Recently, the field of lunar agriculture has taken a big step forward. Scientists reported on the first-ever plants planted in lunar soil. Although the products of this process are far from edible food, the team's success marks an important milestone in the efforts to maintain the lunar base and carry out deep space missions. It also provides useful insights into the composition and feasibility of extraterrestrial soil.
It may not be surprising that lunar soil is in short supply on earth, so carrying out such experiments is not a simple task. So far, scientists have successfully sprouted in simulated lunar soil from the Arizona desert, and some research teams have developed greenhouse like modules that can be transplanted to the moon. In 2019, China's chang'e-4 probe germinated the first seeds ever in a micro biosphere on the lunar surface - although they died less than 24 hours later.
The latest breakthrough in this field comes from research led by Anna Lisa Paul and rob ferl of the University of free Florida. In fact, they applied for experiments on lunar soil three times in 11 years. Because these soils were collected during Apollo 11, 12 and 17 missions, they are of great historical significance, and scientists borrowed 12 grams of precious materials from NASA to plant a small garden for themselves.
In the experiment, the scientists used thimble sized pots, filled each with a gram of lunar soil, wetted it with nutrient solution and sowed the seeds of Arabidopsis plants. At the same time, the team planted the same seeds in simulated lunar soil, simulated Martian soil and soil from the earth's extreme environment as a control experiment. Despite prior skepticism, scientists were pleasantly surprised to find that almost all lunar soil produced germinating plants.
"We were surprised. We didn't predict this. It tells us that the lunar soil doesn't interfere with hormones and signals involved in plant germination," Paul said
But this is not plain sailing. Plants growing in lunar soil develop slowly, and many of them show signs of stress, as well as the various gene expressions scientists expect to see in plants affected by salt, metals and reactive oxygen species.
"At the genetic level, these plants are pulling out the tools commonly used to deal with stress sources, such as salt and metals or oxidative stress, so we can infer that these plants believe that the lunar soil environment is stressful. Finally, we hope to use gene expression data to help solve how we can improve the stress response so that plants, especially crops, can grow in the lunar soil with little impact on their health." Paul said.
An interesting harvest is that plants growing in more mature lunar soil - soil exposed to more cosmic winds - show more signs of stress, while less mature soil will see plants have a smoother journey. As part of the follow-up study, scientists will now continue to study the relationship between plant health and soil composition and the possible impact of plants on the soil itself.