Leaf Anatomical and Transcriptomic Coordination Underlies Drought Resilience in Psammophytes

Global climate change-induced precipitation reduction severely threatens the sustainability of sandy grassland ecosystems. Understanding the adaptive strategies of native psammophytes is crucial for desertification control. We integrated leaf anatomy and transcriptomics (RNA-seq/WGCNA) to decipher drought resistance in three dominant psammophytes from Horqin Sandy Grassland. The finding revealed that the C3 annual/biennial herb Artemisia scoparia exhibited the most robust transcriptomic response, with co-expression modules linking tyrosine metabolism to cuticular thickening; the C3 semi-shrub Lespedeza davurica showed superior anatomical adaptation, underpinned by phenylpropanoid biosynthesis, while the C4 perennial herb Cleistogenes squarrosa exhibited molecular signatures of high drought sensitivity, with severe drought disrupting its flavonoid biosynthesis and circadian rhythms. In this study, the C4 herbaceous species showed stronger precipitation dependence than the C3 herbs. Our study provides molecular-anatomical insights into the ecological restoration of sandy grasslands under global change, suggesting the use of shrubs as primary stabilizers for sand fixation, alongside breeding herbaceous genotypes with optimized anatomical and transcriptomic traits to meet the needs of sustainable vegetation recovery in sandy grasslands under climate change.