Growth and Anatomical Responses of Lycopersicon esculentum (Tomatoes) under Microgravity and Normal Gravity Conditions
Microgravity is known to be a major abiotic stress in space which affects plants depending on the duration of exposure. In this work, tomatoes seeds were exposed to long hours of simulated microgravity condition using a one-axis clinostat. The seeds were sown on a 1.5% combination of plant nutrient and agar-agar solidified medium in three Petri dishes. One of the Petri dishes was mounted on the clinostat and allowed to rotate at the speed of 20 rpm for 72 hours, while the others were subjected to the normal gravity vector. The anatomical sections of both clinorotated and normal gravity plants were made after 72 hours and observed using a Phase-contrast digital microscope. The percentage germination, as well as the growth rate of the normal gravity seeds, was higher than the clinorotated ones. The germinated clinorotated roots followed different directions unlike the normal gravity ones which grew towards the direction of gravity vector. The clinostat was able to switch off gravistimulation. Distinct cellular arrangement was observed for tomatoes under normal gravity condition, unlike those of clinorotated ones. The root epidermis and cortex of normal gravity are thicker than the clinorotated ones. This implied that under long-term microgravity influence, plants do alter their anatomical features as a way of adapting to the stress condition.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1130257Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 580
 D. Moore and A. Cogoli. Biological and Medical Research in Space. Springer, 1996 ISBN-13:978-3-642-646-942.
 M. Fujie, H. kuroiwa, T. Suzuki and T. kuroia. Organelle DNA Synthesis in the quiescent centre of Arabidopsis thaliana. (col). J. Exp.Bot. vol. 44, 1993, pp. 690-693.
 H. Mirsandi, T. Yamamoto, Y. Takagi, Y. Okano, Y. Inatomi, Y. Hayakawa and S. Dost. A Numerical study on the growth process of InGaSb Crystal, 2015.
 J. Jing, C. Haiying and C. Weiming. Transcriptome Analysis of Oryza sativa Calli under Microgravity, vol. 27; 2015 pp. 437 – 453. Doi 10.1007/s12217-015-9432-2.
 H. Q. Zheng, F. Han and J. Le. Higher Plants in Space: Microgravity Perception, Response and Adaptation. Microgravity Science and Technology, vol. 27, 2015, pp. 377 – 386. Doi: 10.1007/s12217-015-9428-y
 T. W. Halstead and F. R. Dutcher. Plants in space. Annual Review of Plant Physiology vol. 38, 1987, pp. 317–345.
 J. Z. Kiss, W. J. Katembe and R. E. Edelmann. Gravitropism and development of wild-type and starch-deficient mutants of Arabidopsis during spaceflight. Physiology of Plant, vol. 102, 1998, pp. 493–502.
 L. H. Levine, A. G. Heyenga, H. G. Levine, J. W. Choi, L. B. Davin, A. D. Krikorian and N. G. Lewis. Cell-wall architecture and lignin composition of wheat developed in a microgravity environment. Phytochemistry, vol. 57, 2001, pp. 835– 846.
 United Nations Office for Outer Space Affairs (UNOOSA). Teacher’s guide to plant experiments in microgravity- Human Space Technology Initiative. United Nations, New York, 2013.
 A. B. Simona, F. K. Matteo, E. S. Eva and V. A. Wilken-Jon. The Effects of Microgravity on the Photosynthetic Yield of Nannochloropsis Salina and Spirulina Platensis. International University Bremen, College Ring 6, 28759 Bremen, Germany, 2006.
 B. C. Tripathy, C. S. Brown, H. C. Levine and A. D. Krikorian. Growth and Photosynthetic Responses of Wheat Plants Grown in Space. Plant Physiology, vol. 110, 1996, pp. 801-806.