Investigation of photosynthate-C allocation 27 days after ¹³C-pulse labeling of Zea mays L. at different growth stages

• Published in: Plant and soil 2013-12, Vol.373 (1-2), p.755-764
• Main Authors: Meng, Fanqiao, Dungait, Jennifer A. J, Zhang, Xuan, He, Minyi, Guo, Yanbin, Wu, Wenliang
• Format: Article
• Language: English
• Subjects: Acid soils; Agricultural soils; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Biological and medical sciences; biomass; Biomedical and Life Sciences; carbon; Chemical, physicochemical, biochemical and biological properties; Corn; crops; developmental stages; Ecology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; growing season; heading; Life Sciences; monitoring; Organic matter; Organic soils; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Plant Physiology; Plant Sciences; Plants; Regular Article; Rhizosphere; shoots; soil; Soil biochemistry; Soil organic carbon; Soil respiration; Soil science; Soil Science & Conservation; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Wheat soils; Zea mays
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-013-1841-7

AIMS: Pulse labeling of crops using ¹³C is often employed to trace photosynthesized carbon (C) within crop-soil systems. However, few studies have compared the C distribution for different labeling periods. The overall aim of this study was to determine the length of the monitoring interval required after ¹³C-pulse labeling to quantify photosynthate C allocation into plant, soil and rhizosphere respiration pools for the entire growing season of maize (Zea mays L.). METHODS: Pot grown maize was pulse-labeled with ¹³CO₂ (98 at. %) at the beginning of emergence, elongation, heading and grainfilling growth stages. The routing of ¹³C into shoot and root biomass, soil CO₂ flux and soil organic carbon (SOC) pools was monitored for 27 days after ¹³C-pulse labeling at the beginning of each growth stage. RESULTS: The majority of the ¹³C was recovered after 27 d in the maize shoots, i.e., 57 %, 53 %, 70 % and 80 %, at the emergence, elongation, heading, and grainfilling stages, respectively. More ¹³C was recovered in the root biomass at elongation (27 %) compared to the least at the grainfilling stage (3 %). The amount recovered in the soil was the smallest pool of ¹³C at emergence (2.3 %), elongation (3.8 %), heading and grainfilling (less than 2 %). The amount of ¹³C recovered in rhizosphere respiration, i.e. ¹³CO₂, was greatest at emergence (26 %), and similar at the elongation, heading and grainfilling stages (~16 %). CONCLUSIONS: At least 24 days is required to effectively monitor the recovery of ¹³C after pulse labeling with ¹³CO₂ for maize in plant and soil pools. The recovery of ¹³C differed between growth stages and corresponded to the changing metabolic requirements of the plant, which indicated labeling for the entire growth season would more accurately quantify the C budget in plant-soil system.