To understand further the growth of tobacco during the first three weeks of germination, a time-course study of germinating flue-cured tobacco seeds was performed in light and in darkness with and without mineral nutrients. Dry weight per plant, hypocotyl length, and root length measurements for the first 21 days indicated the relative growth of the seedling when it is dependent on the reserves stored within the seed. Burial tests with substrates of different particle sizes indicated that emergence from a depth of six millimeters can occur in a coarse material and that the depth of burial from which emergence may occur decreases with decreasing particle size. Growth of seedlings in the absence of external sources of N, P, K, Ca, S, and Mg, respectively, indicated the relative amount of growth tobacco seedlings could make in the absence of each of these elements as compared with that of seedlings grown with complete mineral nutrition and in distilled water. These findings indicated an early requirement for N and K, more so than for the other elements tested.

(Full article published with kind permission from "Tobacco International")