Phenotypic and Metabolic Variations Induced by Autopolyploidization in Chinese Jujube Cultivars

Autopolyploidization is critical to plant evolution and breeding, but systematic studies on its effects in woody plants remain limited. To address this gap, a systematic investigation covering autopolyploidization-induced variations in two autotetraploid jujube cultivars and their diploid counterparts across morphological, cytological, and metabolic levels was conducted in the present study. Compared with the diploids, the autotetraploid jujubes exhibited larger leaves, flowers, and fruits, but a dwarfing phenotype with reduced fruit set. Additionally, decreased leaf stomatal density and weakened pollen viability were observed in the autotetraploid jujubes. Metabolomic analysis further revealed that autotetraploid fruits accumulated higher contents of soluble sugars, flavonoids, phenolics, and alkaloids but contained lower contents of amino acids. Based on LC-MS/MS quantification of leaf phytohormones, we identified six common hormones that were differentially accumulated in both cultivar comparisons. Notably, all six showed consistent alteration patterns between the two autotetraploid-diploid pairs. Together, these findings enhance our understanding of how autopolyploidy influences secondary metabolism, plant architecture, and hormone homeostasis in woody plants.