中文关键词水稻光合碳拔节期施氮¹³C脉冲标记根际非根际 英文关键词rice photosynthesized carbonjointing stagenitrogen application¹³C pulse-labelingrhizospherebulk

作者	单位	E-mail
陈珊	中南林业科技大学环境科学与工程学院, 长沙 410004 中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125	869283723@qq.com
祝贞科	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
袁红朝	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
王久荣	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
彭佩钦	中南林业科技大学环境科学与工程学院, 长沙 410004	pqpeng123@sina.com
葛体达	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
吴金水	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125

中文摘要 水稻光合碳是稻田土壤有机碳的重要来源之一，其在土壤中输入与分配特征受水稻生长状况和土壤肥力的影响.施肥是影响水稻生长的关键因素，为了探讨施氮对水稻拔节期光合碳的传输动态的影响，应用稳定同位素¹³C-CO₂脉冲标记技术，通过盆栽试验，研究光合碳在水稻-（根际/非根际）土壤系统中输入与分配的动态变化及其对施氮的响应.结果表明，施氮显著增加了水稻地上部和根系生物量，降低了水稻根冠比.随着水稻的生长，水稻植株的¹³C丰度逐渐下降，根际土和非根际土中¹³C丰度先减少再增加；施氮显著增加了根际土壤中¹³C丰度，较不施氮相比增加了9.5%~32.6%.施氮使水稻地上部和根系中光合¹³C含量显著增加，较不施氮处理分别增加了24.5%~134.7%和9.1%~106%.脉冲标记一次性输入的光合¹³C主要分配在水稻植株体内，不施氮和施氮条件下的分配率分别为85.5%~93.2%和91.3%~95.7%；施氮显著影响光合碳在水稻地上部、根际土和非根际土中的分配特征（P<0.01），标记后26 d，与不施氮处理相比，施氮使光合碳在水稻地上部的分配增加了13.4%，在根际土和非根际土中的分配分别减少了21.9%和52.2%.因此，施氮增加了光合碳在土壤-水稻系统中的分配，但降低了光合碳在土壤中的累积.本研究进一步探讨了施氮条件下水稻拔节期光合碳的分配，为明确氮素对光合碳在水稻拔节期的动态变化以及对土壤有机碳库的影响，和深入了解农田土壤有机质累积提供理论依据和数据支持. 英文摘要 Photosynthesized carbon (C) is an important source of soil organic C in paddy fields, and its input and distribution are affected by rice growth and soil fertility. Fertilizer application plays an important role in rice growth. The ¹³C pulse-labeling method was used to quantify the dynamics and distribution of input photosynthesized C in the rice-(rhizosphere-and bulk-) soil system and its response to nitrogen fertilizer (N) application. The results suggested that N fertilization significantly increased the rice aboveground and the root biomass and decreased the rice biomass root/shoot ratio. The amount of assimilated ¹³C gradually decreased in the rice plants but gradually decreased over 0-6 days and increased over 6-26 days in the rhizosphere and bulk soil during rice growth. N fertilization significantly increased the amount of assimilated ¹³C in the rhizosphere soil by 9.5%-32.6% compared with the control. In comparison to the unfertilized treatment, the application of N fertilization resulted in higher photosynthetic¹³C in rice aboveground and in the root by 24.5%-134.7% and 9.1%-106%, respectively. With the N fertilized and unfertilized treatments, 85.5%-93.2% and 91.3%-95.7%, respectively, of input photosynthetic ¹³C was distributed in the rice plants. The results suggested that N fertilization significantly affected the distribution of photosynthesized C in the rice-soil system (P<0.01). After 26 days of pulse labeling, the distribution of photosynthetic ¹³C into rice aboveground was increased by 13.4%, while the distribution into the rhizosphere and bulk soil were decreased by 21.9% and 52.2%, respectively, in the N fertilized treatments compared with the unfertilized treatments. Therefore, the N application increased the distribution of photosynthesized carbon in the soil-rice system but decreased the accumulation in the rhizosphere and bulk soil. The findings of this study provided a theoretical basis for our understanding of the dynamic of photosynthetic C in the plant-soil system and the assimilation of the soil organic matter pool in the paddy soil ecosystem.

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