The thermal requirement for physical dormancy-break in Geranium carolinianum

摘要

dormancy break in Geranium carolinianum is a two-step process controlled by two different temperature regimes. Under high summer temperatures, seeds become sensitized (step-1 ), and during this stage they gain the ability to respond to PY-breaking temperature conditions but remain impermeable. Then with the onset of cool temperatures in autumn, seeds become permeable (step- II) at the micropylar water-gap complex (Gama-Arachchige et al 2010, 2012). The primary aims of this study were to quantify thethermal requirement for sensitivity induction using a thermal time model and to propose a mechanism for PY-breaking in the winter annual G. carolinianum.