Biometric anatomy of seedlings developed onboard of Foton M2 in an automatic system supporting growth
- Paper number
IAC-06-A1.5.07
- Author
Dr. Veronica De Micco, Università degli Studi di Napoli “Federico II”, Italy
- Coauthor
Prof. Giovanna Aronne, University of Naples "Federico II", Italy
- Coauthor
Mr. Michele Scala, University of Naples "Federico II", Italy
- Year
2006
- Abstract
Long time has passed since the first experiment aiming to germinate seeds and to grow plants in Space, was successfully conducted. However, numerous aspects of plant biology still need to be investigated before the establishment of self-sustaining human colonies in Space supported by Bio-regenerative systems. Higher plants have evolved in 1-g terrestrial environment, and their development on Earth is mediated by several factors among which gravity plays a key role. The present study is based on the results of previous experiments conducted in simulated microgravity and is aimed to investigate the effect of real microgravity on seed germination, seedling development, mobilisation of starch and phenolics among different organs, and vascular differentiation in soy. In fact it has been argued that these phenomena are mediated by gravity. Moreover, they not only affect the correct functionality of the vegetal system but they have also influence on softness of tissues, food digestibility, nutritional value and consequently on overall quality of the fresh food. The experiment was selected for the flight onboard of FOTON M2 satellite, which provides several days of tests in microgravity that are enough for seed germination and complete development of seedlings. A long pre-flight preparation preceded the flight phase because we designed and assembled the growth support system for seedlings. The developed hardware is fully automatic, does not require any external control signal and is made of three modules that accommodate batteries, bags for water and chemical fixative, and the growth chamber where seeds are placed. It can be programmed to irrigate seeds with water after the satellite has reached the orbit. This operation starts the experiment: seeds absorb water and germinate. Seedling development can be stopped after 5-7 days by the injection of a chemical fixative so that morphological and anatomical analyses can be performed in laboratory after retrieval. The experiment was successfully conducted flying from 31st May 2005 to 16th June 2005. A control experiment was then conducted on Earth in growth chambers programmed to create the same temperature and humidity conditions as those experienced in Space and recorded by probes. Observed parameters regarded percent germination, morphology and biometry of radicle and cotyledons. Anatomical parameters were studied on thin sections of tissues obtained by rotative microtome after embedding in resin. Sections were stained with dyes to enhance contrast and to visualise specific compounds. Epi-fluorescence microscopes equipped with different lamps and filters allowed the observation of lignified tissues and phenolic compounds accumulated in specific regions of the seedlings. Quantification of anatomical and cytological parameters was made on digital microphotographs subjected to computerised image analysis. The analysis regarded parameters such as size and shape of cells, thickness of cell walls, incidence of lignified areas, amount and distribution of starch and phenolics. The comparison between seedlings developed in Space and those developed on Earth was made on the basis of statistical analysis of the parameters described above. Results were discussed considering the relations between structure and functions of plants in both Earth and Space environments.
- Abstract document
- Manuscript document
IAC-06-A1.5.07.pdf (🔒 authorized access only).
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