How Space constraints can trigger positive outcomes UNIVERSITY OF NAPLES FEDERICO II DEPT. AGRICULTURAL AND FOOD SCIENCES Does ionizing radiation influence nutritional value of fruits in dwarf tomato? How Space constraints can trigger positive outcomes De Micco V., Aronne G., De Pascale S., Paradiso R., Vitaglione P., Arena C. demicco@unina.it

Space constraints Stress conditions Radiation Gravity Genetics Structure and function Physiology and biochemistry

Plants versus animals Arena et al. 2014. Acta astronautica 104: 419–431 De Micco et. Al. 2011. Radiat Environ Biophys 50: 1-19

Aims Tomato: candidate species for BLSSs To evaluate the effect of different X-rays doses on fruit traits of Solanum lycopersicum L. ‘Microtom’ plants irradiated at different phases of the life cycle Tomato: candidate species for BLSSs FOOD as countermeasure Foods derived from plants are rich in antioxidants which decrease or prevent the oxidation of other substances Candidate cultvar: Solanum lycopersicum L. ‘Microtom’ Compact size Short production cycle High yield Good nutritional value of the fruits

Phenological phases (I, II, III, IV IR) Experimental design X-rays doses 0 Gy (control) 1 Gy 0.3 Gy 10 Gy 50 Gy 100 Gy Dose rate 1 Gy/min Phenological phases (I, II, III, IV IR)

Analyses Fruit development Anatomical traits Nutritional traits Reproductive phenology (Number of blossoms, flowers and fruits) Size of fruits Fruit development Resin embedding and tissue thin sectioning Light and fluorescence microscopy Digital Image Analysis Anatomical traits Carotenoids Phenolic compounds Weights Sugar content Nutritional traits

Completion of the life cycle I IR II IR IV IR III IR Formed fruits after IR do not show differences in size but are characterised by lower fresh and dry weight at high X-rays doses when irradiated at early stages of development (I, II)

Reproductive phenology Number of ovaries Number of fruits

Fruit anatomy Anatomical responses are dependent on dose and phenological phase at irradiation Radiation-induced increased thickness of sub-epidermal layers rich in phenolics III IR similar to II IV IR: n.s

Autofluorescence of phenolics 0.3 10 100 Fluorescence due to phenolics increases according to the stage of development at the time of irradiation and according to the dose

Carotenoids and phenolics

Conclusions Radioresistence is strictly dependent on the dose and the phenological phase at the time of irradiation Very high doses in peculiar stages of plant development can be responsible for reproductive failure X-rays generally induce either an increase or decrease in cartenoids depending on single compounds Apart from a few compounds, X-rays induce an increase in phenolic compounds The results strengthen the hypothesis Can fresh tomatoes produced in Space help maintain a good state of health in astronauts thanks to the antioxidant components (increased by the exposure to radiation) which play a protective role on human organism?

General perspective Aims How to make more from less or from too much How to transform a constraint into an opportunity

Many thanks!