Figure 1.

Arabidopsis seeds remain dormant when the testa is removed but germinate when exposed to cyanide vapors. Seeds lacking the testa are shown in A to C 3 d (A) and 28 d (B and C) after testa removal. The seed in C was exposed to KCN vapors for 3 d beginning 25 d after testa removal. D, Germination percentages after 5 d for intact seeds exposed to water vapor or KCN vapor for 2 d, and for seeds with the testa removed exposed to water vapor, KCN vapor, or KCN vapors in the presence of c-PTIO. Each experiment was repeated at least three times with five to 14 seeds per treatment. Bars with different lowercase letters are significantly different with P < 0.05.