Improved growth andproliferation of cultured tobacco cells after long-period exposure to the 2D-clinostat

Plant cell cultures are precious tools for investigating the response of plants to altered gravity at the cellular level. In the present study, the effects of clinorotation on the growth and cell cycle progression of cultured Nicotiana tabacum cells were investigated. Exposure to 2D-clinostat for 12 h increased the percentage of the cells in the G1 phase from 80 to 83.2%, while significantly reduced the percentage of those cells at the G2/M transition, compared to their corresponding control cells. When the duration of exposure was extended, the rate of cells transition to the M phase increased, ultimately promoted the exponential growth phase after 168 h. During the first 24 h of clinorotation, a significant rise in the levels of simple sugars within the cells was observed. The ferric-reducing antioxidant power (FRAP) of tobacco cells exhibited a downward trajectory that continued until 48 h. This research showed the influence of clinorotation on plant cells dependent on the exposure duration. The cells exhibited signs of stress after a short exposure, possibly due to high levels of soluble sugars that could impede cell advancement in the G1 phase by negatively affecting radical scavenging capacity (RSC). Upon extending the exposure duration to 168 h, the cells were adapted to the altered gravity conditions and improved their growth, probably due to a rise in auxin and gibberellin production. The results suggest cultured cells are a viable candidate, for examining plants in long-term space missions.

Graphical abstract