TEMPERATURE-INDUCED DIFFERENTIAL CONTRACTION IN THE SOMATIC CHROMOSOMES OF TRILLIUM ERECTUM L.

Abstract

When root tips of Trillium erectum L. are exposed to low temperatures the chromosomes contain regions of reduced diameter and staining capacity. The positions of these regions are constant within the species.The number of "differentiated regions" per nucleus changes with the duration of cold treatment, and at 3 °C. reaches a maximum after 96 hr.The visible differentiation produced by cold disappears within a few hours when the material is returned to higher temperatures.Low temperatures cause non-differential parts of chromosomes to be more contracted than in untreated material, while differentiated regions are unaffected or less contracted than in the controls. The amount of "differentiation" observed is apparently determined by the differential contraction of these parts.