Influence of selected plant growth stimulators in enhancing germinability and germination parameters of Zea mays L. under microgravity conditions simulated by a two-dimensional clinostat

The earth has become increasingly overcrowded as a result of rapid urbanization and population growth, predicting that its carrying capacity could be overstretched. As a result, it is important to test the possibilities of growing plants under space exploration conditions, especially gravitational balance. Since microgravity impedes plant development, to what extent can plant growth stimulators reverse or enhance this trend? A total of 12 maize seeds were weighed and placed sideways in petri dish and inoculated with plant growth stimulators such as indole acetic acid (IAA), gibberellic acid (GA), and ascorbate (AA) and the clinorotated at different rates (0.5, 1.0 and 2.0 rpm), while control seeds were just placed on a table. Results showed that at 72 hrs, the maize seeds under microgravity showed reduced germination percentage with increasing clinorotation rates as against the control. But when stimulated with IAA, GA and AA, improved germination percentage was observed as against the control even under microgravity condition. The seedling dry weight, germination time and other germination parameters also showed similar improvements. Comparatively, the three growth stimulators showed no major variations in their ability to improve germination percentage under microgravitational impact. However, IAA showed more improvement on seedling vigor as against others, while GA showed more effect on the peak time and rate of germination. This research confirmed the possibilities of improving germinability of maize seeds under space exploration condition.