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Pak. J. Bot., 40(4): 1657-1663, 2008. |
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Updated: 09-07-09 |
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ALLEVIATION OF ADVERSE EFFECTS OF SALT STRESS ON SUNFLOWER (HELIANTHUS ANNUUS L.) BY EXOGENOUS APPLICATION OF SALICYLIC ACID: GROWTH AND PHOTOSYNTHESIS
SIBGHA NOREEN AND *MUHAMMAD ASHRAF
Abstract: The present study was conducted to assess whether exogenously applied SA as a foliar spray could ameliorate the adverse effects of salt stress on sunflower plants. Two lines of sunflower (Hisun-33 and SF-187) were grown under normal or saline (120 mM NaCl) conditions. Different levels of salicylic acid (0, 100, 200, 300 mg L-1) were applied as a foliar spray. Salt stress reduced the growth of both lines, but both cultivars were equally responsive to the stress. Application of 200 mg L-1 of SA caused an increase in biomass of both lines under non-saline or saline conditions. Photosynthetic rate of both cultivars increased due to SA applied foliarly both under control and saline conditions, particularly in line SF-187. Furthermore, increase in growth of both cultivars due to exogenously applied SA may have been due to changes in photosynthesis. However, SA applied as a foliar spray did not change the sub-stomatal CO2 suggesting that stomtal factors were not the major controlling factors for photosynthesis. Overall, the adverse effects of salt stress could be alleviated by exogenous application of SA.
Department of Botany, University of Agriculture, Faisalabad 30840, Pakistan Corresponding author: ashrafbot@yahoo.com |
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