Effects of long-term simulated microgravity on tomato seedlings

Abstract

Xu, D., Guo, S. and Liu, M. 2014. Effects of long-term simulated microgravity on tomato seedlings. Can. J. Plant Sci. 94: 273–280. Whether plants can adapt to a long-term microgravity environment is crucial to their reproduction in bioregenerative life-support systems in space. This research investigated the effects of simulated microgravity on Lycopersivon esculentum Mill. (cv. Dwarf Red-bell). Several indicators, namely germination ratio, percentage of cell membrane damage, malondialdehyde content (MDA), superoxide anion ([Formula: see text]) content, and mininucleolus, were observed 10, 20, 30, and 40 d after planting (DAP). Simulated microgravity [random positioning machine (RPM) treatment] barely had any effect on germination ratio, but it increased MDA, an index indicating membrane lipid peroxidation. Random positioning machine-treated samples had significantly higher [Formula: see text] content until 16 DAP, but these differences ceased after 21 DAP. Simulated microgravity damaged cell membranes, and the damage severity was positively related to the duration of the simulated microgravity treatment. Mininucleoli were more common in RPM-treated root tips than in the 1×g ones. In conclusion, simulated microgravity seriously disturbed tomato seedling growth by damaging cell membrane integrity, causing the accumulation of hazardous substances, and affecting the cell nucleus structure.

Elevated CO2 enhances photosynthetic efficiency, ion uptake and antioxidant activity of Gynura bicolor DC. grown in a porous‐tube nutrient delivery system under simulated microgravity

“…; Xu et al . ). However, there is little information on how plants respond to elevated CO 2 under microgravity conditions; these processes are far from being fully understood.…”

“…Many studies have focused on organism response to space factors at molecular, biochemical, physiological and morpho-anatomical levels. Previous research under microgravity during space missions and simulated microgravity using ground-based facilities has contributed greatly to our knowledge of the impact of gravity on leaf morphology, cell structure, carbon metabolism, gravity sensing mechanisms and gravity-mediated orientation of organisms in their spatial environment (Mortley et al 2008;Herranz et al 2013;Xu et al 2014). However, there is little information on how plants respond to elevated CO 2 under microgravity conditions; these processes are far from being fully understood.…”