Figure 4.

Abscisic acid (ABA) contents, and regulation of ABA‐ and ethylene‐related genes implicated in the cold‐induced secondary dormancy. (a) ABA contents in sugar beet seeds extracted from fruits incubated at the indicated temperature regimes (n = 5 relicates). (b) ABA metabolism and signalling. (c) Transcript abundances of ABA‐ and ethylene‐related genes in sugar beet seeds incubated at the indicated temperature regimes: The red line represents fruits incubated at 10°C, the blue line incubated at 5°C and the transition to purple represents secondary dormancy induction and maintenance (T _SD, 5°C until 432 h and subsequent incubation at 10°C). Results from the transcriptome analysis of KWS310: CPM, counts per million mapped reads of n = 3 RNA samples (biological triplicates each from 100 sugar beet seeds); see Figure 3a for detail sampling scheme and Supporting Table S1 for the Beta vulgaris gene names and IDs. (d) RT‐qPCR analysis of transcript abundances of the contrasting KWS310 and KWS257 seedlots (n = 3 RNA samples). For primer sequences and reference genes see Supporting Table S1; note the contrasting germination patterns of these seedlots. See main text for gene abbreviations. Mean values ± SEM are presented. RT‐qPCR, reverse‐transcription quantitative polymerase chain reaction [Color figure can be viewed at wileyonlinelibrary.com]