SEMIPERMEABILITY OF SEED COVERINGS AND STIMULATION OF SEEDS

Abstract

The intake of salts by seeds was studied by means of electrical conductivity measurements. The amount of intake depends partly on the kind of seed used, and partly on the nature of the cation and anion of the penetrating salt. Seed coverings are frequently limiting factors on the amount and rate of salt entry. In the cereals, the passage of KNO3 was distinctly checked by the seed coats. When seed coats are intact, salts may be held superficially in the outer layers of the seed coat. Heavy losses of salts resulted in some cases by washing in water for even 1 min. Injured or broken grains showed high intake and small losses, relatively, on washing, because of the openings through the seed coats. The behavior of seed coverings in the presence of stimulants must be known to avoid failures with seed stimulation work done on a commercial scale. The paper is critical of Popoff''s seed stimulation work.