2.5 Statistical analysis
Data obtained were tested by analysis of variance (ANOVA). For the comparison of means, Tukey’s test was applied at 5% significance, using the software AgroEstat (Barbosa and Maldonado Júnior, 2009) and RStudio (Solanki et al. 2017).
Germination Percentage (G%) was determined by G% =\(\frac{\sum_{\text{ni}}}{N}.100\), where \(\sum\)ni is the total number of germinated seeds and N is the total number of seeds tested (Labouriau, 1983). The Average Germination Speed was determined according to the expression AGS = \(\frac{\text{ni}\ }{\text{ti}}\ \), in which “ni” is the number of seeds germinated at time “i” and “ti” is the time after implementation of the test (Carvalho and Carvalho, 2009). The Germination Speed Index (GSI) was determined with the expression GSI =\(\frac{G_{1}}{N_{1}}+\frac{G_{2}}{N_{2}}\ldots+\frac{G_{n}}{N_{n}},\)where G1, G2, …Gnrefer to the number of germinated seeds and N1, N2, Nn, to the number of days after sowing (Maguire, 1962).
Results
The use of the filter paper saturated with deionized water in Petri dishes or the in vitro germination using culture media containing phytorregulators resulted in a successful and rapid cultivation system for observing and quantifying the germination of Melocactusseeds. Germination of M. zenhtneri seeds began with the protrusion of the hypocotyl-radicle axis, as the result of the growth and enlargement of the embryo, which leads to the seed coat disruption (Fig. 2).