Allocation of photosynthestically-fixed carbon in plant and soil during growth of reed (Phragmites australis) in two saline soils
- 610 Downloads
Terrestrial carbon (C) sequestration is derived mainly from plant photosysthetically-fixed C deposition but soil organic C (SOC) content in saline soils is generally low due to low deposition of C from restricted plant growth. It is important to explore the effects of soil salinity on the allocation of photosynthetically-fixed C to better understand C sequestration in saline wetland soils.
We conducted a pot experiment in which reed (Phragmites australis) was grown in a low salinity (LS) soil and a high salinity (HS) soil from the Yellow River Delta under flooded conditions. The allocation of photosynthetically-fixed C into plant tissues, SOC, dissolved organic C (DOC), microbial biomass C (MBC), particulate organic C (POC), and mineral-associated organic C (MAOC) was determined using a 13C pulse-labeling method after four labeling events during the 125-day-long reed growing season and destructive sampling immediately at the end of six hours of pulse labeling (end 6-h) and on the final harvest day (final day).
In most cases soil salinity, reed growth stage, or reed biomass significantly (P < 0.05) affected the deposition of photosynthetically-fixed C into the plant-soil system. At all four pulses at end 6-h the high salinity soil had significantly (P < 0.05) lower percentage net assimilated 13C in the roots and significantly higher (P < 0.05) percentage net assimilated 13C in the soil than did the low salinity soil. At both end 6-h and on the final day the high salinity soil had significantly (P < 0.05) lower SO13C, and significantly (P < 0.05) higher DO13C/SO13C ratio than the low salinity soil except for pulses 3 and 4 on the final day. The majority of photosynthetically-fixed C in soil was deposited into MAOC pools and >80 % of deposited SO13C was present as MAOC in the high salinity soil due to its significantly (P < 0.05) higher clay content compared with the low salinity soil.
Soil salinity affected the allocation of photosynthetically-fixed C in the plant-soil system, and soil texture altered the allocation of rhizodeposition C in different soil particles.
KeywordsSoil salinity Soil organic C pools Photosynthetically-fixed C 13C pulse labeling Flooded pot experiment
This work was funded by the National Natural Science Foundation of China (41101220), the Outstanding Young Scientist Research Award Fund of Shandong Province, China (BS2011HZ001), the “973” program (2013CB127405), and National Nonprofit Institute Research Grant of CAAS (IARRP-2015-27).
- FAO (2002) Key to the FAO soil units in the FAO/Unesco soil map of the world. Available at www.fao.org/ag/agl/agll/key2soil.stm (verified 17 Nov. 2011). FAO, Rome
- González-Alcaraz MN, Egea C, Jiménez-Cárceles FJ, Párraga I, María-Cervantes A, Delgado MJ, Álvarez-Rogel J (2012) Storage of organic carbon, nitrogen and phosphorus in the soil-plant system of Phragmites australis stands from a eutrophicated Mediterranean salt marsh. Geoderma 185–186:61–67CrossRefGoogle Scholar
- Jenkinson DS (1988) Determination of microbial biomass carbon and nitrogen in soil. In: Wilson JR (ed) Advances in nitrogen cycling in agricultural ecosystems. CAB International, Wallingford, UK, pp. 368–386Google Scholar
- Wang W, Liu J, Zhang B, Zhang J, Li X, Y Y (2015) Critical evaluation of particle size distribution models using soil data obtained with a laser diffraction method. Soil Sci 178: 194–204Google Scholar