SALT TOLERANCE AMONG DIFFERENT SUNFLOWER GENOTYPES

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1 Sarhad J. Agric. Vol.24, No.2, 2008 SALT TOLERANCE AMONG DIFFERENT SUNFLOWER GENOTYPES Mohammad Islam*, Sher Afzal**, Ijaz Ahmad*, Ahsan -ul-haq*** and Akhter Hussain**** ABSTRACT An experiment was carried out hydroponically in green house and laboratories of Saline Agriculture Research Centre, University of Agriculture, Faisalabad during for the identification of salt tolerant genotypes of sunflower (Helianthus annuus L.), as well as their characteristics. Nine genotypes were grown in aerated Hoagland s solution. Stepwise salinity was developed with NaCl to achieve final levels of 75, 150 and 225 mol m -3 salinity where as, control contained only Hoagland s solution. After 30 days of final salinity level development, plants were harvested and data was recorded. Sunflower genotype SF-187 and SF-177 performed better in both control and saline conditions. These genotypes showed better shoot and root growth by maintaining least concentration of Na + and higher concentration of K + in leaf sap resulting in better K + : Na +. Genotype CRN was most sensitive. It had minimum root and shoot growth, maximum accumulation of Na + in leaf sap and least K + : Na +. Key words: K + : Na + ratio, Salinity levels, salt tolerance, sunflower genotypes, yield INTRODUCTION Salinity and sodicity has affected about 10% of world s agricultural land (Szabolcs, 1991). Approximately 20 m ha land deteriorates to zero production every year (Malcolm, 1993) mainly due to salinization. In Pakistan about 6.67 m ha land is salt affected (Khan, 1998), out of which 60 % is saline sodic. The effect of salt stress on higher plants is complex and incompletely understood. The accumulation of ions in leaves under conditions of salt stress causes reduction in photosynthesis (Yeo et al. 1985) and growth (Gadallah, 1999). Excesses of Na + and Cl, the predominant ions in sodic soil, create high ionic imbalances that may impair the selectivity of root membranes (Bohra and Dörffling, 1993). Saline conditions can induce K + deficiency (Botella et al. 1997). Salt affected soils can be managed by reclamation, but due to less availability of good quality water, low soil permeability and high cost of amendments, this approach is not feasible on a large scale (Qureshi et al. 1990). Saline agriculture technology is an alternative approach for effective utilization of salt affected soils, which involves the cultivation of salt tolerant species or crop cultivars. This technology gives economic returns from salt affected soils and provide vegetative covers to soil which reduces evaporation and hence the rate of salinization (Qureshi and Barrett-Lennard, 1998). Assessing response of plants/crops to salinity under naturally saline condition is not feasible due to extreme variability in soil salinity both spatially and temporally (Richards, 1983). To avoid this problem, comparative differences for salt tolerance among crops/ varieties can be studied under artificially salinized control conditions. Different physiological traits such as selectivity for potassium, exclusion and/or compartmentation of sodium and chloride ions, osmotic adjustments by accumulation of organic solutes have also been related to salt tolerance of crops plants (Wyn Jones and Storey, 1981). In this perspective, the present study was planned to identify the sunflower genotypes showing tolerance to salinity at different salinity levels. The selected genotypes may be recommended for use by the farmers of salt affected areas according the intensity of salinity problem. MATERIALS AND METHODS The present research work was conducted hydroponically in green house and laboratories of Saline Agriculture Research Centre, University of Agriculture, Faisalabad during Healthy and uniform sized seeds of nine sunflower genotypes were received from Saline Agriculture Research Centre, Department of Soil Science, University of Agriculture, Faisalabad. These seeds were sown in gravel filled iron trays and kept moistened with distilled water. After emergence, the seedlings were sprinkled with a half strength Hoagland s solution (Hoagland and Arnon, 1950). At two-leaf stage the seedlings were transplanted to 200 L capacity iron tubs lined with polythene sheet containing ½ strength Hoagland s solution (Hoagland and Arnon, 1950). Five healthy plants of each genotype were transplanted into foam-plugged holes in polystyrene sheets floating on continuously aerated solution in each of four tubs. Four treatments were as follow; Control (2.32 d S m -1 ), 7.5 d S m -1, 15.0 d S m -1 and * University of Arid Agriculture, Rawalpindi Pakistan. ** University of Agriculture, Faisalabad Pakistan. *** Soil Fertility Survey and Soil testing Institute, Rawalpindi Pakistan. **** Soil Fertility Survey and Soil testing Institute, Lahore Pakistan.

2 Muhammad Islam, et al. Salt tolerance among different sunflower genotypes d S m -1. Nine sunflower genotypes, SF-177, SF- 187, GIMSUN-342, GIMSUN-459, GIMSUN-477, GIMSUN-686, GIMSUN-856, CRN-1435 and SH were tested for salinity tolerance. On the third day of transplantation, salinity was developed artificially with commercial NaCl. In order to raise the EC to 7.5, 15 and 22.5 d S m -1, the amount of NaCl required to be dissolved was 3.234, and g L -1, respectively. The ph of each tub was adjusted daily in the range of with the help of NaOH or HCl. The solutions were refreshed at 10 days interval during the entire experimental period. Plants were harvested after 30 days of transplantation. Growth parameters like root length, shoot length and number of leaves were recorded. Two fully expanded young leaves from each plant were collected and stored in eppendorf tubes at freezing temperature. Leaf samples in eppendorf tubes were thawed. After washing with distilled water, the tissue sap was extracted by pressing plant material with metal rod and sucking the sap with the help of micro pipette. The sap was stored in 1.5 cm 3 eppendorf tubes at freezing temperature. Before analysis, sap was stirred in Fisons Whirl mixer for at least two minutes. The stirred leaf sap was centrifuged in Clandon T 53 centrifuge machine at 6500 rpm for five minutes. The supernatant leaf sap was collected in another eppendorf tube and diluted as required for analysis of Na +, K + and Cl -. Sodium and potassium were determined by using Jenway flame photometer, while chloride was determined by using Sherwood 926 chloride analyzer directly calibrated in mg L -1 (Gorham et al. 1984). Data from the experiment was subjected to statistical analysis by using Randomized Design with factorial classification (Steel and Torrie, 1980) using MSTATC software. Treatment means were compared by LSD test. Composition of the Hoagland s nutrient solution used was as under: RESULTS AND DISCUSSION Effect of salinity levels on shoot length of sunflower genotypes Effect of salt stress on shoot length of individual sunflower genotypes is shown in table II. On overall mean basis, shoot length of all genotypes significantly decreased with increasing salinity. Genotype SF-177 had significantly higher shoot length (36.02 cm) at all salinity levels followed by GIMSUN- 686(34.47 cm) and GIMSUN- 856 (29.77 cm) while CRN-1435 had lowest (16.42 cm). These results are in good agreement with those of Francois (1996) and Ghumman (2000) in sunflower. The shoot length reduction under saline conditions could be attributed to toxicity of Na + and Cl - because of their higher concentration in medium (Bernal et al. 1974). At 75 mol m -3 salinity level, maximum shoot length (41.82 cm) was observed in GIMSUN-686 followed by SF-177 (38.32 cm) and GIMSUN-856 (36.42 cm) in a descending order. GIMSUN-686 significantly differed with GIMSUN- 856, while SF-177 and GIMSUN-856 differed non-significantly. The minimum shoot length was found in SH-3322 (18.4 cm) followed by CRN-1435 (23.5 cm) and GIMSUN- 342 (31.0 cm) in an ascending order. These genotypes differed significantly with each other. At 150 mol m -3 salinity, the maximum shoot length (33.12 cm) was recorded for SF-177 followed by GIMSUN-686 (30.62 cm) and GIMSUN-477 (24.62cm) in a descending order. The minimum shoot length (11.62 cm) was recorded for CRN-1435 followed by SH-3322 (15.7 cm) and SF-187 (19.9 cm) in an ascending order. There was significant difference between genotypes having maximum and minimum shoot length. At the maximum salinity of 225 mol m -3, shoot length in descending order was 28.82, and cm for SF-177, GIMSUN-686 and GIMSUN-856, respectively. Genotype SF-177 had significantly higher shoot length than all other genotypes. GIMSUN-856 and GIMSUN-686 differed nonsignificantly. The minimum shoot length values were observed in CRN (0.022), SH-3322 (13.9 cm), GIMSUN-342 (14.3 cm) and GIMSUN-459 (15.6 cm) in an ascending order. Genotype CRN differed significantly with all other genotypes. Possible reasons for reduction in shoot length may be that excessive accumulation of salts in cell wall modifies the metabolic pathways, reduces the cell wall elasticity and ultimately the shoot length. Further, secondary cell appears sooner and cell wall becomes rigid. As a consequence turgor pressure efficiency in cell enlargement declines. These processes may cause the shoot to remain smaller (Aslam et al. 1993). Effect of salinity levels on root length of sunflower genotypes The data presented in Table III depicts root length of different sunflower genotypes at different levels of salinity. On overall basis root length of all the genotypes decreased significantly with increasing salinity levels. Genotype SF-187 had maximum (43.75 cm) root length followed by GIMSUN-686 (37.02 cm) and GIMSUN- 459 (36.52 cm).

3 Sarhad J. Agric. Vol.24, No.2, At 75 mol m -3 NaCl salinity stress, the maximum root length was recorded for GIMSUN-686 (56.62 cm) followed by SF-187 (49.42 cm) and SF-177 (40.62 cm) in a descending order. The minimum root length was recorded for CRN-1435 (29.62 cm) followed by SH-3322 (31.92 cm) and GIMSUN-856 (34.02 cm) in ascending order. There was significant variation among these genotypes. At 150 mol m -3 salinity stress, the maximum root length (42.8 cm) was observed in SF-187, while GIMSUN-342 (33.8 cm) and GIMSUN-856 (33.9 cm) were at par with one another. The minimum root length was recorded in CRN-1435 (21.5 cm) followed by SH-3322 (29.4 cm) and GIMSUN-477 (30.4 cm). Genotypes SH-3322 and GIMSUN-477 were non-significantly different to one another. At 225 mol m -3 salinity, the maximum root length (33.4 cm) was observed for GIMSUN-856 followed by SF- 187 (32.8 cm) and GIMSUN-342 (29.3 cm) in descending order. The results matched to the findings of Ghumman (2000). Reduction in root length in response to salinity may be due to Na + and Cl - in the nutrient solution. High concentration of Na + and Cl - affects root permeability and integrity due to the displacement of Ca 2+ from the plasmalemma, which inhibits root growth and root length (Azaizeh and Stendele, 1991). Another reason might be that the salinity reduced the cell enlargement and cell division (Nieman, 1965). Effect of salinity levels on number of leaves of sunflower genotypes Data about number of leaves of different sunflower genotypes at different levels of salinity along with the control are presented in Table IV. It is clearly depicted from the data that number of leaves of all the genotypes decreased significantly with increasing salinity level. At 75 mol m -3 salinity, the maximum number of leaves (15.5) was observed in SF-187 followed by GIMSUN-686 (13.4) and GIMSUN-856 (13.0). The genotypes CRN-1435, SH-3322 and GIMSUN-477 had minimum number of leaves in the order of 10.4, 10.7 and 11.2, respectively and differed nonsignificantly with one another. At 150 mol m -3 salt stress, the genotypes with maximum number of leaves were SF-177 (10.9), SF- 187 (10.3) and SH-3322 (9.8) in descending order. There was non significant difference between means of three genotypes. Minimum numbers of leaves (7.02) were recorded for both GIMSUN-459 and CRN At maximum NaCl salinity of 225 mol m -3, the genotypes with maximum number of leaves were SH (7.6), SF-187 (7.3) and SF-177 (6.7). The genotypes with minimum number of leaves in an ascending order were CRN-1435 (1.02), GIMSUN- 342 (5.0), GIMSUN-477 (5.8) and GIMSUN-459 (6.0). Genotype CRN-1435 differed significantly with all other genotypes. These results are in confirmation with those of Nawaz et al. (2002) in sunflower. The reduced number of leaves with increasing salinity might be attributed to toxic effects of Na + and Cl - concentration in physiologically active part of tissue due to inefficient compartmentation of these ions in vacuoles (Yeo and Flower, 1986). This caused reduction in number of leaves as salts hinder the development of primordia, which determine the number of leaves of stressed plants (Grieve et al. 1993). Nutrition imbalance might be another reason for reduced number of leaves in general. Effect of salinity levels on sodium concentration of sunflower genotypes It is evident from the data that Na + concentration significantly increased with increasing salinity (Table V). On overall basis, minimum Na + concentration (52.8 mol m -3 ) was found in SF-177 while maximum Na + concentration was recorded in CRN-1435 (93.8 mol m -3 ). At 75 mol m -3 salinity stress, the maximum Na + concentration (45.8 mol m -3 ) was observed in GIMSUN-856. It was followed by GIMSUN-686 (43.5 mol m -3 ) and CRN-1435 (41.8 mol m -3 ). GIMSUM-856 had significantly higher Na + concentration than those of GIMSUN-686 and CRN Genotypes CRN-1435 and GIMSUN-686 were found to be mutually non-significant. At 150 mol m -3, the genotypes CRN-1435 had the maximum Na + concentration (111.1 mol m -3 ) followed by GIMSUN-459 (100.6 mol m -3 ) and GIMSUN-342 (96.8 mol m -3 ). The minimum Na + concentration of 65.5, 66.0 and 87.7 mol m -3, was found in SF-177, SF-187 and SH-3322, respectively in ascending order. Genotype SH-3322 was different significantly to those of mutually non-significant genotypes of SF-177 and SF-187. At 225 mol m -3, maximum Na + concentration (210.5 mol m -3 ) was recorded in CRN-1435, followed by SH-3322 (181.8 mol m -3 ) and GIMSUN-459 (175.7 mol m -3 ). Significant differences were found among all the three genotypes. The minimum Na + concentration (107.0 mol m -3 ) was found in SF-187 followed by SF-177 (110.4 mol m -3 ) and GIMSUN- 477 (126.1 mol m -3 ). Increase in Na + concentration

4 Muhammad Islam, et al. Salt tolerance among different sunflower genotypes 244 with increase in salinity was also reported earlier, e.g. in sunflower by Nawaz et al. (2002) and in wheat by Naseem et al. (2000). Exclusion of Na + at leaf or cellular level is an important salt tolerance mechanism in sunflower (Ashraf and Noor, 1993) and in wheat (Rashid et al. 1999). Tolerant crop plants maintain less Na + concentration in leaves at high stress level and plant maintain this low leaf Na + concentration mainly by efficient exclusion of Na + both from root and leaf. Gorham et al. (1986) reported that amphiploid tolerated salt stress better than wheat due to efficient exclusion of Na + and Cl - from the younger leaves. Effect of salinity levels on chloride concentration of sunflower genotypes (mol m -3 ) The Cl - concentration significantly increased with increasing salinity levels (Table IV). Means for Cl - concentration differed significantly at all the salinity levels. At 75 mol m -3 salinity stress, minimum Cl - concentration was observed in GIMSUN-856 (38.0 mol m -3 ), SF-187 (39.2 mol m -3 ) and SF-177 (39.5 mol m -3 ), while maximum in CRN-1435 (82.3 mol m - 3 ), GIMSUN-459 (75.6 mol m -3 ) and SH-3322 (70.2 mol m -3 ). The genotypes of minimum Cl - concentration differed non-significantly, while those of maximum were found to be differing significantly. At 150 mol m -3 salinity stress, minimum Cl - concentration was recorded for SF-177 (85.1 mol m - 3 ), SH-3322 (87.8 mol m -3 ) and SF-187 (89.9 mol m - 3 ), while maximum for GIMSUN-459 (111.5 mol m - 3 ), GIMSUN-342 (107.4 mol m -1 ) and GFIMSUN- 686 (106.4 mol m -3 ). In case of minimum Cl - concentration, genotype SF- 177 differed significantly from mutual non-significant genotypes of SF- 187 and SH In case of maximum concentration, GIMSUN-342 and GIMSUN-686 were at par. GIMSUM-459 had significantly higher concentration than those of GIMSUN-342 and GIMSUN-686. At 225 mol m -3 stress, the minimum Cl - concentration of 130.0, and mol m -3 was recorded in GIMSUN-856, SF-187 and SF-177, respectively. Genotype SF-177 significantly differed to other two genotypes. The maximum Cl - concentration of 176.7, and mol m -3 was observed in GIMSUN- 459, GIMSUN-686 and GIMSUN-342, respectively. There was significant variation among these three genotypes. Genotype GIMSUN-459 differed significantly from two other mutually non significant genotypes. Increased Cl - concentration with increased NaCl salinity matched with the results of Ashraf and Sultana (2000) in sunflower, Akhtar et al. (2002) and Rajper et al. (2002) in wheat and Ali et al. (2002) in cotton. Genotypes that could exclude both Na + and Cl - efficiently, particularly from younger leaves, are expected to be more tolerant than those, which could exclude either Na + or Cl - only (Rashid et al. 1999). Effect of salinity levels on potassium concentration of sunflower genotypes On overall basis, K + concentration decreased with increasing salinity level. (Table VII). Differences among genotypes were also significant. At 75 mol m - 3 stress, minimum K + concentration was found in CRN-1435 (129.4 mol m -3 ), GIMSUN-686 (134.0 mol m -3 ) and GIMSUN-342 (136.1 mol m -3 ). These genotypes differed non-significantly to each other. The maximum K + concentration was recorded for GIMSUN-459 (176.2 mol m -3 ), GIMSUN-856 (171.7 mol m -3 ) and GIMSUN-477 (161.7 mol m -3 ).. GIMSUN-459 and GIMSUN-477 were significantly different to one another while both were non significantly different to that of GIMSUN-856. At 150 mol m -3, the genotypes with minimum K + concentration were in the order of CRN-1435 (85.0 mol m -3 ), SH-3322 (88.5 mol m -3 ) and GIMSUN-686 (94.8 mol m -3 ) in ascending order. Non-significant variation among these genotypes was observed. The genotypes with maximum K + concentration were in the order of SF-187 (148.5 mol m -3 ), GIMSUN-856 (148.2 mol m -3 ), and SF-177 (132.9 mol m -3 ) in descending order. SF-187 and GIMSUN-856 were non-significantly different to one another while both were significantly different to that of SF-177. At 225 mol m -3 salinity stress, minimum K + concentration was observed in CRN-1435, GIMSUN- 686 and GIMSUN-477 as 65.0, 66.9 and 82.3 mol m - 3, respectively. GIMSUN-477 was found to have significantly higher K + concentration than those of other two genotypes. Genotypes CRN-1435 and GIMSUN-686 non-significantly differed to one another. Genotypes with maximum K + concentration were GIMSUN-856, SF-187 and SF-177. Their K + concentration was 124.7, and mol m -3, respectively. These genotypes non-significantly varied to one another. Decreased K + concentration with increased salinity was also reported earlier by Ashraf and Sultana (2000) and Nawaz et al. (2002) in sunflower and Akhtar et al. (2002) and Iqbal et al. (2002) in wheat. Decreased K + concentration could be attributed to high external Na + concentration, which inhibited K + absorption. Also high Na + concentration displaced Ca 2+ from the plasmalemma resulting in loss of membrane integrity and efflux of cytosolic K +, hence K + concentration in leaves decreased (Cramer et al. 1985; Kent and Lauchli, 1985). This increased maintenance of K + at high

5 Sarhad J. Agric. Vol.24, No.2, external NaCl by glycophytes could be the genotypic characteristics of plants (Benes et al. 1996). Effect of salinity levels on K + : Na + of sunflower genotypes On overall basis, K + : Na + ratio decreased significantly with increased salinity as compared to control (Table VIII). Genotypes also differed significantly for K + : Na + ratio at all the salinity levels. At 75 mol m -3 NaCl salinity, maximum K + : Na + ratio (5.32) was found in SF-187, followed GIMSUN- 477 (5.12) and SH (4.22). All the three genotypes differed non-significantly. The minimum K + : Na + ratio (3.2) was observed in GIMSUN-686 and CRN- 1435, while SF-177 (3.3) and GIMSUN-459 (3.5) were second and third in this category, respectively. All these genotypes differed non-significantly to one other. At 150 mol m -3 NaCl stress, the genotypes having maximum K + : Na + ratio could be arranged in descending order as, SF-187 (2.3), SF-177 (2.1), and GIMSUN-856 (1.7). Non-significant variation was observed in these genotypes. The genotypes showing relatively lower K + : Na + ratio could be arranged as CRN-1435 (0.8), GIMSUN-686 (1.1) and GIMSUN- 342 (1.3) and GIMSUN- 459 (1.3). All these genotypes differed non-significantly to one another. At 225 mol m -3 NaCl stress, the genotypes SF-187 (1.1), SF-177 (1.0), GIMSUN-856 (0.82) could be sorted out as having maximum K + : Na + ratio. These genotypes differed non-significantly. The lowest K + : Na + ratio (0.3) was recorded for CRN It was followed by GIMSUN-686 (0.4) and GIMSUN-459 (0.5). These results are in good agreement with those of Naseem et al. (2000) and Nawaz et al. (2002) in sunflower and Akhtar et al. (2002), and Rajper et al. (2002) in wheat. Decreased K + : Na + ratio with increased salinity was due to displacement of Ca 2+ from plasmalemma at high external Na + concentration (Cramer et al. 1985). This K + leakage from the cell lowers the K + : Na + ratio in the tissue (Kent and Lauchli, 1985). At salinity 150 and 225 mol m -3, genotypes SF-187, SF-177 and GIMSUN- 856 have high K + : Na + ratio indicating high K + : Na + selectivity, an important mechanism of salt tolerance (Parakash et al. 1996). The K + : Na + ratio for nonhalophytes should, in general, be > 1 for normal functioning of all the metabolic processes in the plants (Why Jones et al. 1979). CONCLUSION Among nine genotypes tested for their salt tolerance, SF- 177 and SF- 187 showed good growth because of better mechanism for Na + exclusion. These genotypes + maintained lower Na and Cl - and higher K + concentration, thus resulting in higher K + : Na +. Genotypes CRN was most sensitive to salt stress. It had poor mechanism for K + : Na + selectivity resulting in higher concentration of Na + and lower concentration of K +. Other genotypes were intermediate in behavior. Table I Composition of the Hoagland s nutrient solution Reagent Stock g L -1 ml. Stock Solution for 200 L Hoagland Solution x (1/2) Strength KH 2 PO KNO Ca(NO 3 ) 2.4H 2 O MgSO 4.7H 2 O Micronutrients H 3 BO MnCl 2. 4H 2 O 1.81 ZnSO 4.7H 2 O 0.22 CuSO 4. 5H 2 O 0.08 H 2 MoO 4.H 2 O 0.02 Fe EDTA

6 Muhammad Islam, et al. Salt tolerance among different sunflower genotypes 246 Table II Effect of salinity levels on shoot length of sunflower genotypes (cm) Genotypes control 75 mol m mol m mol m-3 Mean SF ab d g i a SF a ef mn p cd GIMSUN fg h lm p f GIMSUN bc def lm p de GIMSUN ef ef j o e GIMSUN a bc hi lm b GIMSUN c de kl mno c CRN hi jk q q h SH jk no p p g Mean a b c d Table III Effect of salinity levels on root length of sunflower genotypes (cm) Genotypes control 75 mol m mol m mol m-3 Mean SF ijkl def j-m pq e SF b bc de i-m a GIMSUN d fg i-l opq c GIMSUN c ef k-o pq bc GIMSUN gh fg m-p qr e GIMSUN hi a l-o r b GIMSUN def ijk i-l ijkl d CRN hij n-q s 0.02 t g SH fg k-o opq r f Mean 40.0 a 40.0 a b c Table IV Effect of salinity levels on number of leaves of sunflower genotypes Genotypes control 75 mol m mol m mol m-3 Mean SF cd d ef 6.72 k ef SF a a f 7.32 j d GIMSUN c cd 8.42 j 5.02 lm fg GIMSUN a e 7.02 jk 6.02 kl fg GIMSUN bc ef 7.32 j 5.82 kl 9.54 g GIMSUN a c 8.02 hi 6.22 kl ef GIMSUN bc cd 9.32 g 7.32 j ef CRN cd f 7.02 jk 1.02 n 7.82 hi SH ef f 9.82 fg 7.62 j 9.80 fg Mean a b 8.69 c 6.33 d

7 Sarhad J. Agric. Vol.24, No.2, Table V Effect of salinity levels on sodium concentration of sunflower genotypes (mol m -3 ) Genotypes control 75 mol m mol m mol m -3 Mean SF yz 33.92r n h h SF z s n i i GIMSUN xy q k d d GIMSUN wx p j c b GIMSUN uv rs m g g GIMSUN t p l e e GIMSUN u o l f f CRN vw p h a a SH wx q m b c Mean 11.54d c b a Table VI Effect of salinity levels on chloride concentration of sunflower genotypes (mol m -3 ) Genotypes control 75 mol m mol m mol m -3 Mean SF x s l e e SF y s k f e GIMSUN w 68.0 o h b c GIMSUN vw n g a a GIMSUN uv 56.7 p j d d GIMSUN r q h b c GIMSUN y 38.0 st 95.4 j f e CRN uv m i c b SH tu o k p f Mean d c b a Table VII Effect of salinity levels on potassium concentration of sunflower genotypes Genotypes control 75 mol m mol m mol m -3 Mean SF de hij jkl n c SF efg de fgh mn b GIMSUN bcde 136.1ijk lm o d GIMSUN abc ab klm o b GIMSUN cde de mn q e GIMSUN jkl jkl o p f GIMSUN a bcd fgh klm a CRN ghi jklm 85.0 o 65.0 p f SH bcd ef o 88.5 o d Mean 162.1a b c d

8 Muhammad Islam, et al. Salt tolerance among different sunflower genotypes 248 Table VIII Effect of salinity levels on K + : Na + of sunflower genotypes Genotypes control 75 mol m mol m mol m -3 Mean SF ab 3.32 f-j 2.12 g-m 1.02 j-m 6.58 ab SF a 5.32 f 2.32 g-m 1.12 i-m 7.80 a GIMSUN bc 3.52 f-j 1.32 i-m 0.62 klm 5.67 bc GIMSUN c 4.12 fgh 1.32 i-m 0.52 lm 5.52 bcd GIMSUN d 5.12 f 1.42 h-m 0.72 klm 4.89 cde GIMSUN e 3.22 f-l 1.12 i-m 0.42 m 3.54 e GIMSUN d 3.82 fghi 1.72 g-m 0.82 j-m 4.92 cd CRN d 3.22 f-l 0.82 j-m 0.32 m 4.24 de SH c 4.22 fg 1.42 h-m 0.52 lm 5.74 bc Mean a 3.98 b 1.51 c 0.68 c REFERENCES Akhtar, J., M. Saqib, R.H. Qureshi and M. Aslam Effect of salinity and sodicity on grain yield, different yield components and ionic relations of different wheat genotypes. 46p. In: Abst. 9 th Int, Congress of Soil Sci. March 18-20, 2002, NIAB, Faisalabad, Pakistan. Ali, A., B. Zaman and M. Salim Evaluation and performance of different commercial sunflower hybrids under saline conditions. 47p. In: Abst. 9 th Int, Congress of Soil Sci.. March 18-20, 2002, NIAB, Faisalabad, Pakistan. Ashraf, M. and R. Noor Growth and pattern of ion uptake in Eruca sativa Mill under salt stress. Ange. Bot. 67: Ashraf, M. and R. Sultana Combination effect of NaCl salinity and nitrogen form on mineral composition of sunflower plants. Biologia Plantarum. 43: Aslam, M., R.H. Qureshi and N. Ahmad Mechanisms of salinity tolerance in rice (Oryza sativa L.). pp In: Leith, H. and A.A. Massoum (eds.) Towards rational use of high salinity tolerant plants. Vo. 2. ASWAS Conf. Dec. 8-15, UAE. Kluwer Acad. Publ., Dordecht. Azaizeh, H. and E. Stendele Effect of salinity on water transport of excised maize root. Plant Physiol. 97: Benes, S. E., R. Aragues, S.R. Grattan and R.B. Austin Foliar and root adsorption of Na + and Cl - in maize and barley: Implications for salt tolerance screening and the use of saline sprinkler irrigation. Plant and Soil. 180: Bernal, C.T., F.I. Bingham and J. Dertli Salt tolerance of Mexican wheat. II. Relations to variable sodium chloride and length of growing season. Soil Sci. Soc. Amer. Proc. 38: Bohra, J.S. and K. Dörffling, Potassium nutrition of rice (Oryza sativa L.) varieties under NaCl salinity. Plant and Soil. 152: Botella, M.A., V. Martinez, J. Pardines and A. Cerda, Salinity induced potassium deficiency in maize plants. J. Plant Physiol. 150: Cramer, G.R., A. Lauchli and V. S. Polito Displacement of Ca 2+ by Na + from plasmalemma of root cells. A primary response to salt stress. Plant Physiol. 79: Francois, L.E Salinity effects on four sunflower hybrids. Agron. J. 88: Gadallah, M.A.A Effects of proline and glycinebetaine on Vicia faba responses to salt stress. Biologia Plantarum. 42: Ghumman, M. I Evaluation of S 2 sunflower (Helianthus annus L.) genotypes for salinity tolerance. M.Sc Thesis. Deptt. PBG, Univ. Agric. Faisalabad. Gorham, J., E. McDonnell and R.J. Wyne Jones Salt tolerance in Triticeae.I. Leymus Sabulasus. J. Exp. Bot. 35: Gorham, J., B. P. Forster, E. Budrewicz, R.G. Wyn Jones, T.E. Miler and C.N. Law Salt tolerance in the Triticeae: solute accumulation and distribution in an amphidiploid derived from (Triticum aestivum L.) cv. Chinese Spring and Thinopyrum bessarabicum. J. Exp. Bot. 37:

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10 Muhammad Islam, et al. Salt tolerance among different sunflower genotypes 250