Plant Responses to Microgravity Environments

Plants evolved under a constant gravity vector, which informs key developmental processes ranging from cell division and elongation to directional growth. In microgravity, the absence of a unidirectional gravitational cue triggers profound alterations at multiple organisational levels. Morphologically, roots and shoots display reduced directional bias, altered cell wall dynamics and changes in organ architecture. Physiologically, microgravity can uncouple cell proliferation from cell growth, disrupt ribosome assembly, modulate phytohormone distribution and induce oxidative stress. At the molecular level, transcriptome and proteome shifts reveal extensive reprogramming of post-transcriptional regulation, epigenetic marks and stress-related pathways. Studies aboard orbiting platforms demonstrate that select genotypes adapt more efficiently by reducing the metabolic cost of spaceflight responses, hinting at the potential for genetic or habitat manipulation to optimise growth. Beyond fundamental insights into gravitational sensing, microgravity research underpins strategies for crop production in life-support systems, informs terrestrial agriculture through novel stress resilience mechanisms and guides the use of in situ resources, such as lunar or Martian regolith, for extraterrestrial cultivation.

Research from Nature Portfolio

Simulated reduced-gravity and hypergravity experiments in Arabidopsis cell cultures reveal that altered gravity destabilises the balance between cell proliferation and growth. Under simulated microgravity and fractional gravities, cells exhibit delayed ribosome biogenesis, shifts in cell-cycle regulator expression and chromatin remodelling, emphasising that gravity influences both structural and epigenetic controls of division and expansion.

Investigations of Arabidopsis grown in lunar regolith samples from Apollo missions show that while germination and development are feasible, plants display slow growth and stress-associated morphologies. Gene expression profiles indicate ionic and oxidative stress signatures akin to salt or metal exposure, underscoring the need to mitigate regolith-induced stresses when utilising extraterrestrial substrates for bioregenerative life-support.

Plant Responses to Microgravity Environments publication trend

The graph below shows the total number of articles in plant responses to microgravity environments across all publications each year (not limited to Nature Index journals).

Technical terms

Microgravity: An environment in which the apparent weight of objects is near zero due to free-fall or orbital conditions.

Gravitropism: The growth orientation response of plants to the direction of gravity.

Clinostat: A device that rotates plants to negate the directional effect of gravity, serving as a ground-based microgravity analogue.

Ribosome biogenesis: The cellular process of synthesising and assembling ribosomal RNA and proteins into functional ribosomes.

Epigenetics: Heritable changes in gene expression that do not involve alterations to the DNA sequence, including DNA methylation and histone modifications.

Reactive oxygen species (ROS): Highly reactive molecules derived from oxygen that can cause oxidative damage and serve as signalling mediators in stress responses.

References

1. Comparison of Microgravity Analogs to Spaceflight in Studies of Plant Growth and Development. Frontiers in Plant Science (2019).
2. Simulated microgravity, Mars gravity, and 2g hypergravity affect cell cycle regulation, ribosome biogenesis, and epigenetics in Arabidopsis cell cultures. Scientific Reports (2018).
3. Plants grown in Apollo lunar regolith present stress-associated transcriptomes that inform prospects for lunar exploration. Communications Biology (2022).
4. Novel, Moon and Mars, partial gravity simulation paradigms and their effects on the balance between cell growth and cell proliferation during early plant development. npj Microgravity (2018).