Table 1.
Trait | Abbreviation | Description | Unit1 | Range | Median | Mean ± SD2 |
---|---|---|---|---|---|---|
Average root diameter | ARD | Average individual root diameter | cm | 0.01–0.04 | 0.03 | 0.035 ± 0.0001** |
Maximum number of roots | MaxR | After sorting the number of roots crossing a horizontal line from smallest to largest, the maximum number is considered to be the 84th-percentile value (one standard deviation) | count | 2–19 | 8.33 | 8.94 ± 3.37** |
Median number of roots | MedR | The result of a vertical line sweep in which the number of roots that crossed a horizontal line was estimated, and then the median of all values for the extent of the network was calculated. | count | 1–10 | 3.67 | 3.99 ± 1.65** |
Network area | NWA | Total area covered by all roots | cm2 | 1.92–14.67 | 7.31 | 7.27 ± 2.15** |
Network depth | NWDep | The maximum depth reached by the root | cm | 10.95–24.91 | 20.29 | 20.04 ± 2.51 |
Network distribution | NWDist | The fraction of root network in the lower two third of the network (analogy of root depth density) | na | 0.26–1.98 | 0.79 | 0.865 ± 0.331 |
Network length | NWL | Total length of the entire network (∼half perimeter) | cm | 156.2–513.7 | 255.9 | 245.3 ± 77.5** |
Network perimeter | NWPer | Total length following all root surfaces | cm | 111.7–1061.7 | 539.1 | 510.2 ± 163.8** |
Network surface area | NWSA | The sum of surface area of all roots in the network | cm2 | 7.03–53.93 | 26.79 | 26.49 ± 7.94** |
Network volume | NWV | The total volume of all roots in the network | cm3 | 0.08–0.48 | 0.25 | 0.252 ± 0.074* |
Network width | NWW | The maximum linear width attained by the root | cm | 4.17–21.33 | 12.42 | 12.43 ± 3.12** |
Network width to depth | NWW_Dep | Ratio of NWW to NWDep (NWW/NWDep) | na | 0.203–1.316 | 0.64 | 0.632 ± 0.159* |
Root dry weight | RDWt | Oven dried root weight | g | 0.008–0.045 | 0.02 | 0.024 ± 0.006 |
Shoot dry weight | SDWt | Oven dried shoot weight | g | 0.015–0.064 | 0.03 | 0.028 ± 0.008* |
Shoot length | SL | Length of shoot from root collar to tip of the shoot | cm | 4.95–13.27 | 7.67 | 7.91 ± 1.30* |
Shoot : Root ratio | S_RDWt | Ratio of SDWt to RDWt (SDWt/RDWt) | na | 0.70–3.00 | 1.00 | 1.30 ± 0.44 |
Specific root length1 | SRL | Ratio of NWL to NWV(NWL/NWV) | cm-2 | 686.4–1249 | 990.4 | 976.6 ± 116.4** |
Specific root length2 | SRL2 | Ratio of NWL to RDWt (NWL/RDWt) | cm/g | 5,615–19,685.5 | 10877 | 10,765.99 ± 2,695.79 |
1cm = centimeter; g = gram; na = not applicable.
2SD = standard deviation; * and ** = significant at P < 0.05 and 0.001, respectively.