Spatial Lipidomic Profiling Reveals Distinct Lipid Distribution Patterns in Poplar Buds During Growth and Dormancy

Dormancy is a critical adaptive feature for trees to respond effectively to environmental changes. Understanding the comprehensive mechanisms regulating dormancy in poplar is vital for the genetic improvement of forest trees. However, previous studies have typically used mixed-sample extraction, which fail to capture spatial tissue-specific responses. This study provides precise spatial lipidomics analysis of poplar buds during phases of growth and dormancy by employing an innovative technique combining liquid chromatography-tandem mass spectrometry with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) for precise spatial lipidomics analysis of poplar buds during phases of growth and dormancy. MALDI-MSI revealed that most phospholipids were uniformly distributed across all tissues in growing buds but localized in the bud axis during dormancy. Moreover, triacylglycerols, which serve a storage function, were observed to accumulate mainly within the shoot apical meristem tissue during dormancy. These findings highlight the unique spatial distribution patterns of lipids during bud growth and dormancy in poplar, emphasize the role of lipid metabolism in adapting to seasonal changes, and provide new approach for elucidating the lipidomics of seasonal growth patterns in trees.