Article Figures & Data
Figures
- Figure 1.
Spatial variability in Glc exudation from maize primary roots. A, Primary roots of 2-d-old maize seedlings grown in well-watered vermiculite were imaged 26 min after being placed on gel containing Ampliflu Red reagent with GO and HRP (complete medium, denoted by C) or C medium without HRP (C-HRP) or GO (C-GO). The blue arrow indicates filter paper strips containing air-dried 120 mm d-Glc that were placed on the gel containing the C, C-HRP, or C-GO assay constituents as positive and negative controls. The development of magenta color indicates the production of resorufin from Ampliflu Red in a Glc-dependent manner. The experiment was repeated at least four times with similar results. B, Epifluorescence imaging of the differential Glc exudation from the maize primary root. Intact seedlings were placed on gel containing Glc assay constituents (GO, HRP, and Ampliflu Red reagent), and the time course of Glc exudation from the primary root tip and root base was monitored by epifluorescence microscopy. The fluorescence per image was calculated using ImageJ software, and the pixels per unit of area are shown. A detailed analysis of the quantification is shown in Supplemental Figure S3. Data are means ± se; n = 3 to 4 roots. The relative fluorescence scale is shown at the bottom of B. The experiment was performed twice with similar results, and representative images are shown.
- Figure 2.
Quantification of Glc exudation from the tip and base of maize primary roots. A, Two-day-old maize seedlings were placed on filter paper strips for 30 min to collect Glc exuded from the root tip and base. Glc from triplicate samples (with exudates pooled from nine seedlings each) was extracted and quantified by HPAE chromatography. The efficiency of Glc extraction was assessed by including filter paper strips with 450 ng of d-Glc (FP+G). Filter paper (FP) strips without added Glc or exudates were used as controls. Data are means ± se; n = 3 (from triplicate samples). Letters denote significant differences between samples as determined by one-way ANOVA and the Student-Newman-Keuls test (P ≤ 0.05). B, Average Glc exudation rate (ng min−1 during the first 30 min of incubation on the gel) from the tip and base of the well-watered maize primary root. Data are means ± se; n = 3 (from triplicate samples). The asterisk denotes a significant difference at P < 0.01 using Student’s t test. The experiment was performed twice with similar results.
- Figure 3.
Glc exudation from water-stressed maize primary roots. A, Primary roots of 2-d-old water-stressed maize seedlings grown in vermiculite at a water potential of −1.4 MPa were imaged 26 min after being placed on complete (C) or control (C-HRP or C-GO) gels. The experiment was performed three times with similar results. B, Average Glc exuded from the root tip and base of the water-stressed maize primary root per min (Glc exuded from the roots was collected, extracted, and quantified as described in “Materials and Methods”). Data are means ± se; n = 3 (from triplicate samples). The experiment was performed twice with similar results. No statistical differences were observed.
- Figure 4.
Glc exudation from the primary root of soybean (A), common bean (B), cotton (C), sorghum (D), wheat (E), and rice (F) seedlings. Roots of 2-d-old seedlings grown in well-watered vermiculite were imaged at various times after being placed on complete (C) or control (C-HRP or C-GO) gels. The blue arrow indicates filter paper strips containing air-dried 120 mm d-Glc that were placed on the gel containing the C, C-HRP, or C-GO assay constituents as positive and negative controls. The experiments were repeated two or more times with similar results.
Additional Files
Supplemental Data
Supplemental Figures and Tables
- Supplemental Data -
Supplemental Figures 1-9 and Supplemental Tables 1 and 2
- Supplemental Data -
