Gas-priming as a novel simple method of seed treatment with ethylene, hydrogen cyanide or nitric oxide

The gases used: ethylene (C2H4), hydrogen cyanide (HCN) and nitric oxide (NO) showed a high activity as inductors of germination in primary dormant or non-dormant seeds exposed to stress or suboptimal temperatures. So far, research on the role of ethylene, hydrogen cyanide and nitric oxide has involved these gases during seed germination. This work describes gas-priming as a novel method for treating air dry seeds of the genus Amaranthus serving as a model. Effects of C2H4, HCN or NO applied to dry seeds were similar to those obtained when the gases were used during seed germination for an identical period of time. Application of the gases to air dry seeds presents a new opportunity to study the role of those gases in germination of dormant and non-dormant seeds and to constrain effects of the gases from time 0. The prolonged treatment time for dry seeds (24 h) is convenient because if the treatment is started in the morning, there is sufficient time the next day for further experiments to begin, e.g. germination test in water or in solutions of other compounds. Moreover, it is important that the gas-treated seeds can be stored or transported prior to use. The gas-priming method allows to prepare treated seed samples which can be used in experiments either immediately or after storage in open air or in a closed container. Gas-priming with C2H4, HCN and NO is a simple and useful treatment of air-dried seeds, which opens up new useful possibilities for basic research on the role of those gases in releasing dormancy and seed germination of various plant species. In addition, the method may prove very useful in horticulture and agriculture in improving germination of gas-sensitive seeds.