Lunar-Soil Samples Nourish Some Garden Plants

Press, Volume CIX, Issue 32166, 9 December 1969, Page 15

Lunar-Soil Samples Nourish Some Garden Plants

(By ROBERT C. COWEN. natural science editor of the “Christian Science Monitor”) Botanists at the Manned Spacecraft Centre in Houston have been feeding plants on moon dust. They’ve been looking for harmful effects to earthly life. Instead, they’ve found a benefit.

An exotic lunar vitamin speeds a liverwort’s growth by 300 per cent Ferns thrive on it Even the homely lettuce finds it nourishing. This has opened a new line of research for the lunar botanists. Now they want to find out how plants make use of this apparently intractable, alien stuff.' It’s an Interesting scientific question. Also, these botanists see the remote possibility of gardens on the moon.

Dr Walter W. Kemerer, quarantine manager for the Lunar Receiving Laboratory in Houston, notes that the moon dust won’t dissolve in water. It’s soluble only to the extent of two-tenths parts per million. Yet, somehow, he says, “these plants are digesting this material—if you will, making the minerals available (for food).” Need For Quarantine “Quarantine” In Dr Kemerer’s title refers to the strict isolation that was imposed on the Apollo 11 astronauts and their moon samples that in-] eluded a hunt for possible danger to earthly life. Dr Kemerer’s investigators fed moon dust to microbes, animals, and plants. They found no danger. But they got a surprise from the plants. There is no doubt some of the plants “liked” their diet The liverworts and lettuce looked healthy in the laboratory jars here. Pop corn seedlings stand upright and green.

This doesn’t mean you’d gain much by sprinkling moon dust on your garden. As Dr Charles Walkinshaw, senior plant pathologist pointed out lettuce would grow better in good garden soiL But In the rather poor growing medium used for the tests, moon dust makes a difference. Dr Walkinshaw’s group used 33 types of plants for testing. Of these, 31 are economically important The fems and liverworts repre-

sent earth’s primitive plant forms. In all, about 4000 plants have been exposed to moon matter. Special Medium Dr Walkinshaw uses a cel-lulose-based growing medium called BR-8, to which he adds some plant food. Both test plants and “control” plants are grown on this. For the test plants, he enriches the medium with 0.22 grams of

moon dust per culture. That’s less than 0.5 per cent by weight He picked this particular medium because he can recover the moon dust from it Vermiculite or peat wouldn’t do. He couldn’t get the precious dust back. Of course, the moon matter will be altered somewhat by the plants feeding on it Even so, experimenters want every grain of it they can recover. The moon stuff resembles some earthly lavas except for

certain elements. It’s rather high in titanium and low in sodium and potassium, compared with terrestrial volcanic material. Still, the liverworts may like it for its volcanic character. These fleshy plants grow in the austere environment of lava flows. Perhaps it is not too surprising that they would feed on moon “basalt” But what does lettuce find in the stuff? Trace Material Dr Walkinshaw thinks the moon dust supplies some trace materials, some “growth (factor” that's effective in tiny amounts. This isn't just waiting in the medium for the roots to take it up like nitrates in your garden. Moon dust is too insoluble for that. The plants seem to be taking their nutriment directly from the moon dust itself.

He explains that lettuce is known to be able to do this sort of thing. The process may involve a direct exchange between plant and moon dust The plant for example, may exchange potassium for sodium or magnesium.

Botanists know very little about trace elements in plant nutrition on earth. Now, the moon dust raises another aspect of the problem.

1 Dr Walkinshaw hopes to try growing plants directly in ■ moon ‘soil” after Apollo 12 i or future flights. No one has done this yet. There’s too

little moon stuff to go around. But if moon soil is able to support plant growth, per : haps with the help of fertilisers, then the possibility of lunar gardens at future moon bases will be opened. Crops would have to be grown in a protected environment You would have to provide an atmosphere, water, proper lighting. You would have to enrich the moon soil, Dr Walkinshaw says. Water Source? On the other hand, he notes, the plants would provide food, oxygen, and maybe even pure water. They might live quite well on the waste water. If you then collected the vapour transpired

through the plants’ leaves, you would have pure, distilled water. A garden large enough to provide vegetables for a base would also provide a significant amount of purified water. .

A Garden Dream Scientists have leaned toward simple plants like algae in their inoon-garden schemes.. Dr Walkinshaw thinks regu-lar-vegetables, like lettuce, would be better. They would both look more homey and would' provide homelike salads. The fact that moon stuff does not harm such plants, even helps some of them, makes this prospect seem more feasible. But that is a dream of the indefinite future. What excites botanists now is the hunt for the moon dust “growth factor.” This • has switched their approach to the quarantine tests from a negative to a positive vein.

As Dr Kemerer notes: “On the quarantine tests, we asked, Ts this stuff harmful to life on earth?’ We didn't set out to stimulate growth of liverworts. Now we want to do the other half of the research and find out what’s happening”