tissue, and transferred to clean flasks containing filter paper and 2 mL of water for 7 d, 30 C. For each experiment there were five replications of each treatment, and experiments were repeated three times. All chemicals employed were reagent grade. Test solutions were prepared fresh daily. In experiments which tested the activity gaseous hydrocarbons, dehulled seeds were incubated in open 6 cm Petri dish halves with layers of Whatman No. 1 filter paper. Dishes were placed in a 9 L desiccator which was continuously flushed with the gas under study for up to 48 h at 25 C. Gases were bubbled through water before passing over the seeds, and the atmosphere in the desiccator was maintained at 100% RH. Seeds were then transferred to Erlenmeyer flasks as described above and incubated for 7 d. 30°C. Butane(2.2% in nitrogen), propane(2.3% in nitrogen), and carbon monoxide(99%) were used as supplied(Airco).