Alleviation of Allelopathic Effect of Launae sonchoids Weed on Wheat Growth by Salicylic Acid

EXPERIMENT for the study of alleviation of allelopathic effect of Launae sonchoids on wheat growth by pretreatment grains with salicylic acid (SA). Launae sonchoids was collected from the desert plains at Taif area, Saudia Arabia and sampled in March 2010. The germination and growth were conducted in the greenhouse during April 2010. Diluted extracts of Launae sonchoids shoot system was applied to pre-soaked in SA or non soaked wheat grains. The aqueous extract of Launae sonchoids at 25% caused an increase in the root and shoots growth and biomass production of the wheat seedlings at pre-soaked in SA or H₂O comparison with control. The concentrated extracts (75 and 100%) were phytotoxic to wheat germination. The percentage declined by pre-soaked wheat grains in 0.05 mM salicylic acid. Betaine levels in seedlings pretreated with salicylic acid significant increase versus untreated seedlings, possibly because such a precursor promotes betaine biosynthesis. This could be responsible for the enhanced growth criteria and preventing the decrease in chlorophyll content in the pretreated seedlings. A relationship between nitrogenous fractions, antioxidant glutathione and Launae sonchoids extract tolerance observed in wheat seedlings with or without salicylic acid. Overall, the adverse effects of allelopathic stress could be alleviated by pre-treated with SA.