The mutation induced by space conditions in Escherichia coli

Table 2 The Arg⁺ reversion frequency of strain CSH108 in different boarding ways

Sample	Group	Arg+ reversion frequency (× 10-8)
Boarding sample	Group I	2.9
	Group II	1.8
	Group III	26.3
Ground control	A(1)	1.2
	B(2)	2.8

(1) Ground control: Strain was kept at room temperature; (2) Ground control: Strain was stored in freezer (-60 °C).