Developing A Method For Mimicking Micro- To Zero Gravity To Enable Testing Models For Gravity Perception
Location
Hager-Lubbers Exhibition Hall
Description
PURPOSE: There are two dominant models for the perception of gravity by plant cells: the starch-statolith model (in which sedimenting starch grains act as the gravity sensor); and the gravitational pressure model (in which the entire protoplast acts as the gravity sensor). While previous physiological studies have demonstrated that the gravitational pressure model better explains the observed phenomena, we would like to follow up with genetic studies. To do this, we would like to develop a method for comparing physiological and genetic responses of Arabidopsis grown on the International Space Station, with those grown on Earth in an environment that mimics microgravity. SUBJECTS: Arabidopsis thaliana (Landsberg erecta as well as various mutants) seeds were used in this study. METHODS: Seeds were germinated and the roots grown into media of various densities. Curvature toward or away from the vectors of gravity and blue light were measured from time-lapse images collected over 24-hours. ImageJ was used to calculate the change in root tip orientation by measuring the initial and final orientation relative to the direction of gravity, as well as the growth rate. RESULTS: We successfully developed chambers for visualizing tropistic responses of the tiny roots of Arabidopsis. Physiological experiments indicate that increasing the density of the external medium decreases the gravity response. Additionally, treated roots were harvested to determine whether increasing the density of the external medium mimics microgravity at the genetic level. CONCLUSIONS: We were able to develop a method for growing Arabidopsis in media of different densities. Preliminary results indicate that physiological responses obtained with these methods on Earth mimic the responses reported from the ISS and support the gravitational pressure model for gravity sensing. We await our qPCR results to determine whether our results on gene expression mimic those found in experiments aboard the ISS.
Developing A Method For Mimicking Micro- To Zero Gravity To Enable Testing Models For Gravity Perception
Hager-Lubbers Exhibition Hall
PURPOSE: There are two dominant models for the perception of gravity by plant cells: the starch-statolith model (in which sedimenting starch grains act as the gravity sensor); and the gravitational pressure model (in which the entire protoplast acts as the gravity sensor). While previous physiological studies have demonstrated that the gravitational pressure model better explains the observed phenomena, we would like to follow up with genetic studies. To do this, we would like to develop a method for comparing physiological and genetic responses of Arabidopsis grown on the International Space Station, with those grown on Earth in an environment that mimics microgravity. SUBJECTS: Arabidopsis thaliana (Landsberg erecta as well as various mutants) seeds were used in this study. METHODS: Seeds were germinated and the roots grown into media of various densities. Curvature toward or away from the vectors of gravity and blue light were measured from time-lapse images collected over 24-hours. ImageJ was used to calculate the change in root tip orientation by measuring the initial and final orientation relative to the direction of gravity, as well as the growth rate. RESULTS: We successfully developed chambers for visualizing tropistic responses of the tiny roots of Arabidopsis. Physiological experiments indicate that increasing the density of the external medium decreases the gravity response. Additionally, treated roots were harvested to determine whether increasing the density of the external medium mimics microgravity at the genetic level. CONCLUSIONS: We were able to develop a method for growing Arabidopsis in media of different densities. Preliminary results indicate that physiological responses obtained with these methods on Earth mimic the responses reported from the ISS and support the gravitational pressure model for gravity sensing. We await our qPCR results to determine whether our results on gene expression mimic those found in experiments aboard the ISS.