“…A pharmacological approach was adopted to investigate whether changes in the endogenous levels of key regulators of seed germination such as the phytohormones such as ABA, GA and ethylene, as well as ascorbic acid (AA) or hydrogen peroxide (H 2 O 2 ), were involved in the control of the thermoinhibition process. When indicated, seed germination (three plates with 30–35 seeds each) was performed at HT (33°C), in the darkness, in the presence of different concentrations of the ABA biosynthesis inhibitor fluridone, ethephon (acid 2-chlorethylphosphate), which is a source of ethylene in plant tissues (Kolářová et al, 2010 and references therein), GA 4+7 , GA 3 (supplied either alone or in combination with fluridone or ethephon), AA or H 2 O 2 . When indicated, the GA biosynthesis inhibitor paclobutrazol (Hedden and Graebe, 1985) was included in ethephon treatments (see Table 2 for a description of all the conditions tested).…”