while jacozine N-oxide concentrations did not show a correlation between leaf
surface and leaf tissue. Furthermore, of the senecionine-like PAs, only one minor
compound (eruciflorine N-oxide) correlated, and of the erucifoline-like PAs, only
Table 2 Correlations between concentration of leaf-tissue and leaf-surface pyrrolizidine alkaloids
(PAs) of 37 F 2 hybrid plants of a cross between Jacobaea aquatica and Jacobaea vulgaris
Group
Pyrrolizidine alkaloid
r/rs
Adjusted P
b
Senecionine-like PAs
Senecionine
a
0.11
ns
Senecionine N-oxide
0.16
ns
Intergerrimine
a
0.01
ns
Intergerrimine N-oxide
0.19
ns
Retrorsine
a
0.19
ns
Retrorsine N-oxide
a
0.17
ns
Eruciflorine N-oxide
a
0.62
**
Riddelliine
a
0.39
ns
Riddelliine N-oxide
a
0.03
ns
Seneciphylline
0.37
ns
Seneciphylline N-oxide
0.11
ns
Acetylseneciphylline
0.47
ns
Acetylseneciphylline N-oxide
0.22
ns
Spartiodine N-oxide
0.38
ns
Jacobine-like PAs
Jacobine
0.74
***
Jacobine N-oxide
0.69
***
Jacoline
0.60
**
Jacoline N-oxide
0.61
**
Jacozine
0.78
***
Jacozine N-oxide
0.47
ns
Erucifoline-like PAs
Erucifoline
0.44
ns
Erucifoline N-oxide
0.52
*
Acetylerucifoline N-oxide
0.20
ns
Otosenine-like PAs
Otosenine
0.69
***
Onetine
a
0.54
**
Florosenine
a
0.93
***
Floridanine
a
0.68
***
PA free bases
0.75
***
PA N-oxides
0.41
ns
Sum concentration of senecionine-like PAs
0.19
ns
Sum concentration of jacobine-like PAs
0.80
***
Sum concentration of erucifoline-like PAs
0.51
*
Sum concentration of otosenine-like PAs
0.72
***
Sum concentration of all PA
0.50
*
Adapted from Cheng et al. [44]
a PAs with concentrations that were not normally distributed, for which Spearman correlation tests
were carried out, while Pearson correlation tests were carried out for all other PAs
b
P-values of the correlation testes were adjusted by Sequential Bonferroni method Significance
codes: ns not significant
* P < 0.05, ** P < 0.01, *** P < 0.001
258
D. Cheng