| 13CO2示踪臭氧胁迫对水稻土壤微生物的影响 |
| 摘要点击 1649 全文点击 985 投稿时间：2014-02-13 修订日期：2014-04-09 |
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| 中文关键词 臭氧 水稻 土壤微生物 13C同位素 13C-PLFA |
| 英文关键词 ozone rice soil microbe 13C isotope 13C-PLFA |
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| 中文摘要 |
| 本研究采用具有日变化的熏蒸方式，利用13C同位素示踪方法，结合PLFA技术，模拟分析了臭氧浓度升高对水稻土壤微生物结构的影响. 实验设置2个臭氧浓度处理，即空气对照（CF，臭氧浓度约4~10 nL ·L-1），臭氧浓度升高处理（O3，8 h平均浓度为110 nL ·L-1）. 分别在水稻熏气1个月和2个月时进行13C同位素标记实验. 结果发现，臭氧熏蒸一个月的时候对土壤微生物生物量碳没有影响，但此时输入到土壤微生物的即时光合产物13C已经显著低于对照；随臭氧熏蒸时间的延长，无论是总的土壤微生物量碳还是即时光合产物13C对土壤微生物的输入都显著低于对照处理. PLFA主成分分析结果表明，熏蒸一个月时臭氧对13C-PLFA的结构组成并没有显著影响，但熏蒸两个月后则臭氧明显改变了13C-PLFA的组成，但两次标记后PLFA单体的Δδ13C ‰值已受到臭氧的影响. 臭氧胁迫前期，只有细菌脂肪酸的13C分配（13C%）受到臭氧的明显影响，而胁迫后期则臭氧主要影响的是分配给放线菌和真菌的13C. |
| 英文摘要 |
| This study was initiated to explore the effects of dynamic ozone (O3) exposure on soil microbial biomass and phospholipid fatty acids (PLFAs) under potted rice. A pulse-chase labeling experiment was designed to expose potted rice with 13CO2 for 6 h after one and two months, the rice were fumigated by elevated O3 concentration with an 8 h mean of 110 nL ·L-1 (O3). The allocation of the assimilated 13C to soil microorganisms was estimated by analyzing the 13C profile of microbial phospholipid fatty acids (PLFAs). After one month O3 exposure, the soil microbial biomass carbon was not affected, while the 13C-microbial biomass was significantly decreased with elevated O3. Both the total and 13C microbial biomass carbon was remarkably lower than that of control treatment after two months O3 exposure. Principal components analysis of 13C-PLFA data showed that elevated O3 significantly changed soil microbial structure after two month exposures, while there was no difference of 13C-PLFA structure between control and elevated O3 treatments after one month exposure. Δδ13C ‰ of individual PLFA was significantly affected by O3 after both one and two month exposures. Only did ozone change the relative abundance of individual 13C-PLFA (13C%) of bacterial fatty acids after one month exposure, while after two month exposures, the 13C% of fungal and actinomycetic fatty acids were markedly changed by elevated O3. |
