STIMULATION OF GERMINATION OF DORMANT LETTUCE SEED BY SULPHUR COMPOUNDS.

Numerous agents have been reported as effective in promoting germination of dormant lettuce seed. Borthwick and Bobbins (1) found that the percentage of lettuce seed germinating at temperatures above 25? C. is increased by high oxygen pressure. Thornton (17) reported that good germination was obtained at temperatures as high as 35? C. if the surrounding atmosphere contained from 40 to 80 per cent, of carbon dioxide. Shuck (14, 15), Flint (7), and Flint and McAlister (8) have reported on the influence of light on the germination of dormant lettuce seed. Denny (2, 3) and Miller (13) have studied the influence of certain sulphur compounds on the breaking of dormancy in the potato tuber. That certain sulphur compounds are also effective in breaking dormancy in lettuce seed was reported by the writers (16). The present paper is a more complete report of studies made on the influence of chemicals in stimulating germination of lettuce seed under conditions that result in poor germination if the seed is not given some special treatment.