ESPAS — An advanced phytotron for measuring carbon dynamics in a whole plant-soil system

Abstract

The use of carbon isotopes as tracers is essential for measuring carbon flows in an intact whole plant-soil system. Here, we describe an Experimental Soil Plant Atmosphere System (ESPAS) to perform pulse-labelling and steadystate labelling experiments with 13CO2 and 14CO2. The ESPAS facility is an environmental research tool that is used to measure the carbon fluxes from the atmosphere to the roots and into the soil and the microbial biomass and to study decomposition of plant residues and soil organic matter. The influence of environmental conditions in the atmosphere or in soil on the carbon allocation and turnover in the plant-soil ecosystem can be quantified. The design and the technical description of the phytotrons is presented and evidence is provided that the phytotrons are equivalent. For this purpose, Triticum aestivum plants were cultivated in the phytotrons for 39 days and shoot growth, root growth and water use were compared. No significant differences were observed for plant growth and water use. As an example of the practical application of the equipment, an experiment with elevated atmospheric CO2 is presented. Data are given on the uptake of 14C under ambient (350 #L L -l) and elevated (700 #L L-ICO2 in Lolium perenne and Festuca arundinacea and the distribution of 14C among different plant-soil compartments i.e. shoot, root, root-soil respiration, and soil. We conclude that these phytotrons yield detailed information on gross carbon flows in a whole plant-soil system that can not be obtained without sensitive carbon tracers. Such data are important for proper calibration of simulation models on soil organic matter.

Passage of stable isotope-labeled grass silage fiber and fiber-bound protein through the gastrointestinal tract of dairy cows

“…The isotope-enriched internal markers were prepared as δ 13 C-and δ 15 N-labeled grass silage originating from the field that also provided the bulk grass silage. In brief, representative ryegrass shoots from the second regrowth were randomly collected from the field and grown on hydroponics (8.6 shoots/m 2 ) under climatecontrolled greenhouse conditions in hermetically sealed isotope assimilation chambers (IsoLife, Wageningen, the Netherlands), specifically designed for homogeneous atmospheric isotope-labeling (Gorissen et al, 1996). From plant emergence onwards, grass was continuously enriched under high levels of 13 CO 2 and by injecting plant pots with a K 15 NO 3 solution.…”

Assimilation dynamics of soil carbon and nitrogen by wheat roots and Collembola

“…The average temperature was 15.5 8C and the day length 17 h. The 13 C and 15 N enriched ryegrass was kindly provided by Plant Research International, Wageningen The Netherlands, and is henceforth referred to as Wageningen ryegrass. The ryegrass seedlings were grown for 35 days in a sandy loam soil fertilized with 79.6 mg NH 4 NO 3 containing 7.6 mg 15 NH 4 + in 0.65-L pots in growth chambers, in which a continuously 13 C-labelled atmosphere was maintained (Gorissen et al 1996). This setup ensured that all compounds in the labelled plant material were homogenously labelled.…”

Dark septate root endophytic fungi increase growth of Scots pine seedlings under elevated CO2 through enhanced nitrogen use efficiency

“…The Petri dishes were randomized every two weeks within each growth chamber. After 98 days, the treatments under ambient CO 2 were transferred to an Experimental Soil Plant Atmosphere System (ESPAS; Gorissen et al 1996) and treatments under elevated CO 2 to another ESPAS compartment. The ESPAS facility consists of closed and sealed growth chambers with controlled condition of light, humidity, temperature and CO 2 availability.…”