For sustainable space exploration there is need for torrential food supply. Apart from food in storage, constant production is vital as this could also serve as a source of Oxygen when activated during space expedition. However, the impact of gravity in crop development is significant. This study therefore, investigated the morphological and physiological responses of Maize (Zea mays) seedlings subjected to clinorotation. Agar Agar was used as source of nutrient for the developing seedlings. The Agar was prepared by measuring 1 -1.5 g and made up to 100 ml with tap water. Seeds were collected in the seed bank of the Space-Earth Environment Research Laboratory, Benin City. Three sets of petri dishes were prepared and marked; one for normal surface, one rotated at 90°C and another set for clinorotation. Those for clinorotation were rotated at three different times; with 1, 2, and 3 rpm for 6 hrs respectively. The plumule, radicle and Enzyme activities were measured and analysed after four days. Results showed significant difference in germination parameters as occasioned by microgravity. Where as clinorotation enhanced radicule length (1.8-2.1cm), effect on plumule was minimal (p>0.05). Significant increase in CAT activity in the plumule was reported (7.59mol/sec) in the clinorotated (1rpm) seed compared to the control (2.56mol/sec). MDA activity in both radicle and plumule were higher than that of the control (p<0.05). Microscopic study of the cells was carried out using a binocular microscope (Labo) with a camera and result showed that the normal surface sample cells were arranged concentrically with spaces, while that of clinorotated seeds were arranged concentrically but highly packed with little spaces for the plumule. For the radicle, the normal surface sample cells were scattered within the plant with more spaces, while that of clinorotated were mostly clustered throughout.

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.