MULTI-TROP aims to investigate the effect of different external stimuli (gravitropism, hydrotropism and chemotropism) on growth orientation of seedling roots. Being the gravitropism the prevalent orientation’s driver on Earth, it is needed a micro- gravity condition to investigate and clarify the role of the other two main stimuli (hydrotropism and chemotropism).
The experiment will be performed in dark condition, in the BIOKON container and will be integrated at launch site. Seed imbibition will start immediately but germination will occur in microgravity conditions. Root growth will be interrupted on board the ISS by automatic injection of the chemical fixative stored in the EUs, by crew member switching on the BIOKON.
At the end of the experiment (lasting few days) three different scenarios are expected:
1)the chemotropism prevails on the hydrotropism: roots grow only in the substrate with the nutrient solution
2)the hydrotropism prevails on the chemotropism, the roots grow indifferently in both substrates
3)the response of roots to gravity is much more intense than that of the other stimuli: the roots grow in all directions.
