Impaginato 87 Adv. Hort. Sci., 2019 33(1): 87-95 doi: 10.13128/ahs-23794 Comparison of salinity effects on graf- ted and non-grafted eggplants in terms of ion accumulation, MDA content and antioxidative enzyme activities M. Talhouni 1 (*), K. Sönmez 2, S. Kiran 3, R. Beyaz 4, M. Yildiz 5, Ş. Kuşvuran 6, Ş.Ş. Ellialtıoğlu 7 1 National Agricultural Research Center (NARC), Horticulture Directorate, Amman, Jordan. 2 Eskişehir Osmangazi University, Faculty of Agriculture, Department of Horticulture, Eskişehir, Turkey. 3 Soil, Fertilizer and Water Resources Central Research Institute, Ankara, Turkey. 4 Ahi Evran University, Faculty of Agriculture, Department Soil Science and Plant Nutrition, Kırşehir, Turkey. 5 Ankara University, Faculty of Agriculture, Department of Agronomy, Ankara, Turkey. 6 Cankiri Karatekin University, Kizilirmak Vocational High School, Cankiri, Turkey. 7 Ankara University, Faculty of Agriculture, Department of Horticulture, Ankara, Turkey. Key words: APX, CAT, eggplant, lipid peroxidation, naCl, na+, Cl-, K+, Ca++, scion/rootstock combination, Sod. Abstract: Grafting onto resistant/tolerant rootstocks is known to alleviate the negative effects of abiotic stress factors like salinity by enhancing their enzy- matic antioxidant defense system and having more efficient nutrient uptake. T h i s s t u d y w a s c a r r i e d o u t u n d e r g r e e n h o u s e c o n d i t i o n s , d i f f e r e n t rootstock/scion eggplant combinations were grown under two salinity treat- ments 1.8-2 dS/m (control) and 6-7 dS/m (stress) with seven eggplant geno- types as rootstocks (commercial and Turkish genotypes). Two genotypes were used as the scion. Leaf MDA and ions (Na+, Cl-, K+ and Ca++) content, antioxidant enzymes activity were evaluated as indicators for plant tolerance level. It was found that the rootstock-grafted plants were more efficient in preventing Na+ ions to be transferred to the plants upper parts and had higher SOD, CAT, and APX activity levels compared to the self- and non-grafted plants which resulted in better tolerance and growth in these plants. 1. Introduction eggplant (Solanum melongena l.) is an important vegetable crop (*) Corresponding author: manar.alhouni@gmail.com Citation: TAlHouni M., SönMez K., KirAn S., BeyAz r., yildiz M., KuşvurAn ş., elliAlTioğlu ş.ş., 2019 - Comparison of salinity effects on grafted and non-grafted effplants in terms of ion accumula- tion, MDA content and antioxidative enzyme acti- vities. - Adv. Hort. Sci., 33(1): 87-95 Copyright: © 2019 Talhouni M., Sönmez K., Kıran S., Beyaz r., yıldız M., Kuşvuran ş., ellialtıoğlu ş.ş. This is an open access, peer reviewed article published by Firenze university Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting information files. Competing Interests: The authors declare no competing interests. received for publication 9 April 2018 Accepted for publication 12 december 2018 AHS Advances in Horticultural Science Adv. Hort. Sci., 2019 33(1): 87-95 88 worldwide, its production reaches about 48.5 million ton while in Turkey eggplant production reaches 800- 900 thousand tons (TuiK, 2015). one of the most stress factors that affect eggplant production is salini- ty. Salinity is a major environmental factor limiting plant growth and productivity, especially in the arid a n d s e m i a r i d r e g i o n s ( P a r i d a a n d d a s , 2 0 0 5 ) . Conflicting literature exists on eggplant tolerance to soil salinity and this difference could be related to the varieties or cultivars used and to the different environmental conditions in those studies (Ünlükara et al., 2010). overcoming salt stress problems would have a positive impact on agriculture production. Attempts have been made to improve salt tolerance of crops by traditional breeding programs but with limited success due to the complexity of the trait (Flowers, 2004). even the use of genetic transformation of plants to raise their tolerance, despite its success in some cases (rus et al., 2001); the complexity of the trait and lack of public acceptance, limiting its wide spread and use (Munns, 2002). one way of avoiding or reducing losses in production caused by salinity would be to use the tolerant rootstocks. in relation to salt tolerance, many studies have been conducted to determine the response of grafted plants to salini- ty. According to these studies, the improvement of salt tolerance by grafting is related to the capability of rootstocks to reduce toxicity of na+ and/or Cl- through exclusion and/or reduction of absorption of Cl- by the roots, and the replacement or substitution of total K+ by total na+ in the foliage (estañ et al., 2005; Martinez-rodriguez et al., 2008). it is supposed that useful rootstocks should be able to reduce the uptake and transport of saline ions to the shoot, which will slow or prevent the accumulation of the toxic salt ions in the leaves (usanmaz and Abak, 2018). Salt stress causes a range of adverse effects in plants, mainly ionic disorders, osmotic stress and nutritional imbalance. A common feature of these effects is the overproduction of reactive oxygen species (roS) such as singlet oxygen (1o2), superoxide anion (o2−), hydrogen peroxide (H2o2), and hydroxyl radical (oH) which are highly reactive and toxic and cause damage to proteins, lipids, carbohydrates and dnA which ultimately results in oxidative stress (Ashraf and Foolad, 2007). Salt stress causes stomatal closure, which reduces the Co2/o2 ratio inside leaf tissues and inhibits Co2 fixation (Hernández et al., 2000). Plants antioxidant enzymes such (superoxide dismutase, Sod; catalase, CAT; ascorbate peroxidase, APX; glutathione reductase, Gr; monodehydroascor- bate reductase, MdHAr; dehydroascorbate reduc- tase, dHAr; glutathione peroxidase, GPX; guaicol peroxidase, GoPX and glutathione-S- transferase, GST) work in concert to control the cascades of uncontrolled oxidation and protect plant cells from oxidative damage by scavenging of roS (Scandalios, 1997; dixit et al., 2001; Shalata et al., 2001). Superoxide dismutase (Sod) reacts with the superoxide radical at almost diffusion-limited rates to produce H2o2 (Scandalios, 1993). H2o2 is scavenged by peroxidases, especially ascorbate peroxidase (APX), and catalase (CAT). in the present study, we exposed non-grafted, self-grafted and rootstock-grafted eggplants to con- ditions of salt stresses to investigate whether grafted plants could improve tolerance to salinity by alleviat- ing the expression of antioxidant enzymes. using local genotypes in breeding programs is of vital importance to find new rootstocks with the abil- ity to alleviate the effects of salinity and reduce its effect on plant growth and productivity. in the present study, two eggplant genotypes were grafted onto seven rootstocks to compare the ability of the different rootstock genotypes in increasing eggplant tolerance as it is related to the ability of the rootstock to 1) control the transport of na+ and Cl-, 2) to maintain better K+ and Ca++ uptake, 3) to increase the enzymatic defense mechanism scavenging the roS induced by oxidative stress resulting in less leaf malodialdehyde (MdA) content. Another goal was to evaluate the potential of the Turkish genotypes Burdur and Mardin as rootstocks under salinity conditions in comparison to the com- mercial genotypes. 2. Materials and Methods The field part of the experiment was carried out between August-november 2014, in a 300 m2 plastic house belongs to the private sector (Genta General Agricultural Products Marketing Co.) in Antalya- Turkey while laboratory works and analysis were car- ried out in Ankara university Faculty of Agriculture, departments of Horticulture and Agronomy laborato- ries. Plant material Two eggplant (Solanum melongena l.) genotypes, naomi F1 cv., a commercial cultivar, and Artvin, a salt sensitive breeding line, were used as scions. And for rootstocks five commercial genotypes were used, Talhouni et al. - Salinity effects on grafted and non-grated effplants 89 AGr703 (Solanum aethiopicum), Köksal F1, yula F1 and vista (S. incanum x S. melongena hybrids), and Hawk (S. torvum), these genotypes are the most common used rootstocks in grafting eggplants due to their tolerance. in addition two local salt-tolerant genotypes Burdur and Mardin (S. melongena l.) were used as rootstocks, their tolerance to salinity were confirmed in previous studies screening for Turkish tolerant genotypes (yaşar, 2003). Grafting and salt treatment eggplant seeds were sown in germination trays filled with 2:1 peat:perlite. After sowing trays were kept under controlled conditions of temperature (25°C) and humidity (80%). When the seedlings reached 2-4 true leaves stage, grafting was carried out. The tube-grafting was used in this study because i t i s t h e m o s t w i d e l y u s e d g r a f t i n g m e t h o d i n Solanaceae family (rivard et al., 2009). Then grafted seedlings were kept under controlled conditions of humidity (90%) for four days, then seedlings were transferred to the greenhouse under shading before planting for acclimatization. Ten days after grafting seedlings were placed in the plastic house and were ready for transplantation in 8 l plastic pots filled with 3:1 perlite:vermiculite. in one of our earlier studies we examined these genotypes tolerance under salinity conditions at seedling stage in a hydroponic experiment (Talhouni, 2016), in this study we wanted to assess these same genotypes at flowering and fruit set stage. When plants reached the flowering and fruit set stage salin- ity treatment began. 6-7 dSm-1 water eC was used as the stress treatment by solving naCl into the nutri- tion solution; according to the volume of barrels used in fertigation about 8 kg of iodine-free sodium chloride were required , while for the control the eC level was kept at 1.8-2 dSm-1 (no naCl was added). Leaf ion concentrations After 60 days from salinity stress application, samples were taken from the control and the salinity treated plants for the different analysis. For the leaf- na+, Cl-, K+ and Ca++ concentration measurements, leaves were dried at 65°C for 48 hours, grounded, dissolved in 1% (v/v) HCl. For the analysis of na+, K+ and Ca++ contents, atomic absorption spectropho- t o m e t e r ( v a r i a n S p e c t r a A A 2 2 0 F S ) w a s u s e d (Kuşvuran, 2012). While for Cl-, titration procedure was followed as described by Taleisnik et al. (1997) using Buchler - Cotlove chloridometer. Enzyme extractions and assays Fresh leaf samples were submersed for 5 min in liquid nitrogen. The frozen leaves were kept at -80°C for further analyses. enzymes were extracted from 0.5 g leaf tissue using a mortar and pestle with 5 ml extraction buffer containing 50 mM potassium phos- phate buffer, pH 7.6 and 0.1 mM na-edTA. The homogenate was centrifuged at 15,000 g for 15 min and the supernatant fraction was used to assay for the various enzymes. All steps in the preparation of enzyme extracts were performed at 4°C. APX activity was determined by measuring the consumption of ascorbate by following absorbance at 290 nm. one unit of APX activity was defined as the amount of enzyme required to consume 1 μmole ascorbate min-1 (Cakmak and Marschner, 1992). S o d w a s a s s a y e d a c c o r d i n g t o C a k m a k a n d Marschner (1992), by monitoring the superoxide rad- ical-induced nitro blue tetrazolium (nBT) reduction at 560 nm. one unit of Sod activity was defined as the amount of enzyme which causes 50% inhibition of the photochemical reduction of nBT. Catalase (CAT) activity was measured as the decline in absorbance at 240 nm due to the decom- position decline of extinction of H2o2. The reaction was started by adding H2o2. Lipid peroxide content lipid peroxidation was measured as the amount of malondialdehyde (MdA) determined by the thio- barbituric acid (TBA) reaction. Frozen samples were homogenized in a pre-chilled mortar with two vol- umes of ice-cold 0.1% (w/v) tricloroacetic acid (TCA) and centrifuged for 15 min at 15000 x g. Assay mix- ture containing 1 ml aliquot of the supernatant and 2 ml of 0.5% (w/v) thiobarbituric acid in 20% (w/v) tri- cloroacetic acid (TCA) was heated to 95°C for 30 min and then rapidly cooled in an ice-bath. After centrifu- gation (10000 x g for 10 min at 4°C), the supernatant absorbance (532 nm) was read and values corre- sponding to non-specific absorption (600 nm) were subtracted. The MdA content was calculated accord- ing to the molar extinction coefficient of MdA (155 mM-1 cm-1). Statistical analysis randomized complete block design with three replicates was used. each replicate included 108 pots (18 rootstock/scion combination * 2 salinity level * 3 plants of each combination) with one plant/pot. data were subjected to duncan’s multiple range tests Adv. Hort. Sci., 2019 33(1): 87-95 90 using the SAS program (P≤0.01)(version 6.12, SAS institute inc., Cary, uSA). 3. Results Na+ concentrations in general, the concentrations of na+ in the leaves increased significantly due to increased naCl concen- tration (Table 1) with significant differences between grafting combinations, and a significant ‘salinity x scion/rootstock combination’ interaction at P≤0.01. After 60 days of salinity stress application, the combinations that showed the least concentrations o f n a + i n t h e i r l e a v e s w e r e ; ( r o o t s t o c k / s c i o n ) K ö k s a l / A r t v i n , v i s t a / n a o m i , K ö k s a l / n a o m i , AGr703/naomi and AGr703/Artvin (9.75, 9.65, 9.92 1 0 . 0 2 a n d 1 0 . 4 6 µ g / m g F W r e s p e c t i v e l y ) w i t h increase rates of 3511, 1035, 4623, 1721, 3506% respectively (Fig. 1) which indicated that these root- stock genotypes could limit na+ to the leaves more successfully. no significant effects of grafting per se were noticed, no differences were observed between non-grafted and self-grafted combinations. Cl- concentration As in leaf na+ concentration, leaf Cl- concentration also increased significantly under salinity treatment in all combinations, with a significant differences and a significant ‘salinity x scion/rootstock combination’ interaction at P≤0.01 (Fig. 1). The highest Cl- concen- t r a t i o n w a s o b s e r v e d i n A r t v i n , n a o m i , (rootstock/scion) Artvin/Artvin, naomi/naomi, Mardin/Artvin, Mardin/naomi (11.83, 10.81, 9.54, 9.06, 8.83 8.12 µg/mg FW) combinations, while the lowest was observed Köksal/Artvin, AGr703/Artvin, AGr703/naomi and Burdur/Artvin (5.06, 5.06, 5.27, 5.49 µg/mg FW respectively) and there were no sig- nificant differences between non- and self-grafted combinations (Table 1). K+ concentrations The amounts of K ion measured in leaf samples taken from plants treated with eC 6-7 dS / m naCl gave lower values in some combinations than control plants (Table 1), the highest decrease in leaf K+ con- tent was observed in non-grafted Artvin (-9.82%).fol- lowed by (rootstock/scion) Artvin/Artvin with decrease rate of (-6.25%) (Fig. 1). The highest values were obtained from (rootstock/scion); Köksal/Artvin, Köksal/naomi, Mardin/naomi, AGr703/Artvin, yula/naomi (4.86, 4.64, 4.36, 4.30, 4.27 µg/mg FW, respectively) (Table 1). Among these combinations, Köksal/Artvin, AGr703/Artvin and yula/naomi had the highest K+ ions increase rate (47.27%, 22.16%, 20.96%) (Fig. 1). Combinations that gave the lowest K+ ion amount measurements were (rootstock/scion) Hawk/Artvin, naomi, Burdur/naomi, naomi/naomi, Table 1 - leaf ions concentration (µg/mg FW); in the different grafting combinations under control and salinity treatments Grafting combination na+ K+ Ca++ Cl- Control Salinity Control Salinity Control Salinity Control Salinity Köksal/Artvin 0.27±0.00 a 9.75±0.25 a 3.30±0.15 ab 4.86±0.33 b 0.50±0.03 f 0.48±0.03 e 0.06±0.02 a 5.06±0.64 a AGr703/Artvin 0.29±0.03 a 10.46±0.53 a-c 3.52±0.34 a-c 4.30±0.26 ab 0.49±0.02 f 0.41±0.04 de 0.06±0.02 a 5.06±0.90 a vista/Artvin 0.51±0.03 ab 12.14±0.86 b-e 3.89±0.11 a-e 3.93±0.53 a 0.46±0.02 b-f 0.41±0.03 de 0.12±0.04 a-d 6.30±1.10 a-c yula/Artvin 0.24±0.02 a 11.08±0.58 a-e 3.74±0.18 a-e 3.89±0.12 a 0.43±0.01 a-c 0.35±0.03 b-d 0.19±0.02 c-f 6.63±0.75 a-d Burdur/Artvin 0.49±0.01 b 10.91±0.53 a-d 3.57±0.12 a-c 3.97±0.24 a 0.49±0.02 ef 0.39±0.05 c-e 0.09±0.03 ab 5.49±0.13 ab Mardin/Artvin 0.61±0.09 b-d 12.36±0.29 c-e 3.70±0.23 a-d 4.22±0.09 ab 0.44±0.01 a-d 0.35±0.06 b-d 0.14±0.03 a-e 8.83±1.08 c-f Hawk/Artvin 0.26±0.05 a 10.89±0.18 a-d 4.05±0.28 c-e 3.84±0.31 a 0.46±0.02 c-f 0.41±0.03 de 0.11±0.02 a-c 6.45±1.50 a-d Artvin/Artvin 0.83±0.08 e-g 12.36±0.70 c-e 4.32±0.05 de 4.05±0.15 ab 0.41±0.01 a 0.35±0.02 b-d 0.19±0.02 c-f 9.54±1.21 e-g Artvin 0.88±0.04 fg 12.77±0.46 de 4.38±0.28 e 3.95±0.13 a 0.40±0.01 a 0.29±0.02 ab 0.22±0.02 ef 11.83±0.62 g Köksal/naomi 0.21±0.02 a 9.92±0.37 ab 4.11±0.22 c-e 4.64±0.23 ab 0.49±0.02 d-f 0.31±0.01 a-c 0.09±0.04 ab 6.06±0.38 ab AGr703/naomi 0.55±0.12 ab 10.02±1.26 ab 3.87±0.06 a-e 3.96±0.28 a 0.48±0.01 d-f 0.36±0.02 b-d 0.10±0.04 a-c 5.27±0.55 a vista/naomi 0.85±0.05 fg 9.65±0.71 a 3.67±0.15 a-d 4.15±0.08 ab 0.44±0.02 a-e 0.36±0.02 b-d 0.15±0.03 b-f 6.13±0.19 ab yula/naomi 0.73±0.04 d-f 10.93±0.97 a-d 3.53±0.10 a-c 4.27±0.29 ab 0.42±0.01 a-c 0.25±0.02 a 0.18±0.05 b-f 7.51±0.54 a-e Burdur/naomi 0.49±0.05 b 11.14±1.16 a-e 3.50±0.36 a-c 3.88±0.23 a 0.48±0.01 d-f 0.40±0.01 c-e 0.13±0.01 a-d 6.37±1.01 a-c Mardin/naomi 0.68±0.04 c-e 12.07±0.13 b-e 3.95±0.32 b-e 4.36±0.24 ab 0.43±0.01 a-c 0.34±0.03 a-d 0.14±0.03 a-e 8.12±0.63 b-e Hawk/naomi 0.80±0.10 e-g 11.14±1.20 a-e 3.80±0.11 a-e 4.09±0.27 ab 0.41±0.01 ab 0.35±0.01 b-d 0.20±0.02 d-f 7.29±0.24 a-e naomi/naomi 0.94±0.04 g 12.34±0.84 c-e 3.33±0.20 ab 3.96±0.36 a 0.40±0.01 a 0.34±0.01 a-d 0.22±0.02 ef 9.06±1.06 d-f naomi 0.52±0.06 ab 13.30±0.73 e 3.27±0.29 a 3.85±0.30 a 0.40±0.02 a 0.28±0.03 ab 0.23±0.03 f 10.81±1.41 fg Cv (%) 43.07 9.78 8.81 6.83 8.01 15.22 38.38 27.17 Treatment ** ** ** ** Combination ** ** ** ** Combination x treatment ** ** ** ** Talhouni et al. - Salinity effects on grafted and non-grated effplants 91 AGr703/naomi, Artvin (3.84, 3.85, 3.88, 3.96, 3.96, 3.96 85 µg/mg FW). no significant differences were obtained for self-grafted combinations. Ca++ concentrations eC 6-7 dSm-1 naCl treatment led to a decrease in leaf Ca++ concentration in all combinations (Fig. 1) with significant differences between treatments and combination (P≤0.01) and with a significant ‘salinity x scion/rootstock combination’ interaction. The high- est leaf Ca++ concentrations were obtained in (root- s t o c k / s c i o n ) A G r 7 0 3 / A r t v i n , K ö k s a l / A r t v i n , Burdur/naomi, Hawk/Artvin and vista/Artvin (0.48, 0.42, 0.41, 0.41 µg/mg FW, respectively). no signifi- cant effects were observed in self-grafted combina- tions. Antioxidant enzyme activities Salt treatments increased superoxide dismutase (Sod) activities in all of the plants (Table 2). However, Fig. 1 - leaf ions concentration (µg/mg FW); in the different grafting combinations under control (blue) and salinity treatments (red). Table 2 - Sod, CAT, and APX enzymes activities (µmol/g FW) in the different grafting combinations under control and salinity treat- ments eggplant Sod CAT APX MdA Control Salinity Control Salinity Control Salinity Control Salinity Köksal/Artvin 217.03±8.00 a 635.46±27.84 gh 139.90±13.74 ab 593.91±28.44 h 2042.77±12.67 h 5387.96±560.98 e 5.12±0.29 a-d 10.44±0.54 a AGr703/Artvin 207.06±6.28 a 645.64±38.29 h 129.82±10.00 ab 576.91±27.73 gh 2020.91±97.38 h 4820.66±545.40 de 5.02±0.13 ad 10.23±1.24 a vista/Artvin 215.92±11.75 a 464.88±44.39 c-f 113.03±11.99 a 484.17±25.96 c-f 1758.36±28.48 e-h 3829.29±568.57 a-d 4.86±0.27 ab 12.83±0.26 ab yula/Artvin 193.54±6.29 a 414.49±26.02 b-d 103.86±6.46 a 409.13±1.88 bc 1765.71±141.18 e-h 3307.96±550.14 a-c 5.12±0.26 a-d 10.14±0.61 a Burdur/Artvin 208.97±10.32 a 508.88±55.72 d-f 131.44±4.26 ab 548.67±19.02 e-h 1882.51±52.64 f-h 3839.81±57.28 a-d 5.19±0.10 a-d 11.16±0.44 a Mardin/Artvin 195.91±10.91 a 470.99±16.48 c-f 138.76±14.25 ab 434.69±6.55 b-d 1395.16±235.41 b-d 3105.27±93.76 ab 5.49±0.25 a-e 11.50±0.21 a Hawk/Artvin 203.44±10.29 a 436.05±50.00 b-e 118.68±15.42 a 464.12±25.38 c-e 1926.37±199.83 gh 4303.30±32.77 b-e 4.80±0.31 a 11.95±0.98 ab Artvin/Artvin 186.29±10.04 a 341.33±58.60 ab 123.87±6.38 ab 350.16±52.43 ab 1134.59±102.54 ab 2731.28±37.49 a 6.32±0.13 fg 12.54±0.15 ab Artvin 189.95±12.89 a 295.15±16.97 a 113.49±7.29 a 374.84±27.07 b 903.43±37.94 a 2614.61±37.06 a 6.34±0.33 g 14.81±1.23 b Köksal/naomi 190.92±25.52 a 553.92±32.30 f-h 116.33±14.37 a 553.17±30.84 f-h 1968.59±112.34 g-h 4427.68±48.03 c-e 4.95±0.18 a-c 10.93±1.20 a AGr703/naomi 213.81±4.16 a 491.39±39.05 d-f 165.69±17.37 b 503.21±14.17 d-g 1924.53±144.55 gh 4326.69±614.68 b-e 4.87±0.23 ab 10.54±1.04 a vista/naomi 194.09±17.87 a 457.84±29.92 c-f 124.91±15.83 ab 405.95±29.79 bc 1547.82±154.87 c-f 3072.32±48.96 ab 5.59±0.25 b-f 11.18±0.16 a yula/naomi 200.41±10.91 a 427.66±11.33 b-e 99.34±6.30 a 401.18±19.92 bc 1499.31±168.98 c-e 3663.61±635.13 a-d 5.26±0.28 a-d 11.06±0.93 a Burdur/naomi 196.48±16.49 a 534.86±35.10 e-g 117.08±28.01 a 503.48±27.99 d-g 1813.06±32.67 e-h 3789.02±90.92 a-d 5.09±0.39 a-d 10.36±0.85 a Mardin/naomi 191.44±20.27 a 378.05±10.08 a-c 104.70±15.90 a 367.67±14.99 ab 1608.48±112.47 d-g 3448.81±529.02 a-c 5.71±0.19 d-g 10.86±0.74 a Hawk/naomi 193.35±9.53 a 421.65±43.89 b-d 140.49±24.51 ab 360.07±7.01 ab 1695.49±80.45 d-h 4471.40±613.60 c-e 4.80±0.12 a 10.89±0.92 a naomi/naomi 201.11±19.08 a 272.74±22.75 a 125.68±6.97 ab 366.67±43.39 ab 1205.04±58.49 a-c 2693.56±51.33 a 6.05±0.16 e-g 14.66±2.05 b naomi 199.68±10.99 a 271.57±36.99 a 123.98±8.26 ab 289.02±39.88 a 1033.83±54.71 ab 2782.04±593.00 a 5.66±0.18 c-g 14.91±1.65 b Cv (%) 4.65 24.53 12.87 19.94 21.9 21.7 9.37 13.58 Treatment (T) ** ** ** ** Combination (C) ** ** ** ** C x T ** ** ** ** 92 Adv. Hort. Sci., 2019 33(1): 87-95 in the rootstock-grafted plants, Sod activity increased faster and with higher rates than in the non- and self- grafted plants. Köksal/Artvin and AGr703/Artvin had the highest Sod activity level (645.64 and 635.46 u m o l / m i n / m g F W r e s p e c t i v e l y ) . F o l l o w e d b y Köksal/naomi, Burdur/naomi, and Burdur/Artvin c o m b i n a t i o n s ( 5 5 3 . 9 2 , 5 3 4 . 8 , a n d 5 0 8 . 8 8 umol/min/mg FW respectively). The highest increase rate in Sod activity was obtained for AGr703/Artvin combination (211.8%) while naomi/naomi and naomi combinations had the lowest increase with rates of 35.62 and 36% respectively (Fig. 2). naomi and self-grafted plants had the lowest values of the enzyme activity with no significant differences between non- and self-grafted combinations. Catalase (CAT) activity increased under salt treat- ment in all combinations compared to the control plants (Table 2), (rootstock/scion) Köksal/Artvin and AGr703/Artvin had the highest CAT activity (593.91 and 576.91 μmol/min/mg FW respectively). Followed by Köksal/naomi, Burdur/Artvin, AGr703/naomi and Burdur/naomi. on the other hand Artvin and naomi (non-grafted) and the self-grafted plants had the low- est CAT activity. Burdur/naomi had the highest increase rate in CAT activity (330%) while non-graft- ed naomi had the lowest rate (133%) (Fig. 2). no sig- nificant differences were observed between non- and self-grafted combinations. under naCl-salinity conditions, ascorbate peroxi- dase (APX) activity was increased in all plants (Fig. 2). However, AGr703/Artvin and Köksal/Artvin had the highest APX activity levels indicating their better tol- erance level (4820.66 and 5387.96 μmol/min/mg FW respectively) as shown in Table 2, while the lowest APX enzyme activity was found in non-grafted plants naomi and Artvin indicating their poor tolerance. no significant differences were obtained between non- and self-grafted combinations. Malondialdehyde (MDA) Salinity resulted in a significant increase on the MdA content compared to the controls due to oxida- tive stress induced peroxidation (Fig. 2). With regard to the MdA, significant differences were found among grafting combinations and a significant ‘salini- ty x rootstock/scion combination’ interaction at P≤0.01 (Table 2). According to the results naomi, naomi/naomi and Artvin were found to be more sen- sitive with MdA content increase rate of 163.4, 142.3, 133.6% respectively (Fig. 2). no significant dif- ferences were observed between non- and self-graft- ed combinations. 4. Discussion and Conclusions As a result of high salinity level, na+ and Cl- ions can be accumulated in toxic levels in plant tissues depends on the plant species. even though these two ions are suitable for osmotic adjustment, excess con- centrations will be toxic enough to prevent plant growth. in the study, combinations vista/Artvin, Köksal/Artvin, vista/naomi, and Köksal/naomi had less na+ accumulation in their tissues which indicates that these combinations were able to keep na+ ions a w a y f r o m t h e i r l e a v e s . C o n c e r n i n g l e a f C l -, vista/Artvin combination had the least concentra- tion. Grafted plants tend to hold na+ and Cl- ions in their root tissues preventing them from being translocated to the shoots and leaves in high concen- Fig. 2 - Sod, CAT and APX enzymes activities (µmol/g FW) in the different grafting combinations under control (blue) and salinity treatments (red). Talhouni et al. - Salinity effects on grafted and non-grated effplants 93 trations (levitt, 1980; estañ et al., 2005). Most veg- etables like, cucumbers, melons, tomatoes and egg- plant are injured by excess na+ ions (Tester and davanport, 2003). in Giuffrida et al. (2009), increased naCl level led to na+ concentration increase in toma- to leaves and fruits. Kuşvuran et al. (2007), under salinity conditions na+ and Cl- were accumulated in higher rates in the salinity-sensitive melon plants compared to the salinity-tolerant ones. K+ decrease rate was different between the differ- ent combinations. Akinci and lösel (2012), different eggplant genotypes showed different tolerant level to salinity. Pala cv. showed better tolerance to salinity compared to Kemer and Aydın Siyahı cultivars with better K+/na+ ratio. yaşar et al. (2006), in tissue cul- ture study on eggplant, there was an increase in na+ and Cl- tissues concentrations with decrease in K+ and Ca++ due to salinity. However there were significant differences between different genotypes, the salinity- tolerant MK and BB showed higher K+ and Ca++ con- centrations compared to the salinity sensitive Gr and AH genotypes. Consequently MK and BB had higher K+ and Ca++ uptake decreased under stress treatment (Savvas and lenz, 2000). in a similar study on pepper, the same results were obtained (Aktaş et al., 2002). Combinations with the highest leaf Ca++ concen- t r a t i o n s u n d e r s a l i n i t y w e r e v i s t a / n a o m i , AGr703/naomi and Burdur/Artvin. And maybe for this reason Burdur genotype can be considered a potential rootstock for increasing eggplant tolerance against salinity. The decrease in Ca++ uptake due to naCl salinity was observed by many authors, and in contrary to K+, the decrease was not due to the com- petition between na+ and K+ at the absorption site on the root surface, it was always found because of the decline in the transpiration rate under stress condi- tions (Maggio et al., 2007). in Gao et al. (2005), under stress conditions of low temperatures (5°C) grafted eggplants maintained higher leaf Ca++ concentrations compared to the non-grafted plants which gave the grafted plants higher tolerance under such stress conditions. Plant adaptation to salinity may depend on differ- ent mechanisms, including the capacity to maintain high levels of antioxidants and/or through the induc- tion of antioxidant enzymes (Sod, CAT, Gr, and APX, etc.) (Sevengör, 2010). in the present study, root- stock-grafted plants had higher activity of antioxidant enzymes under salinity conditions, which was trans- lated to lower MdA content in their leaves which means these combinations, were less affected by the roS-induced lipid peroxidation and they were more tolerant to salinity than the non- and self-grafted plants. MdA content always found higher in salinity-sen- sitive plants compared to salinity-tolerant ones (yaşar, 2003; Kuşvuran et al., 2015) and a significant relation between MdA content and antioxidant enzymes activity is first proven by Shalata and Tal (1998). Meloni et al. (2001) in cotton, yaşar (2003) in eggplant, doğan (2004) in tomato, and Sevengör (2010) in pumpkin, all found that MdA content was low in plants with high antioxidant enzymes activity under salinity stress conditions. in this study, antioxidant enzymes activity showed a higher increase in rootstock-grafted plants com- pared to the non- and self-grafted plants, this increase was significantly different between grafting combinations. in another study where cucumber was grafted onto salinity-tolerant rootstock, H2o2 level w a s f o u n d t o b e l o w , w h e r e a s S o d , C A T , P o d enzymes activity level were found higher. öztekin and Tuzel (2011), CAT activity level differed according to the rootstock genotypes, but always was higher in the grafted plants compared to the non-grafted plants. All results indicated that grafting per se had no significant role in alleviating negative effects of salini- ty as there were no significant differences between non- and self-grafted combinations in all parameters measured in this study. in general, local genotypes (landraces) are adapt- ed to prevailing environmental conditions like salini- ty. in this work, the local Turkish genotype Burdur showed a good potential to compete commercial genotypes. on the other hand, Mardin was way behind and did not show enough potential in this study. Acknowledgements This research was supported by the Coordination u n i t o f t h e S c i e n t i f i c r e s e a r c h P r o j e c t s o f t h e university of Ankara (Project no: 15H0447001). References AKinCi ş., löSel d.M., 2012 - Plant water-stress response mechanisms, pp. 15-42. - in: rAHMAn i.M.M. (ed.) Water stress. inTech open Books, pp. 300. 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