Fig. 4.

Effect of plant hormones on H. maydis spore germination. To study the effect of phytohormones on colonies’ growth rate, the PDA medium was embedded with the different hormones to a final concentration of 100 mg/L. Plates were inoculated as described in Fig. 1. For the spore germination assay, spores were washed from the agar surface of 4-day-old colonies grown under the above conditions and suspended in watery solutions containing the various hormones described in Fig. 1. The spores’ suspensions in Eppendorf tubes were then incubated in a rotary shaker at 150 rpm at 28 ± 1 °C in the dark. a. The percentage of germinating conidia was determined after 0, 10, 13 and 16 h by direct counting of the spores with any visible germ tube emerging. The controls were spores in DDW without hormones and spores in DDW containing pre-boiled kinetin solution (named de-kinetin) at the same concentration (100 mg/L). Values represent the average of six replicates. Error bars indicate standard error. Asterisks represent significant (*P = 0.05, **P = 0.005, ***P < 5*10⁻⁴) differences from the control. b. Representative photograph of the hormones spore solutions at the time interval examined. Abbreviations as in Fig. 1