Contribution of plant-derived carbon to soil microbial biomass dynamics in a paddy rice microcosm
Contribution of plant-derived carbon to soil microbial biomass dynamics in a paddy rice microcosm
复制标题
DOI：
10.1007/s00374-002-0504-2
复制
发表时间：
2002-09-01
影响因子：
6.5
通讯作者：
Kimura, M
中科院分区：
文献类型：
--
作者：
Lu, YH;Watanabe, A;Kimura, M
了解稻田微生物生物量动态对管理其养分和碳循环至关重要。我们的目的是确定微生物生物量C （MBC）的季节动态是否与水稻根系中有机物质的释放有关。通过盆栽试验，测定了不同生育期水稻土壤溶液中MBC和溶解有机碳（DOC）的含量。在水稻不同生育期进行C-13脉冲标记（通过向水稻植株提供(CO2)-C-13 6 h），以估计光合作用的C对MBC的贡献。DOC浓度随植株生长而增加，反映了水稻根系中可溶性根系分泌物的释放。MBC在前期呈下降趋势，在水稻分蘖期至抽穗期迅速上升。在此增长期，MBC与DOC浓度和根系生物量呈显著正相关。约0.15-0.94%（平均0.54%）光合后的C-13在脉冲标记后立即被纳入MBC， 0.18-0.75%（平均0.41%）在季末仍被纳入MBC。估计光合产物对MBC的总贡献为91 mg C植株（-1），相当于季末总MBC的28%，或比生长季增加100%。结果表明，水稻土壤的MBC动态在很大程度上受水稻根系释放的有机物质的控制。
An understanding of the microbial biomass dynamics in rice paddies is essential for managing their nutrient and C cycling. Our objectives were to determine whether the seasonal dynamics of microbial biomass C (MBC) was related to the release of organic substance from rice roots. MBC and the dissolved organic C (DOC) in soil solutions were measured over a growing period of rice plants in a pot experiment. The C-13 pulse labelling (through supplying rice plants with (CO2)-C-13 for 6 h) was performed at different growth stages of rice to estimate the contribution of photosynthesized C to MBC. DOC concentrations increased with plant growth, reflecting the release of soluble root exudates from rice roots. MBC declined in the early period, and then rapidly increased from the maximum tillering stage to the heading stage of rice. During this period of increase, MBC was positively correlated to the DOC concentration and root biomass. About 0.15-0.94% (mean 0.54%) of photosynthesized C-13 was incorporated into MBC immediately after pulse labelling, and 0.18-0.75% (mean 0.41%) still remained at the end of the season. The estimated total contribution of photosynthates to MBC amounted to 91 mg C plant(-1), corresponding to 28% of total MBC at the end of the season or a 100% increase in MBC over the growing season. The results suggest that MBC dynamics in rice soil are largely controlled by organic substances released from rice roots.