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The present investigation was conducted at the nurseryof Hort. Res. Inst., ARC, Giza, Egypt during 2013 and 2014 seasons tostudy the effect of different pre-sowing seed treatments, viz., untreatedseeds (control), soaking in tap water for 24 h at room temperature,soaking in previously boiling water for 24 h at room temperature,boil/cold water dipping (thermal shock treatment), soaking inconcentrated H2SO4 for either 2 or 4 min (chemical scarification) andabration testa with rough emery paper (mechanical scarification) onseed germination and seedling growth of Powder Puff (Calliandrahaematocephala Hassk.) shrub.The obtained results indicated that most of the used treatmentsimproved germination % and velocity, mean germination rate,germination rate and vigour indices, seed viability and epicotyl lengthof germinated seeds, as well as seedling growth with varioussignificant differences compared to control in the two seasons, exceptfor thermal shock treatment which completely failed to inducegermination. It was also noticed that seed viability markedly decreasedas a result of mechanical scarification with emery paper to reach theleast values at all. Content of total indoles and phenols in the untreatedseeds was stable as they were not subjected to any treatment, but intreated seeds, it was increased where total indoles reached themaximum by soaking in either concentrated H2SO4 or boiling water,while these two treatments caused a nil increment in seed content oftotal phenols relative to control and other pre-sowing treatments. Inaddition, content of chlorophyll a, b, carotenoids and total solublesugars in the leaves of seedlings raised from the treated seeds wasgreatly increased, especially by chemical and thermal scarification.Generally, the mastery in all previous measurements was for soakingin either concentrated H2SO4 for only 2 min or boiling water for 24 h,as they recorded the utmost high means in the majority of measuredtraits in both seasons.Hence, it is recommended to treat seeds of Calliandrahaematocephala pre-sowing by soaking in either previously boilingwater for 24 h. or in concentrated H2SO4 for only 2 min. to obtain thebest germination and seedling growth.