Effects of Selected Plant Growth Stimulators on 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, with strong predictions that its carrying capacity could be overstretched soon. 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, it is important to evaluate the extents by which plant growth stimulators can reverse or enhance this trend. A total of ۱۲ maize seeds were weighed and placed sideways in petri dishes and inoculated with plant growth stimulators, indole acetic acid (IAA), gibberellic acid (GA), and ascorbate (AA). They were clinorotated at different rates (۰.۵, ۱.۰, and ۲.۰ rpm), while the control seeds were just placed on a balanced table. Results of this research showed that under microgravity, the maize seeds had a decreased level of germination percentage with increasing clinorotation rates at ۷۲ hrs, compared to the control group. But when stimulated with IAA, GA and AA, they improved in germination percentage, compared to the control, even under microgravity conditions. 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 micro-gravitational impact. However, IAA caused more improvements in seedling vigor, compared to the other growth regulators, while GA had more effects on the rate of germination. This research confirmed the possibilities of improving germinability in maize seeds under space exploration conditions.

Keywords:

Clinostat , Microgravity , Zea mays , indole acetic acid , gibberellic acid , Ascorbic acid