Fig. 1

Effects of different concentrations of Hx, DPD and N-MMP on the endogenous heme content and morphology of cucumber seedlings. A Endogenous heme content of cucumber seedlings under different concentrations of Hx. B Endogenous heme content of cucumber seedlings under different concentrations of DPD. C Endogenous heme content of cucumber seedlings under different concentrations of N-MMP. D Photos of plant morphology selected by Hx concentration. E Photographs of plant morphology screened by DPD concentration. F Photographs of plant morphology screened by N-MMP concentration. Values were mean ± SE (n = 3). Bars with different lowercase letters were significantly different by Tukey’s multiple range test (P < 0.05)