Dual-labeling with 15N and H218O to investigate water and N uptake of wheat under different water regimes
Background and aims
Water and nitrogen are essential for plant growth and yield. Plants depend on surface roots for nutrient uptake, but frequently rely on deep root systems for water uptake, especially in semi-arid, rain fed crop production systems.
We used H218O and 15NH4+ tracers in pots to determine water and NH4+ uptake at depth by two wheat genotypes watered from the surface or from the bottom. Root traits and transpiration rates were related to water and NH4+ uptake.
We observed a significant positive relationship between transpiration rate and water uptake measured by H218O tracer (R2 = 0.91), confirming that the H218O tracer method was successful. Surface soil drying (bottom watering) decreased both water and NH4+ uptake from the top soil. However, increased water availability with bottom watering increased water uptake from the bottom soil layer, but not NH4+ uptake from the bottom soil layer. Water uptake was positively related to total root length, while NH4+ uptake was positively related to root biomass.
With surface soil drying, plants grew more and longer roots in the bottom soil layer, shifting water uptake from the top to the bottom soil, while N uptake was reduced in the top soil because of a decrease in root biomass. Different root traits need to be considered when optimizing water and NH4+ uptake by wheat in water deficient seasons.
Keywords15N tracer H218O tracer NH4+ uptake Root traits Surface soil drying Transpiration rate Water uptake
- Chapin FS, Matson PA, Mooney HA (2002) Terrestrial nutrient cycling. Principles of Terrestrial Ecosystem Ecology. Springer, pp 197–223.Google Scholar
- Corneo PE, Suenaga H, Kertesz MA, Dijkstra FA (2016) Effect of twenty four wheat genotypes on soil biochemical and microbial properties. Plant Soil. doi:10.1007/s11104-016-2833-1
- Ehleringer JR, Evans RD, Williams D (1998) Assessing sensitivity to change in desert ecosystems—a stable isotope approach. In: Griffiths H (ed) Stable isotopes: integration of biological, ecological and geochemical processes. BIOS Scientific, Oxford, pp. 223–237Google Scholar
- IPCC (2013) In: Stocker T, Qin D, Plattner G, Tignor M, Allen S, Boschung J, Nauels a, Xia Y, Bex B, Midgley B (eds) Climate change 2007: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. UK & New York, NY, USA, Cambridge University Press, CambridgeGoogle Scholar
- Nagel KA, Bonnett D, Furbank R, Walter A, Schurr U, Watt M (2015) Simultaneous effects of leaf irradiance and soil moisture on growth and root system architecture of novel wheat genotypes: implications for phenotyping. J Exp Bot 66(18):5441–5452. doi:10.1093/jxb/erv290 PubMedPubMedCentralCrossRefGoogle Scholar
- Stark JM (2000) Nutrient transformations. In: Jackson RB, Mooney HA, Howarth RW (eds) Sala OE. Methods in Ecosystem Science, Springer New York, pp. 215–234Google Scholar
- Wang C, Liu W, Li Q, Ma D, Lu H, Feng W, Xie Y, Zhu Y, Guo T (2014) Effects of different irrigation and nitrogen regimes on root growth and its correlation with above-ground plant parts in high-yielding wheat under field conditions. Field Crop Res 165:138–149. doi:10.1016/j.fcr.2014.04.011 CrossRefGoogle Scholar