Water culture experiments were conducted to study the response of ten wheat genotypes to external K application (10 mmol KCI dm _ 3 ) at seedling stage under saline condition (0 and 100 mmol NaCl dm _ 3 ). The data showed that there was an increase in the shoot and root length with the application of external K. The increase was more pronounced under control than under saline conditions. The better performing genotypes under two treatments were Bhitai, NIAB-41, NIAB-I076 and Khirman. The enhanced growth of these genotypes under saline condition might be due to the quick response to external K application, resulting in high K/Na ratio. The results indicated that the genotypes, which have the ability of enhanced K/Na discrimination, might perform better under saline conditions when sufficient potassium is applied in the rooting medium.

In Pakistan most of the salt affected areas are located in the heart of its agriculturally important tract of the Indus plain. Growing conventional crops in these problem lands is not economical but these could be utilized gainfully by growing salt tolerant trees or shrubs. However, there is a need to identify suitable species for such conditions. The present study was, therefore, undertaken to evaluate the performance of some local and exotic trees, belonging to Acacia species, in salt affected soils of Pakistan. Five species of Acacia, i.e., Acacia ampliceps, A. stenophylla, A. machonochieana, A.sclerosperma, and A.nilotica were grown along with an Australian halophytic shrub Atriplex lentiformis in a field where salinity ranged from 4-25 dS m -1 . After three years of growth, A. ampliceps and A. nilotica showed markedly higher growth as compared with the other species examined. Although A. ampliceps grew well under saline environment, its maximum growth was observed under -1 (12--1 medium to high salinity levels (8-16 dS m -1 ), while Acacia sclerosperma and A. machanochieana were only populated on low salinity patches (4-8 dS m -1 ). Analysis of plant leaves, for nutrient contents, showed that the concentrations of Na + and K + ions in the Acacia species were comparatively less than those in Atriplex lentiformis. However, Acacia nilotica had comparatively higher nitrogen and phosphorus than the other Acacia species examined. On the other hand, the concentrations of Na + and K + were higher in Atriplex lentformis while the concentrations of Ca 2+ were higher in Acacia sclerosperma as compared to the other Acacia species and Atriplex. At the end of the experiment, complete soil analysis was carried out which showed that the soils on which Acacia species were grown, N, P, and K contents increased to some extent.

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