| 要旨トップ | 目次 | 日本生態学会第59回全国大会 (2012年3月,大津) 講演要旨
ESJ59/EAFES5 Abstract


一般講演(ポスター発表) P2-371A (Poster presentation)

Is variation of soil respiration linked to diurnal patterns of photosynthesis? : Carbon partitioning by 13C pulse labeling

*Makita, N., Kosugi, Y.(Kyoto Univ.), Takanashi, S.(FFPRI)

Soil respiration in forest ecosystems plays a key role in the assessment of the net ecosystem C balance. Photosynthetic activity supplying carbohydrates from leaves to roots is an important driver of soil respiration. However, the immediate direct linkage between above- and below-ground is still uncertain. Here, we studied the effects of assimilated C supply on the diurnal pattern of soil respiration and its C isotope value (δ13C).

A pulse-labelling experiment was carried out in three Quercus serrata seedlings during the period of peak biomass. The δ13C of soil respiration was monitored at a high time resolution with an open dynamic chamber system using a cavity ring-down isotope CO2 analyzer (Picarro Inc.).

The time lag between C assimilation and soil respiration to the first high peak ranged from 23 to 26 hours after labeling. The δ13C of soil respiration showed a diurnal pattern, exhibiting significantly higher δ13C values during the morning time relative to those during the night time. Also, after the first high peak, the δ13C value decreased as time goes by, keeping the diurnal pattern. The variability of δ13C was correlated with the PAR and soil temperature. These results indicated that the respiratory utilization might be determined by the availability and inflow of assimilated C from leaves. We will discuss in more detail soil-plant-atmosphere continuum.


日本生態学会