*Means followed by different letters were significantly different by Tukey’s Test at 5% probability

Fig. 1 . Adult plant of M. zehntneri with cephalium (left) and details of cephalium containing mature fruit (right) used to collect seeds for the experimental procedures. Original photos of JCC and MFCM

Fig. 2 . Germination of seeds and color of seedlings ofMelocactus zehntneri under different wavelengths: Red (V); Blue (A); Red and Blue (V+A) and; White (B).

Fig. 3. Germination (%) of seeds of Melocactus zehntneri cultivated under different wavelengths and PPFDs source by LEDs: Percentage of seed germination (A) (Different lowercase letters in the same column indicate the effects of the wavelength and uppercase letters indicate the effects of PPFDs on germination. Shapiro-Wilk Normality Test = 0.36, Levene Test for Homoscedasticity = 0.71. Coefficient of Variation = 13.2%. F-values for: wavelengths (10.81**), PPFDs (4.86*), and Interaction (1.67 ns). Significant at 5%(*) and 1%(**) probability. ns, non-significant); speed germination index (GSI) (Shapiro-Wilk Normality Test = 0.50, Levene Test for Homoscedasticity = 0.68. Coefficient of Variation = 24.95%. F-values for: wavelengths (12.87**), PPFDs (4.42*), and Interaction (2.05 ns). Significant at 5%(*) and 1%(**) probability. Ns, non-significant); correlation between percentage of seed germination and light PPFD (C) and speed germination average under different LEDs wavelengths (D).

Fig. 4 . Germination percentage of seeds of Melocactus zenhtnerii subjected to pre-treatment with Ethephon and to different phytoregulators in the culture medium. Shapiro-Wilk Normality Test = 0.857; Levene Test of Homoscedasticity = 0.7278. Coefficient of Variation = 32.7%. F-values for phytoregulators (1.58 ns), ethephon (11.37**), and Interaction (0.82 ns). Significant at 5%(*) and 1%(**) probability. Ns, non-significant.

Fig. 5 . Average germination speed (AGS) of Melocactus zehntneri seeds cultivated under different wavelengths (Blue, Deep red, Red and Blue, White) sourced by LEDs and photosynthetically photon flux densities (PPFDs)

Fig. 6 – Germination Speed Index (GSI) of M. zenhtineriseeds subjected to different phytoregulators added to the culture media and pre-treatment with Ethephon. Shapiro-Wilk Normality Test = 0.63; Levene Test of Homoscedasticity = 0.0975. Coefficient of Variation = 28.3%. F-values for phytoregulators (2.75 ns), Ethephon (9.98**), and Interaction (0.49 ns). Significant at 5%(*) and 1%(**) probability. ns, non-significant.