Physical, chemical and biological characteristics of space flown tomato (Lycopersicum esculentum) seeds

Several research showed that space flown treated seeds had a different characteristic with that of ground treated seed, which eventually produced a different characteristic of growth and productivity. Research was conducted to study the physical, chemical and biological properties, such as the rate of germination and the growth of tomato (Lycopersicum esculentum) space flown seeds compared with that of control one. Observations of physical properties using a SEM showed that there were pores on the surface of some tomato space flown seeds. Observations using a stereo and inverted microscope showed that the coat layer of space flown seeds was thinner than control seeds. The total mineral content in the control seeds (22.88%) was averagely higher than space flown seeds (18.66%), but the average carbohydrate content in control seed was lower (15.2 ± 2.79%) than the space flown seeds (9.02 ± 1.87%). The level of auxin (IAA) of control seeds (142 ± 6.88 ppm) was averagely lower than the space flown seeds (414 ± 78.84 ppm), whereas the level of cytokinins (zeatin) for the control seeds (381 ± 68.86 ppm) was higher than the space flown seeds (68 ± 9.53 ppm), and the level of gibberellin (GA3) for the control seeds (335 ± 10.7 ppm) was higher than the space flown seeds (184 ± 7.4 ppm). The results of this study showed that the physical and chemical properties of tomato space flown seeds were generally different compare with that to control seeds, so that it might also be resulted in different germination and growth characteristic. The germination test showed that space flown seeds had lower germination rate compare to control. The growth pattern indicated that planted space flown seeds generally grew better than control. However, those data were more homogenous in control seeds compare to that in space flown tomato seeds.