Periods of Sensitivity to Chilling in Germinating Cotton

Abstract

Cotton seedlings (Gossypium hirsutum L.) were subjected to a 96 hr. chilling treatment (5[degree] or 10[degree]) after periods of germination at 31[degree] ranging from 0 to 48 hr. Inhibition of subsequent growth at a favorable temperature by chilling was dependent on level of low temperature and stage of seedling development when chilled. Two periods of chilling hyper-sensitivity were observed during germination: coincident with subjection of seed to a germination environment; and after 18 to 30 hr. of germination at 31[degree]. Subsequent growth of seedlings chilled after 12 to 18 hr. or 48 hr. of germination at 31[degree] was relatively unaffected. Chilling probably alters specifically time events that occur at the initiation of germination and after 18 to 30 hr. of germination, and that alteration of these germination processes affects long term subsequent growth of the plant.