Comparative Study on Effect of Salinity on Seed Germination and Seedling Growth of Different Linum Usitatissimum Varieties

Salinity stress gives serious negative impact on plant growth and development and reduces yield and productivity of plants. In world, increase demand of food with increase in salinity worldwide results in cultivation of salt tolerant varieties to fulfill food demand from salt affected areas. For this purpose, present study was conducted with the aim to screen four lines of Linum usitatissimum (i.e; Alsi Ari 1, Alsi Ari 20, Alsi Ari 22 and Alsi Ari 50) for salt tolerance in terms of germination and seedling growth. Experiment was completely randomized, replicated thrice and conducted at Plant Physiology Laboratory, Department of Botany, Abdul Wali Khan University Mardan. Five seeds of four varieties of Linum usitatissimum were placed in each Petri plate. Seeds treated with different concentrations (0, 50mM and 150mM) of NaCl. After 8 days, experiment was terminated and germination percentage, seedling length, seedlings biomass were recorded, while relative water content, vigor index, RSR, SWR, RWR and stress tolerance index of different parameters were calculated. Analyzing the results, outcome confirmed that salt stress damage the plant at observed stages in the form of drastic and significant reduction in germination percentage, shoot length, root length, fresh weight, dry weight, relative water content, vigor index, PHSI, RLSI, SFTI, RFTI, SDTI, RDTI, SWR and RWR while RSR increased in different varieties. Reduction percentages of different parameters were increased as salt stress level increased in all studied varieties. On the basis of results obtained using above mentioned physiological criteria, among four lines, Alsi ARI 1 showed higher salt tolerance at germination and seedling growth stage as compare to the other lines. Results of present investigation, different physiological parameters of this study are useful to screen different flax lines for salt tolerance, leading to selection of suitable line, recommended for different saline areas to