Effects on Plants

     Through experiments done in microgravity, scientists have discovered that plants are greatly affected by the severe difference in gravitation from their natural environment. The importance of growing plants in space will continue to increase in the next decades as longer spaceflights are planned. Due to the limit of supplies that can be transported to space, food must be produced when needed in larger quantities. This will also provide fresh foods, which are beneficial due to their nutritional content and the psychological stimulation.


     Plants orientate their roots and coleoptiles based on gravity in a process called gravitropism. In gravitropism, statoliths signal to a plant in direction the gravitation is. Starch grains fall within the cell, and as the cell perceives this, it reacts depending on its position in the shoot (Plant Physiology). In positive gravitropism, root cells grow down, and in negative gravitropism, plant shoots grow up.


     Even the genetic code of plants is affected by microgravity, as seen in Arabidopsis, a member of the mustard family and a species often used in scientific experiments because it has a rapid life cycle, it can be cultivated easily in respricted spaces, prolific seed production, and large number of mutant lines (Tair). Of the 10,000 nonredundant cDNAs of Arabidopsis seedlings, 50 were expressed differently in microgravity (Reddy, 2003).