δ~(13)C and water-use efficiency indicated by δ~(13)C of different plant functional groups on Changbai Mountains, Northeast China

Leaf δ13C of different plant functional groups (trees, shrubs and forbs; evergreen and deciduous; annual, biennial and perennial) were examined on the Changbai Mountains, China. Life form has a significant influence on plant δ13C, suggesting that leaf δ13C is also ideal for distinguishing functional groups species in temperate and frigid zones with high humidity. Additionally, the difference of water-use efficiency (WUE) is significant among different plant functional groups. δ13C and WUE are in the followi...     

δ~(13)C difference between plants and soil organic matter along the eastern slope of Mount Gongga

Carbon isotope ratios (δ 13C) of plants, litter and soil organic matter (0–5 cm, 5–10 cm and 10–20 cm) on the eastern slope of Mount Gongga were measured. The results show that δ 13C values of plants, litter and soil organic matter all decrease first and then increase with altitude, i.e. δ 13C values gradually decrease from 1200 to 2100 m a.s.l., and increase from 2100 to 4500 m a.s.l. The δ 13C altitudinal variations are related to the distribution of C3 and C4 plants on the eastern slope of Mount Gongga, ...     

Magnetic fabric of early Quaternary loess-paleosols of Longdan Profile in Gansu Province and the reconstruction of the paleowind directions

The anisotropy of magnetic susceptibility （AMS） is a rapid and precise tool for determining paleowind directions. During the past several decades, AMS has been used for determining paleowind directions of Chinese loess. The AMS for a Ioess-paleosol profile in early Quaternary at Longdan in the Linxia Basin, Gansu Province, northeastern fringe of Qinghai-Xizang （Tibetan） Plateau has been obtained. The primary results show that the AMS of the Longdan profile has its typical normal eolian dust deposit. The AMS is mainly controlled by magnetic foliation （F） and the shape parameter of the AMS ellipsoid is oblate. The declination of maximum susceptibility （K1） was used to determine the paleowind direction of that area in early Quaternary and it was found that the paleowind direction is biased towards NW-SE.     

δ^13C and water-use efficiency indicated by δ^13C of different plant functional groups on Changbai Mountains,Northeast China

Leaf δ^13C of different plant functional groups （trees, shrubs and forbs; evergreen and deciduous; annual, biennial and perennial） were examined on the Changbai Mountains, China. Life form has a significant influence on plant δ^13C, suggesting that leaf δ^13C is also ideal for distinguishing functional groups species in temperate and frigid zones with high humidity. Additionally, the difference of water-use efficiency （WUE） is significant among different plant functional groups. δ^13C and WUE are in the following order of forbs 〈 shrubs 〈 trees. Within shrubs, δ^13C and WUE are higher for evergreen shrubs than deciduous shrubs. Differences in δ^13C and WUE are significant among different lifespan herbs, and δ^13C and WUE follow the order of annual herbs 〉 biennial herbs 〉 perennial herbs, not in accordance with the pattern obtained by previous studies in deserts, suggesting that the ranking of δ^13C and WUE among annual, biennial and perennial herbs may be dependent on local water availability.     

δ13C difference between plants and soil organic matter along the eastern slope of Mount Gongga

Carbon isotope ratios (δ¹³C) of plants, litter and soil organic matter (0–5 cm, 5–10 cm and 10–20 cm) on the eastern slope of Mount Gongga were measured. The results show that δ¹³C values of plants, litter and soil organic matter all decrease first and then increase with altitude, i.e δ¹³C values gradually decrease from 1200 to 2100 m a.s.l., and increase from 2100 to 4500 m a.s.l. The δ¹³C altitudinal variations are related to the distribution of C₃ and C₄ plants on the eastern slope of Mount Gongga, because C₄ plants are observed to grow only below 2100 m, while C3 plants occur at all altitudes. There are significantly positive correla-tions among δ¹³C of vegetation, δ¹³C of litter and δ¹³C of soil organic matter, and litter, 0–5 cm, 5–10 cm and 10–20 cm soil or-ganic matter are 0.56‰, 2.87‰, 3.04‰ and 3.49‰ greater in δ¹³C than vegetation, respectively. Considering the influences of rising concentration of atmospheric CO₂ and decreasing δ¹³C of atmospheric CO₂ since the industry revolution on δ¹³C of plants, 1.57‰ is proposed to be the smallest correction value for reconstruction of paleovegetation using δ¹³C of soil organic matter.