Development of plant protoplasts during the IML-1 mission.

Abstract During the 8 day IML-1 mission, regeneration of cell walls and cell divisions in rapeseed protoplasts were studied using the Biorack microscope onboard the Space Shuttle “Discovery”. Samples from μ-g and 1g protoplast cultures were loaded on microscope slides. Visual microscopic observations were reported by the payload specialist Roberta Bondar, by down-link video transmission and by use of a microscope camera. Protoplasts grown under μ-g conditions do regenerate cell walls but to a lesser extent than under 1 g. Cell divisions are delayed under μ-g. Few cell aggregates with maximum 4–6 cells per aggregate are formed under μ-g conditions, indicating that microgravity may have a profound influence on plant cell differentiation.