Effect of Microgravity on growth, Ultrastructure, phenol, flavonoid, and inhibition of DPPH radical in Hyoscyamus niger L. Seedlings

 Microgravity is one of the environmental stresses in space that affects on the structure of cellular organelles and metabolites in plant. In the present research, the effect of microgravity in times 3, 7 and 10 days on root and hypocotyl growth rate, fresh and dry weight, cell and organelles ultrastructure with Transmission Electron microscope (TEM) and some antioxidative capacity ( phenol, flavonoid and inhibition of DPPH radicals) were investigated in henbane (Hyoscyamus niger L.) seedling. The results showed that microgravity led to increase root and hypocotyle length as compared to control. Amydons were spread throughout the cell in microgravity treatment, while in control samples, they were deposited on the cell wall in the direction of gravity. Mitochondria were variable in shape and number. The endoplasmic reticulum in 10-day treatment was more voluminous and longer than the control. Also, the vacuole was observed more voluminous as compared to control. Total phenol, flavonoid, and inhibition of DPPH radicals increased significantly(P < 0.05). It seems, cellular changes and secondary metabolism induced under microgravity are related to oxidative stress.