Living plant systems: how robust are they in the absence of gravity?
The following hierarchical levels can be recognised in plant systems: cells, organs, organisms and gamodemes (interbreeding members of a community). Each level in this 'living hierarchy' is both defined and supported by a similar set of sub-systems. Within this framework of plant organization, two complementary questions are relevant for interpreting plant-oriented space experiments: 1) What role, if any, does gravity play in enabling the development of each organizational level? and 2) Does abnormal development in an altered gravity environment indicate sub-system inefficiency? Although a few representatives of the various organizational levels in plant systems have already been the subject of microgravity experiments in space laboratories--from cells in culture to gamodemes, the latter being found in some Closed Environment Life Support Systems--it would be of interest to investigate additional systems with respect to their response to microgravity. Recognition of the sub-systems at each level might be relevant not only for a more complete understanding of plant development but also for the successful cultivation and propagation of plants during long-term space flights and the establishment of plants in extra-terrestrial environments.
Barlow
P W
PW
IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Long Ashton, Bristol BS41 9AF, U.K.
D000222:Adaptation, Physiological / Q000502:physiology; D005075:Biological Evolution; D018522:Gravitropism / Q000502:physiology*; D059828:Plant Cells; D063245:Plant Development; D018521:Plant Physiological Phenomena; D013026:Space Flight; D013598:Systems Theory; D014893:Weightlessness