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

Abstract

Aims Pulse labeling of crops using 13 C 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 13 C-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 13 CO 2 (98 at.%) at the beginning of emergence, elongation, heading and grainfilling growth stages. The routing of 13 C into shoot and root biomass, soil CO 2 flux and soil organic carbon (SOC) pools was monitored for 27-days after 13 C-pulse labeling at the beginning of each growth stage. Results The majority of the 13 C 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 13 C 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 13 C at emergence (2.3 %), elongation (3.8 %), heading and grainfilling (less than 2 %). The amount of 13 C recovered in rhizosphere respiration, i.e. 13 CO 2 , 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 13 C after pulse labeling with 13 CO 2 for maize in plant and soil pools. The recovery of 13 C 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 plantsoil system.

Novel Approach for High-Throughput Metabolic Screening of Whole Plants by Stable Isotopes

“…4D), which is in the range of values reported for other plants (Leake et al, 2006). During development from flowering to late grain filling, the relative contribution of different leaves to carbon assimilation probably corresponds to changing metabolic requirements (Meng et al, 2013). During late grain filling, the lower activity of carbon assimilation in mature leaves, relative to the flag leaf, indicated mechanisms of senescence (Fig.…”

“…A catalog of experiments addressed this issue. Grain yield, the most prominent characteristic of crop plants, is strongly dependent on the source-sink relationship between plant parts (Kato et al, 2004), whereby the operational mode of a distinct plant organ, as source or sink, changes throughout development (Meng et al, 2013). Pioneering studies with rice plants, using radioactive 14 CO 2 at high dosage, had revealed the translocation of assimilated carbon into the panicle during grain filling (Cock and Yoshida, 1972).…”

“…A total of 76% of assimilated carbon was thus recovered inside the plant 2 h after assimilation, which indicated a loss of 24% via respiration. The retainment of carbon in the shoot was slightly higher than that for maize (Zea mays) plants, in which 53% of 13 C is recovered inside the shoot at elongation (Meng et al, 2013). The same calculation, using labeling data from samples taken 24 h after the pulse (i.e.…”

Photosynthate supply drives soil respiration of Fraxinus mandshurica seedlings in northeastern China: evidences from a shading and nitrogen addition experiment

“…The differences mainly derive from different vegetation types and stages of growing season. It is possible that the seasonal effect of shading on SR was due to the seasonality of photosynthesis (Wu et al 2012) and photosynthates allocation (Meng et al 2013). There were significant exponential relationships between SR and soil temperature among treatments (P \ 0.001) ( Table 1).…”

Bicarbonate stimulates non‐structural carbohydrate pools of Camptotheca acuminata

“…This starch is then degraded and converted to soluble sugars (mainly sucrose) to supply the plants with carbohydrates during the following night (Smith and Stitt , Zeeman et al ). Most studies only used 13 CO 2 labeling to track the partitioning of newly fixed C into different tissues (Meng et al , Bloemen et al , Li et al ). The pattern of soil DIC assimilation, with respect to post‐photosynthate allocation, should be similar to that of atmospheric CO 2 .…”