摘要
采用稳定同位素质谱仪Isoprime100,对采自黄河源区典型高寒草甸和人工改良草地的主要植物进行了碳、氮组成及其稳定同位素丰富度测定,判断植物光合类型,探讨稳定碳氮同位素丰富度对草地植被演替的响应。结果表明:(1)研究区58种主要植物碳元素含量在28.64%~51.55%之间,氮元素含量介于0.89%~4.04%,δ13 C值变化范围介于-29.50‰^-24.69‰,δ15 N值介于-4.57‰~8.32‰。(2)不同样地植物碳含量的大小顺序为人工草地(45.54%)>未退化草甸(43.18%)>轻度退化草甸(42.18%)>严重退化草甸(39.68%),氮元素含量顺序为未退化草甸(2.30%)>人工草地(2.28%)>轻度退化草甸(2.13%)>严重退化草甸(2.10%),表明草甸退化会引起植物碳氮含量的降低。(3)未退化草甸、人工草地、轻度退化草甸和严重退化草甸的δ13 C值依次为-25.63‰、-26.57‰、-26.76‰和-27.91‰,δ15 N值依次为-0.63‰、0.32‰、2.76‰和0.26‰。研究认为,黄河源区高寒草甸和人工改良草地的58种主要植物均属C3植物,没有发现C4和景天酸代谢(CAM)植物,低的年均气温可能是制约该区C4植物分布的主要因素;植物δ13 C值随草地退化程度加剧而逐渐降低,但δ15 N值的变化无规律性趋势。
The carbon and nitrogen composition and stable isotope abundance of plants collected from the alpine meadows and seeded pasture at the headwater region of the Yellow River were analyzed with mass spectrometer Isoprime100.The purpose was to determine the type of plant photosynthesis and response of carbon and nitrogen stable isotopes abundance to vegetation succession.The results show that：（1）plant carbon content of 58 species varies between 28.64% and 51.55% and nitrogen content is from 0.89% to4.04%.Theδ13C abundance varies between-29.50‰and-24.69‰and theδ15 N value is from-4.57‰to 8.32‰.（2）The plant carbon content of different sites is in the order of mix-seeded pasture（45.54%）non-degraded meadow（43.18%）〉light degraded meadow（42.18%）〉heavily degraded meadow（39.68%）.The plant nitrogen content of different sites is in the order of non-degraded meadow（2.30%）〉mix-seeded pasture（2.28%）light degraded meadow（2.13%）〉heavily degraded meadow（2.10%）.（3）Theδ13 C values of plants in mix-seeded pasture,non-degraded meadow,light degraded meadow and heavily degraded meadow are-25.63‰,-26.57‰,-26.76‰ and-27.91‰,respectively,and theδ15 N values are-0.63‰,0.32‰,2.76‰ and 0.26‰,respectively.Alpine degradation can result in decreased plant carbonand nitrogen content.All species analyzed are C3 plants and no C4 and Crassulacean acid metabolism（CAM）plants were found.The low annual mean temperature may be the main factor restraining the distribution of C4 plants.Theδ13C values decrease with degradation,but theδ15 N values have no such tread.
出处
《西北植物学报》
CAS
CSCD
北大核心
2015年第8期1650-1656,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(31260573)
青海省科技厅国际合作项目(2012-H-806)
教育部创新团队(IRT13074)
教育部美大项目(2014)
关键词
高寒草甸
稳定同位素
碳氮成分
黄河源区
alpine meadow
stable isotope
carbon and nitrogen
headwaters of Yellow River
