Supplementary materials
Manuscript title: Dynamic root responses to drought and rewatering in two wheat
(Triticum aestivum) genotypes (submitted to Plant Soil)
Sebastian Steinemann1;2, Zhanghui Zeng1,3 Alan McKay4, Sigrid Heuer1, Peter Langridge1, Chun
Y Huang1*
1
Australian Centre for Plant Functional Genomics, School of Agriculture, Food and Wine,
University of Adelaide, PMB1 Glen Osmond, SA 5064, Australia
2
Plant Breeding, Department of Plant Sciences, Technische Universität München, Liesel-
Beckmann-Str.2, 85354 Freising, Germany
3
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang
University, Hangzhou, Zhejiang, 310058, China
4
Plant and Soil Health, South Australian Research and Development Institute, GPO Box 397,
Adelaide, SA 5001, Australia
*Corresponding author:
Chun Y. Huang
Email: [email protected]
1
Fig. S1 Soil sampling for analyses of root length density and root DNA concentration.
The photo shows a pot after two soil cores were taken using a soil corer of 2.5 cm in diameter
(A). Soil samples were bagged and put on ice for the analysis of root DNA concentration in soil
(B).
2
Fig. S2 Root morphology of nodal roots from two contrasting genotypes under moderate
drought or well-watered treatments.
Plants were grown in pots and treated either with moderate drought (Drought) or with a wellwatered (WW) regime, and harvested at day 50. Roots were washed free of soil, and nodal roots
were cut from the root-shoot junction, separated and scanned in a root positioning tray. The three
positions of nodal roots used for determination of root morphological parameters in cross
sections are indicated in drought-treated RAC875.
3
Fig. S3 Root morphology of primary roots from two contrasting genotypes under moderate
drought or well-watered treatments.
Plants were grown in pots and treated either with moderate drought (Drought) or with a wellwatered (WW) regime, and harvested at day 50. Roots were washed free of soil, and primary
roots were cut from the root-shoot junction, separated and scanned in a root positioning tray. The
two positions of primary roots used for determination of root morphological parameters in cross
sections are indicated in WW-treated RAC875. The proximal position was 2 cm from the rootshoot junction, whereas the distal position was 4 cm from the root apex.
4
Fig. S4 Cross sections of nodal roots of RAC875 and Kukri from well-watered and droughttreated plants.
Cross sections of nodal roots 3 cm from the root-shoot junction of well-watered Kukri (A) and
RAC875 (B) at day 50. Cross sections of nodal roots for moderate drought-treated Kukri (C) and
RAC875 (D) at day 50. Plants were grown in pots and treated either with moderate drought or
with a well-watered regime, and harvested at day 50. Roots were washed free of soil. Nodal roots
were hand-cut at 3 cm from the root-shoot junction, stained with phloroglucinol and viewed
under a microscope with bright light. Bars indicate 50 µm. Different root tissues are denoted as
cortex (CO), endodermis (EN), stele (ST), protoxylem (PX) and metaxylem (MX).
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Fig. S5 Cross sections of primary roots (2 cm from the root-shoot junction) in two contrasting
genotypes.
Cross sections of primary roots from well-watered Kukri (A) and RAC875 (B) at day 50. Cross
sections of primary roots from moderate drought-treated Kukri (C) and RAC875 (D) at day 50.
Plants were grown in pots and treated either with moderate drought or with a well-watered
regime, and harvested at day 50. Roots were washed free of soil. Primary roots at 2 cm from
the root-shoot junction were sectioned, stained with 0.05% toluidine blue and viewed under a
microscope with bright light. Bars indicate 50 µm. Different root tissues are denoted as cortex
(CO), endodermis (EN), stele (ST), protoxylem (PX) and metaxylem (MX)
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Fig. S6 Cross sections of primary roots (4 cm from the root tip) in two contrasting genotypes.
Cross sections of primary roots from well-watered Kukri (A) and RAC875 (B) at day 50. Cross
sections of primary roots from moderate drought-treated Kukri (C) and RAC875 (D) at day 50.
Plants were grown in pots and treated either with moderate drought or with a well-watered
regime, and harvested at day 50. Roots were washed free of soil. Primary roots at 4 cm from
the root tip were sectioned, stained with 0.05% toluidine blue and viewed under a microscope
with bright light. Bars indicate 50 µm.
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Fig. S7 Anatomical features of cross sections of nodal roots at 8 cm and 13 cm from the rootshoot junction in two contrasting genotypes.
(A-D) Cross sections of nodal roots at 8 cm from the root-shoot junction. (E-H) Cross sections
of nodal roots at 13 cm from the root-shoot junction. (A, E) Number of metaxylem per root.
(B, F) Metaxylem diameter. (C, G) Metaxylem area per root. (D, H) Protoxylem area per root.
Plants were grown in pots and treated either with moderate drought or with a well-watered
regime, and harvested at day 50. Cross sections were hand-cut at 8 and 13 cm from the rootshoot junction. Each box represents eight sections. Boxes show the median, the 25th and 75th
percentiles. Whiskers denote the largest and smallest values. P values were calculated with
student’s t-test, and ns is not significant.
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