Table 1. Carbohydrate and amino acid concentrations in nectar, phloem sap and whole leaves from M. barclayana, L. erubescens and B. napus.
| Nectar [mM] | Phloem sap [mM] | Whole leaf1 [mM] | Whole leaf [µmol/g FW] | ||||
| a) M. barclayana | |||||||
| glucose | 233±71.3 | a | 0.2±0.4 | a | 14.3±3.3 | a | 11.1±2.5 |
| fructose | 179±47.6 | a | n.d. | 11.8±3.4 | a | 9.0±2.6 | |
| sucrose | 447±91.1 | a | 875±114 | a | 15.2±2.8 | a/b | 11.6±2.2 |
| raffinose | 0.8±0.7 | 26.9±3.9 | a | 1.2±0.2 | a | 0.9±0.2 | |
| stachyose | n.d. | 34.3±9.6 | a | 1.6±0.2 | a | 1.2±0.2 | |
| mannitol | 29.3±5.4 | a | 57.7±19.2 | a | 12.9±2.7 | a | 9.9±2.1 |
| antirrhinoside | 40.9±20.7 | a | 539±101 | a | 68.7±11.2 | a | 52.6±8.5 |
| sum of carbohydrates | 930±220 | a | 1533±107 | a | 126±17.8 | a | 96.2±13.6 |
| sum of amino acids | 0.8±0.2 | a | 106±12.9 | a | 14.3±0.7 | a | 10.9±0.5 |
| sum of glucose equivalents in glu, fru, suc | 1306 | a | 1750 | a | 56.5 | a | |
| b) L. erubescens | |||||||
| glucose | 85.9±32.4 | b | 0.5±0.3 | a | 5.7±1.1 | a | 4.8±1.0 |
| fructose | 118±43.3 | a | n.d. | 6.6±1.7 | a | 5.6±1.4 | |
| sucrose | 680±82.4 | b | 856±148 | a | 18.4±2.0 | a | 15.7±1.7 |
| raffinose | n.d. | 14.0±4.9 | b | 1.1±0.4 | a | 1.0±0.3 | |
| stachyose | n.d. | 18.9±5.8 | b | 1.1±0.1 | a | 1.0±0.1 | |
| mannitol | 6.0±1.3 | b | 43.5±19.0 | a | 14.8±3.9 | a | 12.6±3.3 |
| antirrhinoside | 4.3±1.4 | b | 32.5±13.5 | b | 16.2±2.1 | b | 13.8±1.8 |
| sum of carbohydrates | 894±154 | a | 965±145 | b | 64.0±9.5 | a | 54.6±8.1 |
| sum of amino acids | 0.2±0.1 | b | 81.1±23.4 | a | 7.9±0.2 | b | 6.8±0.2 |
| sum of glucose equivalents in glu, fru, suc | 1564 | a | 1712 | a | 49.1 | a | |
| c) B. napus | |||||||
| glucose | 858±311 | c | n.d. | 6.6±1.1 | a | 5.7±0.9 | |
| fructose | 782±323 | b | n.d. | 3.9±0.6 | a | 3.3±0.5 | |
| sucrose | 5.5±2.7 | c | 947±110 | a | 5.7±0.5 | b | 4.9±0.4 |
| raffinose | n.d. | n.d. | n.d. | n.d. | |||
| stachyose | n.d. | n.d. | n.d. | n.d. | |||
| mannitol | n.d. | n.d. | n.d. | n.d. | |||
| antirrhinoside | n.d. | n.d. | n.d. | n.d. | |||
| sum of carbohydrates | 1646±437 | b | 947±145 | b | 16.1±1.7 | b | 13.9±1.4 |
| sum of amino acids | 2.0±0.4 | c | 315±81.7 | b | 22.9±3.1 | a | 19.7±2.6 |
| sum of glucose equivalents in glu, fru, suc | 1651 | a | 1894 | a | 21.9 | a | |
| d) all species | p (nectar) | p (phloem) | p (whole leaf) | ||||
| glucose | 0.001 | 0.272 | 0.061 | ||||
| fructose | 0.003 | 0.039 | |||||
| sucrose | 0.001 | 0.603 | 0.027 | ||||
| raffinose | 0.003 | 0.060 | |||||
| stachyose | 0.003 | 0.039 | |||||
| mannitol | 0.001 | 0.006 | 0.046 | ||||
| antirrhinoside | 0.001 | 0.002 | 0.024 | ||||
| sum of carbohydrates | 0.022 | 0.011 | 0.027 | ||||
| sum of amino acids | 0.001 | 0.008 | 0.027 | ||||
| sum of glucose equivalents in glu, fru, suc | 0.321 | 0.603 | 0.061 |
1
Metabolite concentrations of whole leaves were estimated on the basis of leaf water contents and metabolite contents (µmol g−1 FW).
Abbreviations: FW = fresh weight; n.d. = not detectable (under detection limit of about 1 µM for each of the different carbohydrates and 0.1 µM for each of the different amino acids
Mean values from each five to six (nectar), four to five (phloem sap), and three biological (leaves) biological replications ± SD are shown.
Significant differences between plant species are indicated by different letters. The carbohydrate concentrations which were under the detection limit were not included in the post hoc test.