Article Figures & Data
Figures
- Figure 1.
The distribution of root length of H. lanatus tillers originating from seed collected at the uncontaminated and the As-contaminated site after 7 d of growth in a nutrient solution supplemented with 133 μm As(V). The root length classes correspond to 0 to 1 cm (class 1), 1.1 to 2 cm (class 2), etc. Seed-grown plants (46 from uncontaminated and 35 from contaminated site) were used to produce tillers (five from each plant).
- Figure 2.
The root length of H. lanatus tillers after 7 d in a nutrient solution supplemented with 133 μm As(V) plotted against the ratio of the root length in the high-As (133 μm Na2HAsO4) and zero-As solutions after 7 d. Each observation is the average of five tillers isolated from individual plants originating from seed collected at an uncontaminated or an As-contaminated site.
- Figure 3.
Concentrations of total As in roots and shoots of H. lanatus clones tolerant and non-tolerant to As. Plants were exposed to a range of As(V) concentrations in the low-P (10 μm = LP) and the high-P (100 μm = HP) nutrient solutions for 30 d. The fraction (in %) of total shoot As in relation to the total plant As is presented above or next to the bar (se in parentheses). Data represent the means + se. * indicates that dead plant material was included.
- Figure 4.
Concentrations of As(V) in roots and shoots of H. lanatus clones tolerant or non-tolerant to As. Plants were exposed to a range of As(V) concentrations in the low-P (10 μm = LP) and the high-P (100 μm = HP) nutrient solutions for 30 d. Data represent the mean + se. * indicates that dead plant material was included.
- Figure 5.
Concentrations of As(III) in roots and shoots of H. lanatus clones tolerant or non-tolerant to As. Plants were exposed to a range of As(V) concentrations in the low-P (10 μm = LP) and the high-P (100 μm = HP) nutrient solutions for 30 d. Data represent the mean + se. * indicates that dead plant material was included.
- Figure 6.
The proportion of As(III) in H. lanatus roots or shoots plotted against the concentration of total As in roots or shoots. Tolerant (T) and non-tolerant (NT) clones were grown in nutrient solutions with different levels of As(V) (1.33, 8, or 107 mm) and phosphate (10 μm = LP or 100 μm = HP). Only the data for plant material that was alive at the time of harvest were included.
- Figure 7.
Concentrations of As(III) and As(V) in H. lanatus roots and shoots plotted against the concentration of total As in the roots or shoots. Tolerant (T) and non-tolerant (NT) clones were grown in nutrient solutions with different levels of As(V) (1.33, 8, or 107 μm) and phosphate (10 μm or 100 μm). Only the data for plant material that was alive at the time of harvest were included.
- Figure 8.
Dry weight of H. lanatus roots and shoots plotted against the proportion of As(III) present in roots or shoots. Tolerant (T) and non-tolerant (NT) clones were grown in nutrient solutions with different levels of As(V) (1.33, 8, or 107 μm) and phosphate (10 μm = LP or 100 μm = HP). Only the data for plant material that was alive at the time of harvest were included.
Tables
- Table I.
Phosphorus concentration and dry weight of roots and shoots of Holcus lanatus plants of As-tolerant (T) and non-tolerant (NT) clones exposed to different concentrations of As(V) (1.33, 8 or 107 μm) and phosphate (10 or 100 μm)
Data represent the means (se in parentheses). *, includes dead plant material.
As(V) Concentration Phosphorus Concentration H. Ianatus Clone Dry Wt Phosphorus Concentration Roots Shoots Roots Shoots μM mg plant-1 mg g-1 dry wt 1.33 10 T 129 (20) 213 (4) 1.8 (0.03) 1.5 (0.07) NT 104 (20) 171 (2) 2.2 (0.2) 1.5 (0.2) 100 T 423 (80) 234 (20) 3.1 (0.1) 5.4 (0.1) NT 415 (30) 173 (8) 3.8 (0.2) 6.1 (0.5) 8 10 T 379 (50) 162 (8) 2.0 (0.06) 1.4 (0.1) NT 123 (50) 85 (8) 3.1 (0.6) 2.4 (0.6) 100 T 430 (80) 238 (4) 3.1 (0.08) 4.9 (0.5) NT 380 (80) 172 (6) 3.5 (0.2) 6.3 (0.2) 107 10 T 76 (1) 114 (20) 3.0 (0.004) 2.4 (0.04) NT 5 (0.1)* 28 (7)* 10.1 (0.5)* 4.1 (0.2)* 100 T 414 (30) 198 (3) 2.8 (0.1) 4.0 (0.04) NT 227 (20) 142 (3) 3.5 (0.4) 4.5 (0.1) - Table II.
Analysis of variance for dry weight and phosphorus concentrations of shoots and roots of H. lanatus
Significance was defined as P ≤ 0.05. d.f., degrees of freedom.
Source d.f. P Values Dry Wt Phosphorus Concentration Roots Shoots Roots Shoots As 2 0.009 <0.001 0.147 0.451 clone 1 0.009 <0.001 0.002 0.001 P 1 <0.001 <0.001 <0.001 <0.001 As.clone 2 0.217 0.036 0.742 0.138 As.P 2 0.168 <0.001 0.008 <0.001 clone.P 1 0.59 0.096 0.826 0.491 As.clone.P 2 0.159 0.093 0.13 0.3 Error 12 - Table III.
Analysis of variance of total As, As(III), and As(V) concentrations in shoots and roots of H. lanatus
Data were log(10) transformed. Significance was defined as P ≤ 0.05. d.f., degrees of freedom.
Source d.f. P Values Total As Concentration Total As(III) Concentration Total As(V) Concentration Roots Shoots Roots Shoots Roots Shoots As 2 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Clone 1 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 P 1 <0.001 <0.001 <0.001 <0.001 <0.001 0.031 As.clone 2 0.151 <0.001 0.141 0.176 <0.001 <0.001 As.P 2 0.252 0.002 <0.001 <0.001 0.149 0.019 clone.P 1 0.79 <0.001 0.338 0.019 0.011 <0.001 As.clone.P 2 0.383 <0.001 0.002 0.092 0.002 <0.001 Error 12 - Table IV.
The fraction (in %) of As(III) in relation to the total As concentration in roots and shoots of H. lanatus clones tolerant (T) or non-tolerant (NT) to As
Plants were exposed to a range of As(V) concentrations in the low P (10 μm) and the high P (100 μm) nutrient solutions for 30 d. Data represent the mean (se in parentheses). *, includes dead plant material.
As(V) Concentration Phosphorus Concentration Clone Proportion of As(III) In Roots In Shoots μM % of total plant As 1.33 10 T 75 (4) 88 (2) NT 89 (0.2) 93 (1) 100 T 38 (5) 54 (2) NT 53 (8) 71 (2) 8 10 T 84 (1) 74 (4) NT 87 (4) 67 (0.5) 100 T 50 (8) 47 (1) NT 75 (5) 70 (7) 107 10 T 92 (3) 45 (1) NT 9 (0.7)* 7 (0.3)* 100 T 77 (5) 32 (1) NT 85 (1) 28 (1) - Table V.
Analysis of variance of fraction of As(III) as % of total As concentrations in shoots and roots of H. lanatus
Results from dead plant material were omitted. Main and interaction effects were considered significant when P ≤ 0.05. Significance was defined as P ≤ 0.05. d.f., degrees of freedom.
P Values Source d.f. Proportion of As(III) In Roots In Shoots As 2 <0.001 <0.001 Clone 1 0.019 0.001 P 1 <0.001 <0.001 As.clone 2 0.036 0.022 As.P 2 0.001 0.003 Clone.P 1 0.007 0.002 As.clone.P 1 (1) 0.054 <0.001 Error 11 (1)
