55, pp. 179-89.

Xia oh on g, Z., Da d i, Z. a n d J ia n p in g, Z. (1992), “Res id u e d e gr a d a t ion of fen va ler a t e a n d d im et h oa t e on w h ea t , Br ssica ch in en s is a n d p ea ch ”, J ou r n a l of S h a n gh a i A g r icu ltu ra l