Fig. 2: Regulation of PD network is crucial for variable cold processing by buds.

a Quantification and spatial distribution of callose at the cell level in the shoot apical meristem of aspen buds, after 11 weeks of short days and in response to 4 weeks of constant and variable cold temperatures. Graph displaying callose quantification per cell based on the sum of the mean signal intensities at the cell periphery (data points represent individual cells). Quantification was based on six meristem surfaces per condition, each with an area of 7515 µm², containing 220–280 cells. Statistical analysis was performed using one-way ANOVA (p < 0.0001) followed by Tukey’s test. Error bars represent the 95% confidence interval of the difference, and asterisks (****) denote a significant difference. b Visual representation of PD-associated callose levels per cell. The color legend bar indicates the sum of the callose mean signal intensities at the cell periphery. c Response of WT and abi1-1 buds to constant and variable cold temperatures. WT and abi1-1 plants grown under short-day (SD) conditions for 11 weeks were exposed to either 4 weeks of constant cold or variable cold temperatures (as in Fig. 1a) and then transferred to warm, long-days, and bud break was recorded. d The percent bud break of WT and abi1-1 plants subjected to constant cold versus variable cold temperatures. The experiment was repeated at least twice with similar results, and the bud-break percentage is shown with data from 10–15 plants.