Table S1 Hydrogen isotope compositions of modern plant leaf wax C29 n-alkane (‰, relative to Standard Mean Ocean Water (SMOW))

Species / Location / Latitude(N) / Longitude(E) / Family / Class / Photosynthetic
pathway / Plant life forms / δD of C29
n-alkane(‰)
Bothriochloa ischaemum / Lantian / 34°14′ / 109°7′ / Gramineae / Monocotyledoneae / C4 / Grass / –207
Stipa bungeana / Lantian / 34°14′ / 109°7′ / Gramineae / Monocotyledoneae / C3 / Grass / –222
Artemisia princeps / Lantian / 34°14′ / 109°7′ / Compositae / Dictyledoneae / –– / Grass / –224
Agropyron cristatum / Lantian / 34°14′ / 109°7′ / Gramineae / Monocotyledoneae / C3 / Grass / –185
Lespedeza davurica / Lantian / 34°14′ / 109°7′ / –– / –– / C3 / Shrub / –172
Cirsium shansiense / Lantian / 34°14′ / 109°7′ / Compositae / Dictyledoneae / –– / Shrub / –158
Populus adenopoda / Lantian / 34°14′ / 109°7′ / Salicaceae / Dictyledoneae / C3 / Tree / –161
Unidentified / Lantian / 34°14′ / 109°7′ / –– / –– / C3 / Tree / –172
Cirsium japonicum / Xi’an / 34°20′ / 108°57′ / Compositae / Dictyledoneae / –– / Grass / –173
Lolium perenne / Xi’an / 34°20′ / 108°57′ / Gramineae / Monocotyledoneae / –– / Grass / –182
Agrostis clavata / Xi’an / 34°20′ / 108°57′ / Gramineae / Monocotyledoneae / –– / Grass / –179
Potentilla kleiniana / Xi’an / 34°20′ / 108°57′ / Rosaceae / Dictyledoneae / C3 / Grass / –156
Buddleja alternifolia / Xi’an / 34°20′ / 108°57′ / Buddlejaceae / Dictyledoneae / C3 / Shrub / –159
Ligustrum compactum / Xi’an / 34°20′ / 108°57′ / Oleaceae / Dictyledoneae / C3 / Shrub / –164
Cornus macrophylla / Xi’an / 34°20′ / 108°57′ / –– / Dictyledoneae / C3 / Tree / –169
Metasequoia glyptostroboides / Xi’an / 34°20′ / 108°57′ / Taxodiacceae / Gymnosperm / C3 / Tree / –143
Ginkgo biloba / Xi’an / 34°20′ / 108°57′ / Ginkgoaceae / Gymnosperm / C3 / Tree / –133
Cerasus yedoensis / Xi’an / 34°20′ / 108°57′ / Rosaceae / Dictyledoneae / C3 / Tree / –173

Table S2 Hydrogen isotope values of leaf water, soil water, and leaf wax n-alkane and corresponding fractionation values (‰)

Leaf water / Leaf wax / Soil water / ε(wax-SW) / ∆D(SW-LW)
Grass / Tree / Grass / Tree / Grass / Tree / Grass / Tree / Grass / Tree
–40 / –207 / –63 / –60 / –144 / 36
–24 / –224 / –79 / –80 / –163 / 53
–23 / –222 / –83 / –77 / –161 / 54
–35 / –185 / –75 / –76 / –121 / 41
–90 / –84
–30 / –172 / –83 / –76 / –106 / 48
–38 / –154 / –79 / –78 / –86 / 39
–47 / –157 / –81 / –80 / –89 / 30
–38 / –161 / –79 / –79 / –94 / 39
–47 / –150 / –70 / –76 / –82 / 30
–34 / –156 / –63 / –72 / –88 / 43
–36 / –172 / –66 / –67 / –106 / 41
–40 / –176 / –71 / –74 / 36
–64 / –80
–73 / –60
–67 / –75
–69 / –65
–70
–62