The state of gravity sensors and peculiarities of plant growth during different gravitational loads

Abstract

In the primary roots of lettuce shoots grown under altered gravitational conditions - 180° inversion on the centrifuged clinostat, horizontal clinostat and in dynamic weightlessness - localization of the cellular organelles, cell morphology and peculiarities of growth have been studied. Significant changes took place in the localization of amyloplasts on the horizontal clinostat. The changes of amyloplast position in the cap cells on the horizontal clinostat and under weightlessness are similar. A change of the normal shoot position (180° inversion and horizontal clinostat) causes an inhibition of growth. Weightlessness increases the length of axial organs and cells in the zone of elongation, but decreases the mitotic index in comparison to the centrifuged control. The analysis of the formation of generative organs has been carried out for Arabidopsis plants grown on board the orbital station Salyut-6. The ability of plants to undergo vegetative growth and to pass through early phases of generative development under weightlessness was confirmed.