THE EFFECTS OF IAA, SNP AND THIOUREA GROWTH STIMULATORS ON CHEMOPRIMED BEAN SEEDS PRESENT IN MICROGRAVITY USING A 2D CLINOSTAT

Research into the effects of microgravity on plants has increased significantly because of its importance to long-duration space missions and the possibility of cultivating food crops in extraterrestrial environments. This study examined the effects of Indole-3-Acetic Acid (IAA), Thiourea (T. urea), and Sodium Nitroprusside (SNP) on chemoprimed bean seeds exposed to simulated microgravity using a two-dimensional (2D) clinostat. The seeds were divided into a control group treated with water and experimental groups treated with IAA, Thiourea, or SNP at concentrations of 500 ppm and 1000 ppm. Following treatment, the seeds were maintained under either simulated microgravity using the 2D clinostat or normal gravity conditions. Germination percentage, root and shoot lengths, root number, fresh weight, dry weight, and other observable growth characteristics were evaluated. The results showed that all treatment groups recorded high final germination percentages, although their responses varied according to the growth stimulant, concentration, and gravity condition. SNP at 500 ppm gave the most favorable results, producing the quickest germination, highest germination index, and strongest seedling vigour under both gravity conditions. IAA at 500 ppm promoted early germination and improved seedling establishment, whereas the 1000 ppm treatment generally reduced growth, indicating that higher IAA concentrations may have inhibitory effects. Thiourea enhanced germination uniformity and root development, while the 1000 ppm treatment supported vigorous seedling growth under simulated microgravity. Overall, the study demonstrates that IAA, Thiourea, and SNP may enhance crop establishment under controlled conditions and could be useful in the development of agricultural systems for future space exploration. Among the treatments tested, SNP at 500 ppm exhibited the most consistent and effective overall performance.