Experiments on plants grown in space. Status and prospects.

Space flight provides a unique capability to gravitational research by providing an environment in which gravity can be manipulated below the Earth norm of 1 to a state comparable to weightlessness. Although space experiments with seeds and plants have been conducted for almost 25 years, we are only now entering an era that promises the capability of routinely conducting controlled plant experiments in space. Results from experiments with higher plants and seeds flown thus far in both manned and unmanned spacecraft from both the USA and USSR are briefly summarized. An overview of the current status of space biology experimentation as it relates to plants is presented and present and future opportunities to conduct plant experiments under space flight conditions are discussed.