RESUMO
With the Quanfuzhuang River basin located at Hani Rice Terrace core region as study area, we analyzed the isotopic composition and the effects of 12 surface water sampling sites for the forest landscape type and terrace landscape type from May 2015 to April 2016. The results showed that: 1) For the variation of isotope composition, both the average value and the variation range of δ18O in surface water under forest patches were smaller than that under terrace patches. 2) The overall elevation effect of the hydrogen and oxygen stable isotopes in surface water was obvious, except that in August and March, which could be expressed as the linear regression equation δ18O=-0.012H+13.84 (r=-0.83, n=12). 3) The altitude gradient of δ18O in surface water was -1.2·(100 m)-1, which was not the true altitude gradient affected by precipitation but by landscape gradient of δ18O in surface water between forest patches and terrace patches. 4) Under the "Forest-Terrace" landscape pattern, the δ18O differences in surface water between forest patches and terrace patches enhanced the elevation effect. Therefore, when landscape heterogeneity was strong, isotopic effect was strengthened, even with opposite isotope effect.
Assuntos
Oryza , Água , Hidrogênio , Isótopos de Oxigênio/análise , RiosRESUMO
Analysis of hydrogen and oxygen stable isotopes is an effective method to track the water cycle in watershed. Impact of landscape pattern on the isotope effects of spring water is a new interdisciplinary topic between landscape ecology and isotope hydrology. Taking the Quanfuzhuang River basin located in the core area of UNESCO World Cultural Heritage of Honghe Hani Rice Terrace as the object, collecting the monthly samples of 78 points of spring water and 39 precipitation at altitude of 1500 m (terraces), 1700 m (terraces) and 1900 m (forest) from March 2015 to March 2016, we analyzed the hydrogen and oxygen stable isotopes of water samples under the different landscape types. The results indicated that the dominated landscape types were forests and rice terraces, being 66.6% and 22.1% of the whole landscape area respectively, and they had a spatial vertical pattern of forest located at the mountain top and rice terraces at the down-slope. The correlation analysis showed that the spring water not only came from the precipitation, but also from other water sources which had a more positive δ18O and δD values, the spring water in up-slope forests mainly came from precipitation, while that in down-slope rice terraces came from precipitation, ri-ver water, rice terrace water and under ground water. Therefore, the mixing effects of spring water δ18O and δD were more significant in rice terraces. The overall altitude effect of the hydrogen and oxygen stable isotopes in spring water was obvious. The linear decreasing rates of δ18O and δD values were -0.125·(100 m)-1and -0.688·(100 m)-1, respectively. The deuterium surplus value increased with the altitude because of the impacts of landscape pattern and the local cycle of water isotopes. In summary, the dominant landscape types had a significant impact on the hydrogen and oxygen isotopes of spring water, which could be used as response indicator to reveal the impacts of landscape pattern on hydrological process.
Assuntos
Hidrogênio , Oryza , Isótopos de Oxigênio , Deutério , Monitoramento Ambiental , ÁguaRESUMO
OBJECTIVE: To establish a rapid analytical method for furan components before and after processing of Polygonatum rhizome by static headspace injection GC-MS. METHODS: The volatile components were extracted by headspace injection technique and analyzed by GC-MS, and the furan components of three species of Polygonatum rhizome before and after processing were determined by semi quantitative GC-MS. RESULTS: Three species of Polygonatum rhizome had significant differences in furan components contents, Polygonatum cyrtonema ≈ Polygonatum kingianum > Polygonatum sibiricum. Each species of Polygonatum rhizome had a corresponding increase in almost all of the nine kinds of furan components after processing, steamed products > stewed products. CONCLUSION: This study provides a theoretical basis for further study of processing of Polygonatum rhizome.
