Table 1.

Mean and s.d. of the damage threshold for fresh leaves (n = 3) and fresh roots (n = 2)

	Damage threshold (kGy)
Element	Leaves (fresh)	Roots (fresh)	C. elegans (fresh)	C. elegans (lyophilized)
Potassium	45.8 (7.67)	8.27 (3.68)	*	10 × 103
Calcium	14.1 (10.7)	†	*	30 × 103
Manganese	19.7 (14.8)	23.2 (*)	*	40 × 103
Iron	66.3 (‡)	†	1.5 × 103	40 × 103
Zinc	46.6 (7.36)	†	*	40 × 103

The damage threshold is defined as the point where the damage metric, $\stackrel{\mathrm{\_}\mathrm{\_}\mathrm{\_}\mathrm{\_}}{{\chi }_X^2}$ [eqn (3)], for the sample deviates from 1 by ±0.5. Damage thresholds for C. elegans are shown for comparison (Jones et al., 2017).

*Statistically limited.

†No damage observed.

‡Damage observed in only one specimen.