GROWTH OF LEUCAENA LEUCOCEPHALA (LAM.) DE-WIT IN DIFFERENT SOIL COMPOSITIONS OF KORANGI AND LANDHI INDUSTRIAL AREAS OF KARACHI, PAKISTAN

Transcription

1 Pk. J. Bot., 41(6): , 29. GROWTH OF LEUCAENA LEUCOCEPHALA (LAM.) DE-WIT IN DIFFERENT SOIL COMPOSITIONS OF KORANGI AND LANDHI INDUSTRIAL AREAS OF KARACHI, PAKISTAN SYED ATIQ-UR-REHMAN 1 AND MUHAMMAD ZAFAR IQBAL 2 Deprtment of Botny, University of Krchi, Krchi-7527, Pkistn. Astrct The growth of Leucen leucocephl (Lm.) de-wit., were studied in soils collected from four sites viz., Khn Towel, Tnveer Grment, One Tech Ruer nd One Tech Ply Bord fctories in the vicinity of Korngi nd Lndhi industril res under nturl environmentl conditions. L. leucocephl plnts grown in 25, 5 nd 75% soils of ll of the industries demonstrted reductions in mny of the growth prmeters s compred to plnts grown in Grden soil. Principlly, 75% Khn Towel fctory soil nd 5% other fctories soils exhiited gret inhiition in most of growth chrcters thn Grden soil. Plnt cover, leves nd leflets numers, lef re, lef, totl plnt dry weights nd root/shoot rtio were noticely suppressed (p<.5) in 25, 5 nd 75% Khn Towel fctory soil thn Grden soil. Sustntil retrdtion (p<.5) in root/shoot nd lef weight rtios were recorded in 25, 5 nd 75% Tnveer Grment fctory soil. 25, 5 nd 75% One Tech Ruer nd One Tech Ply Bord fctories soils literlly diminished (p<.5) plnt cover nd lef dry weight s compred to Grden soil. Introduction Environment is composed of ir, wter, lnd, plnts nd nimls. All these constituents re interdependent on one nother nd mintin lnce in nture. Some time this lnce is lost due to vrious resons. An undesirle chnge occurs in physicl, chemicl nd iologicl chrcteristics of ir, lnd nd wter due to pollutnts. Environmentl pollution is constnt thret to iot including plnts. Krchi hs three min industril zones viz., Sindh Industril Trding Estte, Lndhi Industril Trding Estte nd Korngi industril re which emit toxic pollutnts into ir, wter nd soil (Atiq-ur-Rehmn & Iql, 27). Leucen leucocephl (Lm.) de-wit, is leguminous tree, which elongs to the fmily Mimoscee nd is cultivted round rodsides nd industril res of Krchi for ornmentl purposes (Atiq-ur-Rehmn & Iql, 27) nd economiclly n importnt plnt. It is rpidly growing tree ntive to centrl Americ, with high protein content in folige nd is used s fodder for feeding livestock. Vrious kinds of industril pollutnts of ruer fctory effluent dversely ffected on elementl ioccumultion nd metolite concentrtion in component prts of Triticum estivum vr. UP-262 plnts (Hi & Iql, 1996). Cdmium, led, chromium nd zinc tretments gretly ffected the seed germintion nd seedling growth of L. leucocephl (Iql & Atiq-ur-Rehmn, 22). Nqvi & Khttk (1995) hd reported n incresed mount of chromium, nickel, copper nd led in the wste effluents from Lndhi Industril Trding Estte. Zinc is n essentil plnt nutrient ut cn e soil contminnt t high concentrtions (Polson & Adms, 197). In soil long the sewge effluents chnnels of Mlir river (Krchi), high mount of led, copper nd zinc were detected, which influenced the composition of plnt communities in the re (Qmr-Uz-Zmn & Iql, 1994). Due to destructive nd hzrdous role of towel, grment, ruer nd ply ord industries etc., it is necessry to investigte the effects of polluted soil of industril sites on growth of L. leucocephl. E-mil s: 1 tiq_flcon7663@yhoo.com; 2 mziqlotuokpk@yhoo.com

2 3126 Mterils nd Methods S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL The experiment ws conducted in greenhouse under uniform nturl environmentl conditions t the Deprtment of Botny, University of Krchi. The rnge of mximum temperture, minimum temperture, verge temperture nd tmospheric reltive humidity during the experiment ws etween C, C, C nd 14-88%, respectively. The wether outlook ws mostly sunny with rnge of 1:3-11:41 hours sun shine. Helthy nd uniform-sized seeds of Leucen leucocephl (Lm.) de-wit, were chosen from Krchi University Cmpus. Due to hrd seed cot, the seeds were slightly cut t one end nd were sown in grden soil (lom soil) t 1 cm depth in lrge pots. The pots were irrigted dily. After out one month period, uniform-sized seedlings were trnsplnted into pots of 19.8 cm in dimeter nd 9.6 cm in depth in different soil rtios (25% fctory soil + 75% grden soil; 5% fctory soil + 5% grden soil; 75% fctory soil + 25% grden soil) of Khn Towel, Tnveer Grment, One Tech Ruer nd One Tech Ply Bord fctories. These soils were collected t -3 cm depth from Korngi nd Lndhi industril regions of Krchi. The grden soil ws used s control. The frction of grden soil ws one prt mnure nd two prts fine snd. In the preliminry studies, pure soils of ll industries hrdly showed ny response to seed germintion nd seedling growth. There were six replictes for ech tretment nd the experiment ws completely rndomized. Only one seedling ws grown in ech pot nd the plnts were irrigted dily. Every week, pots were reshuffled to void light/shde or ny other greenhouse effects. Seedlings height, numer of leves nd plnt cover were recorded fter every two weeks for ten weeks. After ten weeks, numer of leflets nd lef re of ech plnt were recorded nd ll the plnts of L. leucocephl were crefully removed from the pots nd wshed thoroughly to mesure root, shoot nd seedling length. Root, shoot nd leves were seprted for drying in n oven t 8 C for 24 hours. Oven-dried weights of root, shoot nd leves nd totl plnt dry weight were recorded. Root/Shoot rtio, lef weight rtio, specific lef re nd lef re rtio were determined s follows: Root/Shoot rtio = Lef weight rtio = Specific lef re (cm 2 g -1 ) = Lef re rtio (cm 2 g -1 ) = Root dry weight Shoot dry weight Lef dry weight Totl plnt dry weight Lef re Lef dry weight Lef re Totl plnt dry weight For soil nlysis, the smples were ir-dried, lightly crushed nd pssed through 2 mm sieve nd kept in the lortory. For mechnicl nlysis of soil, corse snd ws determined y sieve method using.5 mm sieve (Anon., 1951). Mximum wter holding cpcity (W.H.C.) ws mesured y the method of Keen (1931). Soil orgnic mtter ws determined ccording to Jckson (1958). Clcium cronte concentrtion ws determined y cid neutrliztion, s descried y Qdir et l., (1966). Bower & Wilcox (1965) methodology ws used to determine totl solule slts wheres, soil ph ws recorded y direct ph-reding meter (MP 22 ph Meter) (Mettler, Toledo). Aville sulfte in soil ws determined y turidity method s descried y Iql

3 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3127 (1988), using colorimeter (Photoelectric Colorimeter AE-11M). Soil hevy metls were lso determined. In this regrd, one grm dried soil smple ws tken in 5 ml eker nd digested with 5 ml concentrted nitric cid (HNO 3 ) + 5 ml concentrted perchloric cid (HClO 4 ), heted t 9 C for 2½ hours. Therefter, little mount of distilled wter ws dded in the digested residue nd filtered through Whtmn filter pper No. 42 the volume of filtrte ws mde up to 5 ml using distilled wter nd filtrte ws diluted 1 times for copper, zinc nd chromium nlyses y tomic sorption spectrophotometer (Perkin Elmer Model No. 31). All the dt ws sttisticlly nlyzed y ANOVA (Steel & Torrie, 1984) nd DMRT (Duncn, 1955) (p<.5) using personl computer softwre pckges Costt version 3. nd SPSS version 1.. Reduction in percentge of growth dt ws determined in treted soils of the fctories reltive to control soil s descried y Atiq-ur-Rehmn & Iql (27). Results Plnt cover nd numer of leves of Leucen leucocephl were decresed in 25, 5 nd 75% soils of ll of the industries s compred to Grden soil. Khn Towel nd One Tech Ply Bord fctories soils significntly reduced plnt height, plnt cover nd numer of leves in 25, 5 nd 75% soils. Plnt height (5.3 cm) (Fig. 1) of L. leucocephl ws gretly reduced (p<.5) in 75% Khn Towel fctory soil, wheres plnt cover (14.92 cm) (Fig. 1) nd numer of leves (8.33) (Fig. 1c) were prominently retrded (p<.5) y 25, 5 nd 75% Khn Towel fctory soil thn plnt height (6.72 cm), plnt cover (24.92 cm) nd numer of leves (16.83) of L. leucocephl in Grden soil. Plnt height (6.57 cm) (Fig. 2) ws reduced in 5% Tnveer Grment fctory soil s correlted to plnt height (6.72 cm) in Grden soil. Plnt cover (16.8 cm) (Fig. 2) ws mrkedly stunted (p<.5) y 5 nd 75% Tnveer Grment fctory soil s correlted to plnt cover (24.92 cm) in Grden soil. 75% Tnveer Grment fctory soil oviously reduced the leves numers (11.17) (Fig. 2c) comprtively to the numer of leves (16.83) in Grden soil. Plnt height (6.13 cm) (Fig. 3) of L. leucocephl ws reduced y 5% One Tech Ruer fctory soil relted to plnt height (6.72 cm) in Grden soil. Plnt cover (16.82 cm) (Fig. 3) ws significntly (p<.5) less y 25, 5 nd 75% soil, wheres numer of leves (9.67) (Fig. 3c) ws clerly reduced (p<.5) y 5% One Tech Ruer fctory soil s compred to plnt cover (24.92 cm) nd numer of leves (16.83) in Grden soil. The reduction ws notle (p<.5) in plnt height (4.53 cm) (Fig. 4) in tretment of 5 nd 75% One Tech Ply Bord fctory soil nd plnt cover (13.6 cm) (Fig. 4) (p<.5) in 25, 5% nd 75% soil s compred to plnt height (6.72 cm) nd plnt cover (24.92 cm) in Grden soil. The numer of leves were lowered y 25% One Tech Ply Bord fctory soil (9.5) (Fig. 4c) s compred to numer of leves (16.83) in Grden soil. 25, 5 nd 75% soils of Khn Towel, Tnveer Grment, One Tech Ruer nd One Tech Ply Bord fctories reduced numer of growth properties of L. leucocephl s compred to Grden soil. 25 nd 75% Khn Towel fctory soil rought out conspicuous reduction (p<.5) in root nd seedling length, wheres shoot length ws oviously stunted (p<.5) in 75% soil over Grden soil (Tle 1). Root dry weight ws mnifestly suppressed (p<.5) in 5 nd 75% soil s compred to Grden soil. Numer of leflets, lef re, lef nd totl plnt dry weights nd root shoot rtio were pprently depleted (p<.5) in 25, 5 nd 75% soil.

4 3128 Height (cm) Cover (cm ) S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL 1 1 No. of leves Figs. 1, & c: Periodicl growth of Leucen leucocephl in Khn Towel fctory soil. A = Grden soil; B = 25% fctory soil + 75% grden soil; C = 5% fctory soil + 5% grden soil; D = 75% fctory soil + 25% grden soil. Sttisticl significnce determined y nlysis of vrince. Numers followed y the sme letters in ech periodicl height, cover nd numer of leves re not significntly different (p<.5) ccording to Duncn's Multiple Rnge Test. Ι Stndrd error. 1c

5 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3129 Height (cm) Cover (cm) No. of leves Figs. 2, & c: Periodicl growth of Leucen leucocephl in Tnveer Grment fctory soil. A = Grden soil; B = 25% fctory soil + 75% grden soil; C = 5% fctory soil + 5% grden soil; D = 75% fctory soil + 25% grden soil. Sttisticl significnce determined y nlysis of vrince. Numers followed y the sme letters in ech periodicl height, cover nd numer of leves re not significntly different (p <.5) ccording to Duncn's Multiple Rnge Test. Ι Stndrd error. 2c

6 313 S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL Height (cm) Cover (cm ) No. of leves c c Figs. 3, & c: Periodicl growth of Leucen leucocephl in One Tech Ruer fctory soil. A = Grden soil; B = 25% fctory soil + 75% grden soil; C = 5% fctory soil + 5% grden soil; D = 75% fctory soil + 25% grden soil. Sttisticl significnce determined y nlysis of vrince. Numers followed y the sme letters in ech periodicl height, cover nd numer of leves re not significntly different (p<.5) ccording to Duncn's Multiple Rnge Test. Ι Stndrd error. 3c

7 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3131 Height (cm) Cover (cm ) No. of leves Figs. 4, & c: Periodicl growth of Leucen leucocephl in One Tech Ply Bord fctory soil. A = Grden soil; B = 25% fctory soil + 75% grden soil; C = 5% fctory soil + 5% grden soil; D = 75% fctory soil + 25% grden soil. Sttisticl significnce determined y nlysis of vrince. Numers followed y the sme letters in ech periodicl height, cover nd numer of leves re not significntly different (p <.5) ccording to Duncn's Multiple Rnge Test. Ι Stndrd error. 4c

8 3132 S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL

9 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3133 Root nd seedling length were prominently suppressed (p<.5) from 75% Tnveer Grment fctory soil, wheres lef dry weight ws evidently declined (p<.5) y 5 nd 75% soil (Tle 1). Root/shoot nd lef weight rtios were conspicuously lesser (p<.5) t 25, 5 nd 75% Tnveer Grment fctory soil in comprison to Grden soil. 5% One Tech Ruer fctory soil produced notle decline (p<.5) in lef re, root nd totl plnt dry weights of L. leucocephl s compred to Grden soil (Tle 1). Lef dry weight ws strikingly confined (p<.5) y 25, 5 nd 75% One Tech Ruer fctory soil, while root/shoot nd lef weight rtios were distinctly less (p<.5) in 5 nd 75% soil. In cse of One Tech Ply Bord fctory, root length, seedling length nd lef re were oviously inhiited (p<.5) y 5% soil (Tle 1). Shoot length, root nd totl plnt dry weights nd root/shoot rtio were fctully restrined (p<.5) y employ 5 nd 75% soil. 25, 5 nd 75% soil showed excessive hindrnce (p<.5) in lef dry weight. Lef weight rtio ws strikingly restricted (p<.5) in 25 nd 5% One Tech Ply Bord fctory soil compred to Grden soil. 75% Khn Towel fctory soil nd 5% other fctories soils chiefly reduced mny growth vriles of L. leucocephl s compred to Grden soil (Tle 2). Khn Towel fctory soil which cused reduction in severl growth vriles of L. leucocephl hd highest mount of totl solule slts relted to Grden soil (Tle 3). Lowest orgnic mtter nd highest ph nd elevted zinc concentrtion were found in Tnveer Grment fctory soil in reltion to Grden soil. The quntity of corse snd nd concentrtions of Clcium cronte nd chromium were dequtely mplified wheres, wter holding cpcity ws sufficiently low in One Tech Ruer fctory soil s compred to Grden soil. The rnge of ville sulfte nd copper were excessively high in One Tech Ply Bord fctory soil thn Grden soil. Discussion The growth of L. leucocephl ws conspicuously low in 75% Khn Towel fctory soil thn Grden soil which might e due to high level of totl solule slts in Khn Towel fctory soil s compred to Grden soil. Erly seedling stge of rice plnts showed tht slinity induced significnt repression in seedling growth very soon fter trnsplnting in sline solution (Shereen et l., 25). 5% Tnveer Grment fctory soil displyed pprent depletion of growth in L. leucocephl plnt y virtue of lower rte of orgnic mtter, ph nd zinc in Tnveer Grment fctory soil thn Grden soil. Singh (1986) oserved tht in those plnt communities which hd higher percentge of soil orgnic mtter, the wter holding cpcity of soil ws consequently incresed due to the colloidl nture of the orgnic mtter. The soil ph lso hs n indirect effect on plnts (Wlter, 1971). A high percentge decrese in seed germintion (27.9%) nd seedling length (38.4%) with 125 µg -ml zinc tretment ws illuminted in Peltophorum pterocrpum s compred with control (Iql & Shfiq, 1999). A lot of growth prmeters of L. leucocephl were dversely ffected in 5% One Tech Ruer fctory soil which might e due to considerle mount of corse snd, clcium cronte nd chromium nd lower wter holding cpcity in One Tech Ruer fctory soil. Gohr et l., (23) reveled tht soil texture hd mrked effect on root morphology of cotton plnts. An pprecile mount of clcium cronte ( %) is the chrcteristic fetures of rid zone soils (Auert, 196). The reduction in plnt growth nd development especilly dry mtter of Triticum estivum L. cv. UP 23 occurred due to uptke of chromium y plnts (Shrm & Shrm, 1996).

10 3134 S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL

11 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3135

12 3136 S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL

13 GROWTH OF LEUCAENA LEUCOCEPHALA IN DIFFERENT SOIL COMPOSITIONS 3137 Diverse growth perspectives of L. leucocephl ws literlly less in 5% One Tech Ply Bord fctory soil which might e cused due to high content of ville sulfte nd copper. Mhoney (1984) exposed tht ozone nd sulfur oxide significntly reduced the lef re rtio nd root shoot rtio of yellow poplr seedlings. The indices of tolernce for oth Cu nd Fe ppliction exhiited tht Alizi leeck seedlings were less tolernt, prticulrly t higher concentrtions (Iql & Rhmti, 1992). It ws found tht the soils of the industril res of Korngi nd Lndhi re noxious for plnt growth, predominntly t enhnced concentrtion of 5 nd 75%. Khn Towel fctory soil showed most detrimentl effects t different soil rtios prticulrly t high concentrtion of 75%, susequently One Tech Ply Bord fctory soil intensively influenced the growth of L. leucocephl in different soil compositions especilly t 5% soil. Atiq-ur-Rehmn (27) demonstrted tht A. leeck ws gretly ffected in 75% Khn Towel nd One Tech Ply Bord fctories soils. He hd lso noted tht Azdircht indic growth from plnts of Krchi University were prominently injurious y Khn Towel fctory soil. The pst studies exhiited tht Tnveer Grment fctory therefter Khn Towel fctory soil drsticlly ffected the growth of L. leucocephl plnts (Atiqur-Rehmn & Iql, 27). Thespesi populne nd L. leucocephl were considerly retrded y Tnveer Grment soil extrct (Atiq-ur-Rehmn & Iql, 26). They lso reported tht A. leeck nd P. juliflor which were collected from the Krchi University loction dly ffected in One Tech ruer nd One Tech Ply Bord fctories soil extrcts, respectively. Similr results were lso recorded y Atiq-ur-Rehmn & Iql (29). They reported tht One Tech Ruer fctory soil followed y Tnveer Grment fctory soil ws severely hrmful for growth of P. pterocrpum s compred to Krchi University soil. All the industril soils prticulrly Khn Towel fctory soil ws deleterious for the growth of L. leucocephl. References Anonymous Soil Survey Mnul. U.S. Deprtment of Agriculture Hnd Book No. 18 (U.S. Government Printing Office, Wshington, D.C.). Atiq-ur-Rehmn, S. 27. Effects of soil of industril res on plnts. Ph.D. Thesis, Deprtment of Botny. University of Krchi, Krchi, Pkistn. 161 pp. Atiq-ur-Rehmn, S. nd M.Z. Iql. 26. Seed germintion nd seedling growth of trees in soil extrcts from Korngi nd Lndhi industril res of Krchi, Pkistn. Journl of New Seeds, 8(4): Atiq-ur-Rehmn, S. nd M.Z. Iql. 27. Growth of Leucen leucocephl (Lm.) de-wit, in different soils of Korngi nd Lndhi industril res of Krchi, Pkistn. Pkistn Journl of Botny, 39(5): Atiq-ur-Rehmn, S. nd M.Z. Iql. 29. Peltophorum pterocrpum (DC.) Bker ex K. Heyne growth in soils of Korngi nd Lndhi industril res of Krchi, Pkistn. Journl of Bsic nd Applied Sciences, 5(1): Auert, L Arid Zones Soils; study of their formtion, chrcteristics utiliztions nd conservtions. In: The Prolem of Arid zone, UNESCO Pulictions, Pris, pp Bower, C.A. nd L.V. Wilcox Solule slts. Methods of soil nlysis (Eds.): C.A. Blck, D.D. Evns, L.E. Ensminger, J.L. White nd F.E. Clrk. Prt 2, Americn Society of Agronomy, Inc., Mdison, Wisconsin, Duncn, D.B Multiple Rnge nd Multiple F-Test. Biometrics, 11: Gohr, Z.N., R. Ahmd nd H. Gul. 23. Growth nd development of cotton roots t vrious soil textures under sline conditions. Pkistn Journl of Botny, 35:

14 3138 S. ATIQ-UR-REHMAN & M. ZAFAR IQBAL Hi, I. nd M.Z. Iql Irrigtionl impct of ruer fctory effluent on elementl ioccumultion nd metolite concentrtion in component prts of Triticum estivum vr. UP-262. Scientific Sindh, 3: Iql, M.Z Accumultion of sulfur in folige of rodside plnttion nd soil in Krchi city. Ecology, 29: 1-5. Iql, M.Z. nd K. Rhmti Tolernce of Alizi leeck to Cu nd Fe ppliction. Ekologi (CSFR). 11: Iql, M.Z. nd M. Shfiq Toxic effects of Zn on different tree seedlings. Pkistn Journl of Scientific nd Industril Reserch, 42: Iql, M.Z. nd S. Atiq-ur-Rehmn. 22. Effects of Cd, Zn, Cr nd P on seed germintion nd seedling growth of plnts. Pkistn Journl of Environmentl Sciences, 1: Jckson, M.L Soil Chemicl Anlysis. Englewood Cliffs, NJ: Prentice- Hll, pp. 48. Keen, B.A The Physicl Properties of Soil. New York: Longmn Green nd Compny, pp. 38. Mhoney, T.M Response of yellow poplr seedlings to low concentrtions of ozone, SO 2 nd NO 2. Environmentl nd Experimentl Botny, 26(1): Nqvi, R.R. nd M.I. Khttk Study of metls chromium, nickel, copper nd led in the wste effluents of Lndhi Industril Estte of Krchi. In: Astrcts 4 th Ntionl Symposium on nlyticl nd environmentl chemistry. August Deprtment of chemistry. University of Peshwr. Pkistn. Pp. 23. Polson, D.W. nd M.W. Adms Differentil response of nvy ens to zinc. l. Differentil growth nd elementl composition t excessive zinc levels. Journl of Agronomy, 62: Qdir, S.A., S.Z. Qureshi nd M.A. Ahmed A phytosociologicl survey of the Krchi University Cmpus. Vegettio, 13: Qmr-Uz-Zmn nd M.Z. Iql Vegettion pttern long the sewge effluents chnnels of Mlir river, Krchi. Turkish Journl of Botny, 18: Shrm, D.C. nd C.P. Shrm Chromium uptke nd toxicity effects on growth nd metolic ctivities in whet, Triticum estivum L. cv. UP 23. Indin Journl of Experimentl Biology, 34: Shereen, A., S. Mumtz, S. Rz, M.A. Khn nd S. Solngi. 25. Slinity effects on seedling growth nd yield components of different inred rice lines. Pkistn Journl of Botny, 37: Singh, A.P Sesonl fluctution of orgnic mtter with reltion to moisture retention chrcteristics nd vilility of wter in slt ffected soil (Indi). Act Botnic Indic, 14: Steel, R.G.D. nd J.H. Torrie Principles nd procedures of sttistics: Mc Grw Hill Book C., Inc., Singpore, Wlter, H Ecology of Tropicl nd Su Tropicl Vegettion. Oliver nd Boyd-Edinurgh, UK, 539. (Received for puliction 2 Decemer, 28)