Central Experimental Platform
Two substrates differing in texture have been selected for the central experimental platform (SPE, SCEs), a loam (L ) and a sand (S). The loam is derived from the 0 to 50 cm depth of a Haplic Phaeozem close to Schladebach in Saxony Anhalt. The sand is a mixture of 16.7% loam and 87.3% quartz sand (WF33, Quarzwerke GmbH). Through this procedure both substrates are inoculated with the same microbiome and share to some extent the composition of soil minerals and organic matter although amounts differ. Their characteristics are summarized in Table 1.
| Origin | Haplic Phaeozem |
83.3% Sand 16.7% Haplic Phaeozem |
| Substrate properties | Loam (L) | Sand (S) |
| Ct [g kg-1] | 8.5 | 1.5 |
| Nt [g kg-1] | 0.8 | 0.2 |
| pH (CaCl2) | 6.4 | 6.3 |
| Nmin [mg kg-1] | 1.4 | 0.3 |
| Pavailable [mg kg-1] | 32.7 | 8.3 |
| Kavailable [mg kg-1] | 28.5 | 7.8 |
| Texture (sand/silt/clay) | 33/48/19 | 92/5/3 |
| Carbonate [%] | 0.0 | 0.0 |
| Bulk density | 1.39 | 1.49 |
Two Zea mays genotypes will be compared; the wildtype and the rth3 mutant.
rth3 mutant:
Zea mays mutant with normal root hair initiation but disturbed elongation. The mutant, first described by Wen & Schnable (1994) shows no apparent aberrant shoot phenotype, but yield is reduced by 20 to 40 % compared to the wildtype (Hochholdinger et al. 2008). When grown under field conditions less soil adheres to the root system. The mutant phenotype remains stable under field conditions.
Hochholdinger F, Wen T-J, Zimmermann R, Chimot-Marolle P, da Costa e Silva O, Bruce W, Lamkey KR, Wienand U, Schnabel PS (2008) The maize (Zea mays L.) roothairless3 gene encodes a putative GPI-anchord, monocot-specific, COBRA-like protein that significantly affects grain yield. The Plant J 54, 888-898.
Wen T-J, Schnable PS (1994) Analyses of mutants of three genes that influence root hair development in Zea mays (Gramineae) suggest that root hairs are dispensable. American Journal of Botany 81, 833-842.
Li L., Hey S., Liu S., Liu Q., McNinch C., Hu H.C., Wen T.J., Marcon C., Paschold A., Bruce W., Schnable P.S., Hochholdinger F. (2016) Characterization of maize roothairless6 which encodes a D-type cellulose synthase and controls the switch from bulge formation to tip growth. Sci. Rep. 6, 34395.
Soil plot experiments (SPE) was established in October 2018 with the same treatments (2 genotypes x 2 textures) as for SCE at the experimental station of the Helmholtz Centre for Environmental Research in Bad Lauchstädt. The Soil plot experiments consist of 24 plots with an individual plot size of 11x3.1 meters. The substrates were excavated at the original sites (see soils), homogenized and disposed on a drainage layer with a thickness of 75 cm. Plants were grown for the first field season in 2019. Maize plants will be grown up to maturity in a randomized block design each season, for six consecutive years. From harvest to next seeding soil is kept fallow (compare H1, H2, H4).
I. This enables in comparison to SCE measurements at later time points avoiding artefacts created by volume restriction,- Destructive sampling maintaining spatial context (i.g. Extraction of undisturbed soil columns)
- Destructive point sampling relating to available spatial information
- Destructive sampling following classical approaches
II. This enables measurement of emerging properties for all growth stages
III. This makes it possible to measure temporal evolution of spatial patterns for 6-year duration of the PP 2089, starting from completely homogeneous conditions (compare H2).Further information regarding the initial conditions of the soil plot experiments can be found in the publication by Vetterlein et al. “Experimental platforms for the investigation of spatiotemporal patterns in the rhizosphere – laboratory and field scale” published in the Journal of Plant Nutrition and Soil Science in 2020.
A list of all PP 2089 related publications can be found here:
Soil column experiments (SCE) with the two genotypes/textures will be conducted in climate chambers under well-defined and standardized conditions to study the pattern development during the first weeks of plant growth (compare H1).
For a detailed protocol how to set up a SCE please contact the SPP coordination. A Video how to fill a soil column can be seen here: Video filling soil columns
I. These will enable to combine different in situ measurements
II. These will enable to link in situ measurements to
• Destructive sampling maintaining spatial context1
• Minimum invasive point sampling relating to available spatial information
• Destructive sampling following classical approaches
III. These will enable measurement of emerging properties in the early stage