作 者 ：杨兰芳,蔡祖聪,祁士华
期 刊 ：生态学报 2007年 27卷 3期 页码：1072~1078
Keywords:maize growth, photosynthesis, soil respiration, δ13C,
摘 要 ：在玉米盆栽试验期间，运用碱吸收法采集土壤呼吸样品，转化成碳酸钡后，运用质谱法测定其δ13C值，以研究玉米生长和光合作用对土壤呼吸δ13C值的影响。结果表明，在玉米生长下，土壤呼吸的δ13C值随玉米生长时期而变化，变化在-14.57‰～-12.30‰之间，呈喇叭期>成熟期>开花期，而在裸土下，土壤呼吸的δ13C值在-19.34‰～-19.13‰之间，不随时间发生显著变化。开花期土壤呼吸δ13C值降低的主要原因是光合产物土壤输入的下降和根系活性的降低，成熟期玉米土壤呼吸δ13C值的增加主要是由于衰老死亡根系的分解腐烂。玉米生长下，无论开花期还是成熟期，白天土壤呼吸的δ13C值显著大于夜间；玉米植株遮光处理后，土壤呼吸的δ13C值显著降低。该试验结果证明玉米生长和光合作用显著影响土壤呼吸的δ13C值，在玉米生长期间，土壤呼吸主要来自于新近合成的光合产物。
Abstract:As a safe, stable and practical labelling method, the natural abundance of 13C has being widely used in the carbon cycle in soil-plant system. In order to investigate the effects of maize growth and photosynthesis on the value of δ13C in soil respiration, the value of δ13C in soil respiration was determined by mass spectrum after being trapped in a NaOH solution under a closed static chamber and then turned into barium carbonate in a pot experiment. The results showed that maize growth and photosynthesis significantly affected the value of δ13C in the soil respiration. In maize-planted soil, the value of δ13C in soil respiration had a clear seasonal variation. It changed with maize growth in the range of -14.57‰ to -12.30‰ and decreased during the period of trumpeting>ripening>flowering stages. The difference of δ13C in soil respiration during various maize growth stages added up to about 2.3‰. However, in bare soil, δ13C in soil respiration ranged from -19.34‰ to -19.13‰ and did not change significantly over time. The δ13C in soil respiration in maize-planted soil was lowest at flowering stage. This was mainly due to the decline of the input in assimilates into soil and the decrease in root activity. However, the δ13C increased at ripening stage, due to the decomposition and ingestion of senescent and died roots by soil microorganisms. In planted soil, δ13C in soil respiration was significantly higher during daytime than at nighttime at flowering and ripening stage. The difference of δ13C in soil respiration between day and night periods added up to about 1.4‰ and 2.1‰ during flowering and ripening stage, respectively. Shading maize plants at the trumpeting stage decreased the value of δ13C in soil respiration significantly. The difference of δ13C in soil respiration between the treatment of non-shading and shading plants added up to 2.85‰. It was conclude that δ13C in soil respiration was remarkably controlled by maize growth and photosynthesis in planted soil. Soil respiration was mainly derived from the recent assimilates during maize growth.