Plant Pillow Preparation for the Veggie Plant Growth System on the International Space Station

Figure 1

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Percentages of germination and microbial contamination in preliminary lettuce seed tests of fuming surface sterilization methods_ Tests were conducted with ‘Waldmann's Green’ lettuce seeds that had microbial contamination_ Germination was tested immediately and following 1 month of storage for promising treatments_

Fuming Treatment	Germination	Contamination	Stored Germination
Bleach alone-12 h	96%	100%	-
Bleach+1 mL HCL-20 h	0%	0%	-
Bleach+0.5 mL HCL-1h	100%	0%	92%
Bleach+1 mL HCL-1h	100%	0%	4%
Untreated	96% – 100 %	100%	95%

Percentages of seeds germinating in the VEG-01 and VEG-03 tests_ Each value represents a percentage of the 12 seeds planted in 6 pillows_

Test	Plant	Germination – Flight (%)	Germination-Ground (%)
VEG-01A	‘Outredgeous’ lettuce	75	100
VEG-01B	‘Outredgeous’ lettuce	67*	75
VEG-01C	‘Profusion’ zinnia	100*	92
VEG-03A	‘Outredgeous’ lettuce	92	92
VEG-03B	‘Tokyo Bekana’ Chinese cabbage	92	100
VEG-03C	‘Tokyo Bekana’ Chinese cabbage	92	100

Percentages of germination (G) and contamination (C) observed for Veggie candidate flight seeds tested with different surface sterilization treatments_ Dashes indicate that these tests were not performed_ Values in bold indicate methods selected for flight seeds_

Treatment	‘Profusion’ Zinnia		‘Durango’ French Marigold		‘Outredgeous’ Lettuce		‘Tokyo Bekana’ Chinese cabbage
	G	C	G	C	G	C	G	C
Bleach + 0.5 mLHCL - 1h	80–100%	0%	70%	40%	100%	0%	100%	0%
Bleach + 1 mLHCL - 1h	80%	0%	70%	60%	-	-	100%	0%
Bleach + 0.5 mLHCL - 5h	30%	0%	10%	0%	-	-	-	-
70% EtOH – 5 min	90–100%	0%	30%	60%	80–100%	20–40%	100%	100%
70% EtOH – 10 min	-	-	-	-	-	-	92%	20%
Untreated	67–100%	20–40%	60–100%	100%	90–100%	20–80%	100%	100%