TABLE 1.
List of 59 traits and physiological variables identified, their descriptions from the original papers, and the corresponding number of studies and species. A study is defined as an experiment carried out on a given species in a paper (i.e., a paper may present multiple studies if it covers multiple species). Units are not reported as they differ widely across studies
| Group | Trait and physiological variable name/abbreviation | Short description | No. of studies | No. of species |
|---|---|---|---|---|
| Leaf gas exchange, development, and anatomy | 01. Whole‐plant transpiration rate | Whole‐plant water loss measured gravimetrically | 38 | 21 |
| 02. Leaf transpiration rate | Single‐leaf gas exchange measured via IRGA system | 31 | 25 | |
| 03. Stomata conductance | Leaf conductance to H2O using IRGA/porometer | 62 | 35 | |
| 04. Photosynthetic rate | Single‐leaf gas exchange measured via IRGA system | 36 | 25 | |
| 05. Leaf area | Measured on one or more representative leaves | 62 | 36 | |
| 06. Leaf expansion rate | Rate of leaf expansion per unit of time | 4 | 2 | |
| 07. Leaf dry mass | Mass of oven‐dried leaves | 21 | 11 | |
| 08. Specific leaf area | Ratio of leaf area to its mass | 37 | 26 | |
| 09. Stomatal size | Stomatal dimensions | 27 | 10 | |
| 10. Stomatal density | Stomata number per unit area | 37 | 22 | |
| 11. Stomatal index | Number of stomata relative to epidermal cells | 15 | 7 | |
| 12. Trichome density | Number of trichomes per unit area | 1 | 1 | |
| 13. Epicuticular wax | Amount of leaf epicuticular wax | 2 | 2 | |
| 14. Epidermal cell size | Epidermal cell dimensions | 9 | 9 | |
| 15. Vein density | Number of veins per unit area | 2 | 2 | |
| 16. Leaf thickness | Leaf thickness measured directly by microscope | 10 | 10 | |
| 17. Air space fraction in leaf | Area of intercellular air space in the spongy mesophyll | 5 | 5 | |
| 18. Spongy mesophyll cell number | Number of spongy mesophyll cells per unit area | 2 | 2 | |
| 19. Length of mesophyll cell | Length of the palisade mesophyll cells | 4 | 4 | |
| Leaf hormonal, carbohydrate, and mineral status | 20. Leaf ABA | Abscisic acid concentration in the leaf | 13 | 6 |
| 21. Leaf starch | Starch content in the leaf | 4 | 3 | |
| 22. Leaf soluble carbohydrates | Soluble carbohydrates content in the leaf | 4 | 3 | |
| 23. Leaf N | Nitrogen content in the leaf | 24 | 17 | |
| 24. Leaf P | Phosphorus content in the leaf | 14 | 6 | |
| 25. Leaf K | Potassium content in the leaf | 14 | 7 | |
| 26. Leaf Ca | Calcium content in the leaf | 20 | 14 | |
| 27. Leaf Mg | Magnesium content in the leaf | 7 | 6 | |
| 28. Leaf Fe | Iron content in the leaf | 3 | 2 | |
| 29. Leaf Na | Sodium content in the leaf | 6 | 4 | |
| 30. Leaf S | Sulfur content in the leaf | 3 | 3 | |
| 31. Leaf Zn | Zinc content in the leaf | 2 | 2 | |
| 32. Leaf Mo | Molybdenum content in the leaf | 1 | 1 | |
| 33. Leaf B | Boron content in the leaf | 2 | 2 | |
| 34. Leaf V | Vanadium content in the leaf | 2 | 2 | |
| 35. Leaf methionine | Methionine content in the leaf | 1 | 1 | |
| 36. Leaf alpha‐aminobutyric acid | Alpha‐aminobutyric acid content in the leaf | 1 | 1 | |
| 37. Leaf glutamine | Glutamine content in the leaf | 1 | 1 | |
| 38. Leaf threonine | Threonine content in the leaf | 1 | 1 | |
| 39. Leaf allothreonine | Allothreonine content in the leaf | 1 | 1 | |
| Whole‐plant mass, development, and architecture | 40. Whole‐plant dry mass | Total mass of oven dried stems, leaves and roots | 36 | 25 |
| 41. Shoot dry mass | Mass of oven dried stems and leaves | 80 | 62 | |
| 42. Root dry mass | Mass of oven dried whole‐roots systems or fine roots | 30 | 15 | |
| 43. Plant height | Plant height measured from the collar | 61 | 47 | |
| 44. Leaf number | Total number of leaves per plant | 32 | 22 | |
| 45. Number of branches and tillers | Total number of branches and tillers per plant | 3 | 3 | |
| 46. Diameter of stem base | Measured near the soil | 2 | 2 | |
| 47. % Leaves with wide insertion angle | Percentage of leaves with an angle higher than 67° | 1 | 1 | |
| 48. % Leaves with narrow insertion angle | Percentage of leaves with an angle lower than 22° | 1 | 1 | |
| 49. Fractional radiation interception | Ratio of transmitted to incident short wave radiation | 1 | 1 | |
| Yield and reproductive development | 50. Yield | Fruit, grain, leaf, root yields of crop plants | 25 | 12 |
| 51. Number of flowers | Number of flowers or flowering buds per plant | 12 | 8 | |
| 52. Number of bracts | Number of bracts per plant | 1 | 1 | |
| 53. Flower size | Dimensions of flowers | 1 | 1 | |
| 54. Time to flowering | Time from the experiment initiation to flowering | 8 | 8 | |
| 55. Time to anther opening | Number of hours until most or all anthers are open | 9 | 4 | |
| 56. Sugar in fruit | Total sugar content in fruit | 2 | 1 | |
| 57. K in fruit or flower | Potassium content in the fruit or flower | 3 | 2 | |
| 58. Ca in fruit or flower | Calcium content in the fruit or flower | 3 | 2 | |
| 59. Methionine in fruit | Methionine content in the fruit or flower | 1 | 1 |
Abbreviations: ABA, abscisic acid; B, boron; Ca, calcium; Fe, iron; IRGA, infrared gas analyzer; K, potassium; Mg, magnesium; Mo, molybdenum; N, nitrogen; P, phosphorus; S, sulfur; V, vanadium; Zn, zinc.