【摘要】 土壤有机碳库作为陆地生态系统最大的碳库,其微小的变动就能影响着全球碳的平衡、生物多样性、土壤养分状况以及整个生态系统的可持续发展。其中,植物光合作用是陆地和大气间碳循环的驱动力,是土壤有机碳的重要来源。自1979年中国引入互花米草（Spartina alterniflora）后,大面积的互花米草入侵必然对盐沼土壤有机碳的输入和输出、碳循环产生影响。研究互花米草生长期内光合碳的分配问题对湿地碳平衡具有重要意义。在互花米草生育期内通过盆栽实验对互花米草进行4次¹³C脉冲标记,研究互花米草光合碳在互花米草-土壤系统中各组分的分配及固定。结果表明:（1）标记互花米草¹³C丰度值明显增加,随标记次数增加呈上升趋势,各组分¹³C丰度值表现为茎>叶>根>根际土壤>土体;（2）互花米草各组分固定的¹³C量随标记次数增加而增加,4次标记固定的¹³C量在52.80-276.81mg·plant^-1（以C计）之间。互花米草各组分固定¹³C量呈现茎>叶>根>根际土壤>土体的趋势;（3）4次标记后互花米草-土壤系统各组分固定¹³C量占净光合¹³C总量分配比例呈现茎>叶>根>根际土壤>土体的趋势,叶分配比例为32.48%-39.20%,茎分配比例为39.83%-47.65%,根分配比例为18.01%-20.34%,根际土壤分配比例为0.30%-0.42%,土体分配比例为0.08%-0.20%。光合碳在互花米草各部分以及土体中都有所增加,主要集中在地上部分。更多还原

【Abstract】 Soil organic carbon pools, the largest carbon pool of terrestrial ecosystems, can affect the balance of global nitrogen,biodiversity, soil nutrient status and the sustainable development of the entire ecosystem. Among them, plant photosynthesis is the driving force of carbon cycle between land and atmosphere. And it’s also an important source of soil organic carbon. Large-scale invasion of S. alterniflora which was introduced in China in 1979 had inevitably affected the input and output of organic carbon in salt marsh soil and carbon cycle. Studying the distribution of photosynthetic carbon during the growth period of S. alterniflora is significant for wetland carbon balance. ¹³C pulse-labelling method was used to estimate the photosynthesized carbon distribution and quantify the carbon inputs into each part in S. alterniflora-soil system during the growth period. The results revealed that:（1） the abundance of ¹³C value of S. alterniflora increased significantly. The ¹³C value occurred in the plant-soil system as the order of stem>leaf>root>rhizosphere soil>bulk soil.（2） The amount of ¹³C fixed by the S. alterniflora was 52.80-276.81 mg ·plant^-1（by C）with four times labeling. Fixed ¹³C increased along with the number of tags. The fixed ¹³C mainly concentrated in the aboveground parts of plant（stems and leafs） and presented as stems>leaf>root>rhizosphere soil>bulk soil. And（3） after four times labeling, the proportion of net fixed C of the components in plant-soil system presented as stem>leaf>root>rhizosphere soil>bulk soil. The proportion of net fixed ¹³C was 32.48%-39.20% in leaf; 39.83%-47.65% in stem; 18.01%-20.34% in root; 0.30%-0.42% in rhizosphere soil; 0.08%-0.20% in soil. The photosynthesized carbon in all parts of S. alterniflora and soil has increased. The photosynthetic carbon is mainly concentrated in the aboveground part.更多还原