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REGULATION IN GAS EXCHANGE AND QUANTUM YIELD OF PHOTOSYSTEM II (PSII) IN SALT-STRESSED AND NON-STRESSED WHEAT PLANTS RAISED FROM SEED TREATED WITH TRIACONTANOL

SHAGUFTA PERVEEN¹, MUHAMMAD SHAHBAZ^1* AND MUHAMMAD ASHRAF^1,2

Abstract: To assess the effect of exogenous application of triacontanol (TRIA) as a presowing seed treatment on wheat under saline conditions, a greenhouse experiment was performed. Seeds of two wheat cultivars, MH-97 (moderately salt sensitive) and S-24 (salt tolerant) were primed with TRIA for 12 h. Plants raised from TRIA-treated seeds were grown in full strength Hoagland’s nutrient solution for 24 days under non-saline conditions, after which time, they were subjected to 0 (control) or 150 mM NaCl. After 21 days of salt application, data for different growth, plant pigments and gas exchange characteristics were recorded. Salt stress of the root growing medium markedly decreased shoot and root fresh biomass, net CO₂ assimilation rate (A), stomatal conductance, and transpiration rate (E), while no significant effect of salinity was observed on chlorophyll pigments (a, b and a/b ratio), quantum yield of PSII, substomatal CO₂ concentration and water use efficiency (A/E). Exogenous application of TRIA as seed priming did not ameliorate the inauspicious effects of salt stress effectively, although it slightly increased photosynthetic rate in both wheat cultivars, transpiration rate in MH-97 and water use efficiency in S-24 under saline conditions.   

¹Department of Botany, University of Agriculture, Faisalabad, Pakistan

²Second Affiliation: King Saud University, Riyadh, Saudi Arabia