Don't look for any forests or gardens to sprout in space, but scientists are interested in the effect of growing plants and trees in a gravity-free environment. Such information could prove invaluable to any future plans to grow food on a manned space station.
On Earth, it might lead to more nutritious agricultural products or aid industrial processes such as the production of paper.
The two-week delay in the launch, and the lower-than-planned orbit of Challenger due to an engine failure, have adversely affected a few of the experiments aboard. But at this writing, the shuttle crew was still scheduled to stay aloft for the planned seven days. As part of the mission, the astronauts are studying the growth of mung beans, oats, and pine seedlings in space. Preliminary results are that the plants are growing fine.
In particular, the crew is testing the effect of zero gravity on the formation of lignin, a natural polymer in plants that binds cells together and gives them the mechanical support to grow upward.
Lignin is something of a hero in the plant world. Not only is it responsible for the woody structure of trees, but it also provides resistance to decay, repels water, and acts as an antibiotic.
Yet the compound does have a few irksome traits. It can't be digested by humans, so it reduces the use of certain plants as food. It also burns up considerable energy derived from photosynthesis during its formation in plants.
Thus, if a way could be found to control the formation of lignin, such as under ``microgravity'' conditions, theoretically, more energy would be available for the production of edible compounds in plants. This could lead to better food products.
Lignin is also a nuisance for paper companies. They have to get rid of the substance when extracting cellulose to make paper. Reducing the proportion of lignin in trees from its current level of about 25 percent could make their jobs easier.