PHYSIOLOGICAL RESPONSES TO DEFICIT IRRIGATION OF YOUNG OLIVE TREES (Ole europe, L.) GROWN IN SEMI ARID AREA OF MOROCCO. Sikoui, L., A. Bouizgren, M. Krrou, H. Boull, B. Boulouh, M. Krm, V. Nngi, nd T. Oweis. 2014. Effect of three irrigtion regimes on physiologicl prmeters of new olive orchrd under semi-rid conditions of Morocco. 7 th Interntionl Conf. on Wter Resources in the Mediterrnen Bsin, Oct 10-12, Mrrkech, Morocco Adelziz BOUIZGAREN 1*, Lhssne SIKAOUI 1, Hkim BOULAL 2, Aderrouf EL ANTARI 1, Mohmmed KARROU 2, Viny NANGIA 3 nd Thei OWEIS 3 1 Unit of Plnt Breeding, Ntionl Institute for Agronomic Reserch (INRA), PO. Box 533, Gueliz 40000, Mrrkesh, Morocco. 2 Interntionl Center of Agriculturl Reserch in Dry Are (ICARDA) 3 Interntionl Center of Agriculturl Reserch in Dry Are (ICARDA), Ammn, Jordn * Corresponding uthor, Emil: ouizgren_delziz@yhoo.fr Astrct The scrcity of irrigtion is the mjor constrint fcing the olive production in Morocco. Under such conditions, deficit irrigtion is one of the techniques leding to mximizing olive yields per unit of irrigtion wter. This work ws conducted to investigte physiologicl responses, to deficit irrigtion, of young olive trees (Ole europe L.) cultivted under semi-rid conditions of Morocco. The experiment ws crried out t the Experiment Sttion of INRA Mrrkech. Three wtering regimes were studied: FDI= Full drip irrigtion (100% of ETc), DDI= Deficit drip irrigtion (70% of ETc) nd FU= Flood irrigtion (frmer s conventionl technique). The physiologicl prmeters, lef reltive wter content (LRWC), Lef chlorophyll content (LCC), totl lef minerl content (TLMC), lef protein content (LProtC), lef solule sugr content (LSSC), lef proline content (LProlC) nd stomtl conductnce were mesured t three phenologicl stges: Flowering, fruiting nd fruit set. The results showed tht t the three phenologicl stges, the low vlues of LRWC, LCC, TLMC nd stomtl conductnce were recorded under FU regime. The High vlues of LProlC, LSSC, LProtC were otined in recorded y Fun regime, suggesting tht the young trees re more exposed to wter stress under this irrigtion technique despite the high mount of pplied wter. For most of those physiologicl prmeters no significnt differences were noted etween FDI nd DDI regimes. These ltter regimes llowed, respectively, 30% nd 80% of wter sving compred to FU regime. Key words: young olive trees, deficit irrigtion, physiologicl prmeters Introduction The scrcity of wter resources in Morocco is of growing concern for the griculture sector, prticulrly in semi-rid res, ecuse of the incresing popultion, high drought frequency nd severity due to the effects of climte chnge. Moreover, these res re chrcterized y high evportive demnd (out 1500 mm/ yer), nd low nd irregulr rinfll (200-300 mm/yer). In this semi rid re, the new olive orchrds re plnted under irrigtion to ensure of the supply of wter required for growth nd development of the crop. However, lrge newly plnted re is irrigted y trditionl inefficient surfce irrigtion system which leds to high wter losses. Under conditions of wter scrcity nd drought, deficit irrigtion t selected phenologicl phses cn led to sving wter nd mximizing yields per unit of wter for given crop (Tognetti et l. 2006) without significnt yield losses. Therefore, to understnd how young olive trees respond to wter restrictions nd drought, on study
ws conducted on the physiologicl responses of this crop to deficit irrigtion under semi rid conditions of Morocco. Mteril nd methods The experiment ws conducted in three yers old olive orchrd (Ole europe L. cv Menr) instlled in 2010 t Sâd Experiment sttion of INRA, Morocco, locted 9 km from Mrrkech city (32 N, 8 08 W, 411 m ltitude). The climte is typicl Mediterrnen. Spring nd summer sesons t the experimentl site re normlly chrcterized y severe drought stress ssocited with high tempertures (Tle 1). The soil hs lomy cly texture nd it is over 2 m deep. Tle 1: Men climtic vriles in the experimentl yer. Climtic vrile 2013 Rinfll Septemer Mrch (mm) 164.2 Rinfll April August June (mm) 26.8 Men dily min temp Jnury Ferury ( C) 11.5 Men dily mx temp July August ( C) 45.5 Totl rinfll 12 months (mm) 191.0 Totl 12 months ET 0 (mm) 1508 Three wtering regimes were studied: FDI= Full drip irrigtion (100% x ETc), DDI= Deficit drip irrigtion (70% x ETc), nd FU=Flood irrigtion (frmer s prctice). For drip irrigtion tretments (FDI nd DDI), the frequency of irrigtion ws two dys; while it ws round one month in the cse of flood irrigtion during summer. The full drip irrigtion regime received the crop wter requirement (ETc). The ETc ws clculted using the eqution: ETc = ETo x Kc x Kr /Ne Where ETo is the reference evpotrnspirtion, Kc is the crop coefficient for olive tree, Kr is the coefficient to correct for incomplete soil cover nd Ne is the efficiency of irrigtion network. ET 0 ws estimted using Penmn-Monteith eqution nd dily meteorologicl dt collected from n utomtic wether sttion locted 50 m wy from the experiment plot. The Kc vlues used re the ones reported y Orgz nd Fereres (1997); while the vlue of Kr ws estimted t 0.8 (Fereres nd Golhmer, 1990). The mounts of irrigtion pplied for the three wtering regimes FDI, DDI nd FU were 116 mm, 81.2 mm nd 538 mm, respectively. A rndomized complete-lock design ws used with three replictions of 21 trees ech. The spcing etween trees ws 8 m x 8 m. The physiologicl prmeters were mesured t flowering, fruit set nd fruiting stges: Lef reltive wter content (LRWC): LRWC ws defined s follows (Mkel et l., 1998): LRWC(%)=((FW-DW)/(TW-DW)) x100. Where FW (fresh weight), TW (turgid weight) nd DW (dry weight). Lef proline content (LProlC): is determined using the method descried y Btes et l. (1973). Lef totl Chlorophyll contents (LTCC): Chlorophyll concentrtion ws mesured y the method descried y Arnon (1949).
LRWC (%) Lef protein content (LprotC): LProtC ws determined using the method descried y Brdford (1976). Lef solule sugr content (LSSC): The content of solule sugrs ws determined ccording to the method of Duois et l. (1956). Stomtl conductnce: Stomtl conductnce to H 2 O (g mm s -1 ) were mesured in leves, using lef porometer (model sc-1). Sttisticl nlysis Dt were sttisticlly nlyzed using the nlysis of vrince nd men comprisons were crried out using the Student-Newmn-Keuls test when significnt tretment effects occurred. Results Lef reltive wter content (LRWC): A significnt vrition ws shown mong the three studied irrigtion regimes t flowering, fruiting, nd fruit set stges (Figure 1). The high vlues of this prmeter were otined under FDI; ut the difference with DDI ws not sttisticlly significnt. The lowest vlues of LRWC were otined under FU regime. 90 80 70 60 50 40 30 20 10 0 FDI DDI FU FDI DDI FU FDI DDI FU Flowering Fruit set Fruiting Irrigtion regimes X phenologicl stges Figure 1: LRWC of young olive trees under three irrigtion regimes for the three phenologicl stges (Vlues with the sme letter do not differ significntly (P> 0.05)) Lef proline content (LProlC): At the three phenologicl stges, the ccumultion of proline in leves vried significntly etween the three irrigtion regimes (Tle 2). The FU regime induced high vlues of LPC which reched 21.1, 23.6 nd 31.1 mg. g FW -1 t flowering, fruit set nd fruiting stges respectively. The FDI nd DDI regimes did not differ significntly. Lef chlorophyll content (LTCC): The vrition of the irrigtion regimes induced significnt effect on LTCC of young olive trees (Tle 2). The high vlues of this prmeter were otined under FDI regime with 22.7, 15.1 nd 23.3 mg. ml -1 t flowering, fruit set nd fruiting stges, respectively tht did not differ significntly with those otined under DDI regime. Lef Proteins content (LProtC): Wter regime ffected significntly the LProtC of young olive trees t fruit set nd fruiting stges (Tle 2). The high ccumultion of proteins in young olive leves ws noted under FU regime with 14.9, 23.3, nd 54.3 mg. mg FW -1 t flowering, fruit set nd fruiting stges, respectively.
Stomtl conductnce (Mmol H 2 O m-² S -1 ) Solule sugr (LSSC): A significnt vrition ws shown mong the irrigtion regimes for the LSSC t the three phenologicl stges (tle 2). Within the sme phenologicl stge, the low nd high vlues were chieved under FDI nd FU regimes, respectively. At fruiting stge, the LSSC vried etween 289.2 nd 350.1 mg. g FW -1 for FDI nd FU regimes, respectively, nd we did not oserve ny significnt difference etween DDI nd FDI regimes. Tle 2: Physiologicl prmeters of young olive trees mesured t three phonologicl stges nd under three different wter regimes. Phenologicl stges Irrigtion regimes LProlC (mg. g FW -1 ) LTCC (mg. ml -1 ) LProtC (mg. mg FW -1 ) LSSC (mg. g FW -1 ) FDI 15.4 22.7 14.2 160.6 Flowering DDI 17.2 22.4 14.8 174.4 FU 21.1 16.4 14.9 185.3 P (α=5%) 0.018 <0.001 0.402 0.023 FDI 20.1 15.1 18.6 162.5 Fruit set DDI 20.3 14.6 18.7 195.5 FU 23. 6 13.1 23.3 242.5 c P (α=5%) 0.03 0.045 0.013 0.004 FDI 12.3 23.3 37.2 289.2 Fruiting DDI 16.3 21.1 41.4 290.9 FU 31.1 18.2 54.3 350.1 P (α=5%) 0.015 0.015 0.001 0.001 Vlues with the sme letter do not differ significntly etween the irrigtion regimes for given penologicl stge (P> 0.05) Stomtl conductnce: The verge vlues of stomtl conductnce mesured t flowering, fruit set, nd fruiting stges re shown in figure 2. Significnt vritions were recorded mong the three irrigtion regimes during the three phenologicl stges. The high nd low vlues were recorded under FDI nd FU regimes, respectively. 300 250 200 c c c 150 100 50 0 FDI DDI FU FDI DDI FU FDI DDI FU Flowering Fruit set Fruiting Irrigtion regimes X phenologicl stges Figure 2: Stomtl conductnce of young olive trees in reltion with irrigtion regimes Totl minerl leves content (TMLC): The totl minerl content in leves of the young olive trees mesured t fruiting stge vried significntly with the vrition of the irrigtion regimes (Figure 3). The highest men vlues of TMLC were oserved under full drip irrigtion, while the lowest were otined under flood irrigtion.
TMLC (% FM) 2,5 2 1,5 1 0,5 0 FDI DDI FU Irrigtion regimes Figure 3: Totl minerl leves content of young olive trees in reltion with irrigtion regimes Discussion In the semi rid re where the experiment ws crried out proper mngement of irrigtion wter, such s the ppliction of deficit irrigtion, increses wter use efficiency nd decreses wter consumption. However, wter stress cuses chnges in numer of physiologicl nd iochemicl processes governing plnt growth nd productivity (Alexiev et l., 2001). Our results showed tht t the three phenologicl stges, the LRWC depended on the irrigtion regime. The lowest vlues of this prmeter were recorded under FU regime, ecuse the low frequency of irrigtion with high mounts of wter in summer under high tempertures certinly incresed the loss of wter y percoltion nd evportion nd creted the conditions of wter deficit in the root zone. The stomtl conductnce ws negtively ffected y FU regime. Fernádez (1997) showed tht the olive tree is le to restrict wter loss y closing its stomt. DDI induced stomtl close in comprison with FDI. This is in reltion with the soil wter potentil which controlled significntly stomtl conductnce (Lu nd Zhng 1999). We noted tht FU regime induced significnt increse in ccumultion of proline nd sugr in leves. The proline ccumultion is frequently oserved during drought stress nd is thought to ply multifunctionl role in defence mechnisms ( Boussdi et l., 2013). Sugrs re lso mong the importnt osmolytes contriuting to the osmotic djustment of plnts under wter or sline stress (Ashrf nd Hrris, 2004). A significnt decrese in LCC ws shown under FU regime in comprison with drip irrigtion regimes. In generl, this decrese is relted to wter deficit which occurred under flood irrigtion nd cused decrese in the concentrtion of chlorophyll pigments in the leves of young olive trees. This phenomenon cn e explined either y the degrdtion of the pigments y the hydrolytic enzymes, or y the inctivtion of the iosynthesis of these pigments (Frooq et l., 2009). We noted n increse in proteins ccumultion under FU regime t fruit set nd fruiting stges. Glu nd closed (1992) reported tht wter deficit induced n increse in proteins content in olive trees y n increse of nitrogen (Grg, 2003). This induction of proteins y wter deficit depends on the stge nd the genotype of the tree (Riccrdi et l., 1998). The totl minerl content in leves of the young olive trees vried significntly with irrigtion regimes nd the highest vlues were noted under FDI, while the lowest were otined under FU regime which induce limittion in nutrient uptke nd decresing their concentrtions in leves tissue. Simulr results were reported y Mehnn et l., (2012) when the pplied wter stress on olive orchrd. We conclude tht deficit drip irrigtion did not induce significnt effect on ll physiologicl prmeters mesured in comprison with full drip irrigtion. It llowed
30% of wter sving compred to full drip irrigtion nd 80% of wter sving compred to flood irrigtion techniques. References Alexiev V., Sergiev I., Mpelli S, Krnov E. 2001. The effect of drought nd ultrviolet rdition on growth nd stress mrkers in pe nd whet. Plnt Cell Environ 24: 1337 1344. Arnon D.I. 1949. Copper enzymes in isolted chloroplsts: ployphenol-oxydse in Bet vulgris L. Plnt Physiol. 24:1-15. Ashrf M., Hrris P.J.C. 2004. Potentil iochemicl indictors of slinity tolernce in plnts. Plnt. Sci. 166: 3-16. Btes L., Wldren R.P., Tere J.D. 1973. Rpid determintion of free proline for wter stress studies. Plnt Soil. 39:205-207. Boussdi O., Bchir A., Steppe K., Vn Leke M.C, Lemeur R., BrhmM. 2013. Active nd pssive osmotic djustment in olive tree leves during drought stress. Europen Scientific Journl. Vol.9, No.24, 423-439. Brdford M.M. 1976. A rpid nd sensitive method for the quntifiction of microgrm quntities of protein utilizing. The principle of protein dye inding. Anl. Bioch. 72: 248-257. Duois F., Gilles K.A, Hmilton J.K., Reers P.A. Smith F. 1956. Colorimetric method for determintion of sugrs nd relted sustnces. Anl. Chem. 28: 350-356. Frooq, M., Whid, A., Koyshi, N., Fujit, D., Bsr, S.M.A., (2009). Plnt drought stress: effects, mechnisms nd mngement. Agron. Sustin. Dev., 29: 185 212. Fereres E. nd Goldhmer D. 1990. Decious ruit nd nut tress, p. 987-1017. In: B.A. Stewrdt nd D.R. Nielsen (eds.). Irrigtion of Agriculturl Crops-Agronomy Monogrph N. 30 Amer.Soc.Agron., Mdison. Fernández J.E., Moreno F., Girón I.F., Blázquez O.M. 1997. Stomtl control of wter use in olive tree leves. Plnt nd Soil 190: 179-192. Fisher G, Shh M, vn Velthuisen H., 2002. Climte chnge nd griculturl vulnerility. Vienn (Austri): IIASA. Glu, G., Close, T.J., 1992. Sequence of the cotton group 2 LEA/ RAB/ dehydrin proteins en coded y le3 cdncs. Plnt physiology. 98: 1523-1525. Grg B.K., 2003. Nutrient uptke nd mngement under drought: nutrient-moisture interction. Curr. Agric. 27: 1 8. Lu C. Zhng, J. 1999. Effect of wter stress on photosystem II photochemistry nd its thermostility in whet plnts. Journl of Experimentl Botny, Vol. 50, N 336: 1199-1206. Mkel P., Munns R., Colmer T.D., Condon A.G., Peltonen-Sinio P. 1998. Effect of folir pplictions of glycineetine on stomtl conductnce, scissic cid nd solute concentrtions in leves of slt or drought-stressed tomto. Aust. J. Plnt physiol. 25: 655-663. Mehnn H.T., Stino, R.G., Ikrm, S.E., Gd El-Hk, A.H. 2012. The Influence of Deficit Irrigtion on Growth nd Productivity of Mnznillo Olive Cultivr in Desert Lnd. Journl of Horticulturl Science & Ornmentl Plnts 4 (2): 115-124, 2012 Orgz F. nd Fereres E. 1997. El cultivo del olivo. In: D. Brrnco, R., Fernández-Escor nd L. Rllo (eds).. Mundi Prens, Mdrid. p. 251-272 Riccrdi F., Gzeu, P., De Vienne D., Zivi, M. 1998. Protein chnges in response to progressive wter deficit in mize: quntittive vrition nd polupeptide identifiction. Plnt physiology. 117: 125-126. Tognetti R., d'andri R., Lvini A., Morelli G., 2006. The effect of deficit irrigtion on crop yield nd vegettive development of Ole europe L. (cvs. Frntoio nd Leccino). Europen Journl of Agronomy, 25: 356-364.