We received a couple of questions from the students at ECG Henry-Dunant in Switzerland. See my answers below!
Why grow an aromatic herb instead of a food crop?
We are still in the pilot phase of AstroPlant, so we need to check if the kit works properly. The plant should be able to grow properly and the sensors should give good readings. Basil is a herb, and therefore more sensitive to changes in its environment. For example, if there is not enough water the leaves will start hanging down almost immediately. This allows us to see if the kit is balanced well. After basil we will start growing more food crops, as they are more important to the MELiSSA goal of sustaining astronauts in a space life support system.
How will the data then be used?
The data that is collected for the basil is very useful! Scientists at MELiSSA are using all AstroPlant data to build a mathematical model of the growth of plants. All aspects of a plant and its environment are used in this model, so it is very elaborate. While ESA is mostly interested in the food crops, the model MELiSSA is making can also be used for making predictions about other plants. The data from basil is useful for this because it is a plant unlike most food crops. By collecting data from different ‘kinds’ of plants (monocotyledons, dicotyledons, herbaceous and woody species), the model becomes more comprehensive and thus more useful for scientists and later on farmers as well.
Why do we need to treat the seeds with alcohol and detergent?
Depending on where the seeds come from, they have a lower or higher risk of carrying pathogens on them. If you grow the seeds without sterilising them, these pathogens will infect your plant immediately. The alcohol kills the pathogens and the detergent is added to make sure that the alcohol reaches all spots and ridges on the surface of the seed. Just as the pathogens can’t harm the seed embryo because of the sturdy seed coat, the alcohol also won’t affect the embryo itself.
Why do we start growing the plant on rock wool? What are its properties?
We (well, you actually) are experimenting with a new way to start the root growth. In the beginning, the seed planted in the center of the kit has a very small root system, and seems to get too little water from the irrigation ring. To compensate this, we want to add a substrate that is better at retaining the water than the clay pebbles are. Rockwool is very good at this, and so makes sure that the roots can get enough water during their first growth phase.
Comment déterminer l’air de la feuille de basilic?
[ How do we determine the area of the basil leaf? ]
I assume this question is about the surface of the basil leaf? This is explained in the Growth Protocol under 4B ‘manual measurements’: https://astroplant.gitbook.io/join-mission/astroplant-growth-protocol
What is the petiole?
The petiole is the small connection between the leaf and the stem or branch, and is not considered part of the leaf (for calculation of the leaf area). It is shown in figure 6 (also under 4B).
If the project becomes doesn’t succeed, what will be the next project?
First, we need to make sure the setup of the kit works. We are finding out which settings work well and which don’t through the feedback we get from users like yourselves and our own tests. If your first basil plant dies early, try another one: science is about repeating, improving and persevering until you succeed! We will continually improve the Growth Protocol, so the next time your experiment will probably go somewhat differently (and hopefully better!). If the basil plants grow well, we can continue by growing wheat and soy. Those crops are two of ESA’s favourite candidates for astronaut food.