The European white birch, scientifically known as Betula pendula, and its variant, B. pendula 'Dalecarlica' are characterized by a serrated leaf margin that enhances their aesthetic appeal. However, the lobed leaf trait can undergo random and spontaneous reversion to the typical ovoid or cordate shape during asexual reproduction. Investigating and elucidating the molecular mechanisms underlying this unpredictable reversion mutation is essential for comprehending the birch leaf development process. In this research, we employed a non-lobed-leaf mutant derived from a lobed-leaf birch clone during plant tissue culture. We adopted a multi-omics approach, including whole-genome resequencing, transcriptome sequencing, and methylation profiling, to analyze and compare genomic variations and gene expression modifications. The study revealed that the 24 variant genes affected by 1464 SNP/InDel sites in the genome of the non-lobed-leaf mutant are not associated with leaf development. While the overall methylation level in the mutant's genome closely resembles that of the serrated-leaf birch, ten genes exhibit differential methylation accompanied by differential expression. Transcriptome sequencing demonstrated that the differentially downregulated genes in the mutant are significantly enriched in the GO:0009733 (response to auxin) and GO:0009734 (auxin-activated signaling) pathways. Validation through McrBC-PCR and qRT-PCR confirmed differential methylation and expression of BpIAA9 in the reversion mutant. The elevated methylation level in the BpIAA9 promoter leads to reduced expression, resulting in changes in the expression of auxin-responsive genes. This, in turn, leads to a transcriptional downregulation enrichment effect in auxin-related pathways in the reversion mutant, ultimately inhibiting the regulation of leaf veins by auxin during their development.

The liquid droplet cooling technique for fast scanning chip calorimetry (FSC) is introduced, increasing the cooling rate for large samples on a given sensor. Reaching higher cooling rates and using a gas as the cooling medium, the common standard for ultra-fast temperature control in cooling, requires reducing the lateral dimensions of the sample and sensor. The maximum cooling rate is limited by the heat capacity of the sample and the heat exchange between the gas and the sample. The enhanced cooling performance of the new liquid droplet cooling technique is demonstrated for both metals and polymers, on examples of solidification of large samples of indium, high-density polyethylene (HDPE), and poly (butylene 2,6-naphthalate) (PBN). It was found that the maximum cooling rate can be increased up to 5 MK/s in room temperature environment, that is, by 2 orders of magnitude, compared to standard gas cooling. Furthermore, modifying the droplet size and using coolants at different temperatures provide options to adjust the cooling rate in the temperature ranges of interest.