Leaf anatomical structure of dominant shrubs and their influencing factors across habitats in hyper-arid region.

We analyzed the drought adaptation mechanism of shrub species in three typical habitats (oasis, transition zone, and desert) of the extremely arid area in the lower reaches of the Heihe River, with 15 species as the objects. Using paraffin sectioning technology combined with microscopic observation, we measured 14 anatomical traits, including leaf epidermal thickness, total leaf thickness, palisade tissue thickness, spongy tissue thickness, and main vein vascular bundle thickness, etc. The results showed that leaf thickness, palisade tissue thickness, and leaf structure compactness (palisade tissue thickness/total leaf thickness) significantly varied among different habitats, and increased with the aggravation of drought degree.