Summary1. Most plant species rely upon multiple lines of defence that develop or change functions with leaf age. To date, the effects of leaf age on multiple defence traits have been insufficiently elucidated. For Mallotus japonicus (Euphorbiaceae), we report a shift from direct to indirect defence against herbivory. That shift occurs gradually during leaf ageing. 2. First, the densities of trichomes and pellucid dots, the numbers of extrafloral nectaries (EFNs) and pearl bodies, and the number of ants on leaves of M. japonicus were examined in the field at weekly intervals. Secondly, herbivore species and the degree of herbivory were examined. Thirdly, the effects of ants on herbivore exclusion were investigated experimentally in the field. Finally, to confirm the effectiveness of trichomes and pellucid dots for defence against two herbivore species [the adult flea beetle, Aphthona strigosa (Coleoptera: Chrysomelidae), and the inchworm, Ascotis selenaria (Lepidoptera: Geometridae)], both young and middle-aged leaves were tested using laboratory bioassay. 3. On newly emerged leaves, densities of trichomes and pellucid dots were extremely high, but they decreased rapidly with leaf age. The respective quantities of EFNs that were actually secreting nectar, the pearl bodies, and the ants on middle-aged leaves were greater than those on leaves of other ages. On M. japonicus, we found 11 herbivorous insects, among which Ap. strigosa and As. selenaria were the principal herbivores. 4. The damaged leaf areas of ant-excluded plants were much larger than those of control plants. Most herbivory was attributable to As. selenaria. Laboratory bioassay revealed that against Ap. strigosa and small As. selenaria larvae, trichomes and pellucid dots in young leaves functioned well, although those in middle-aged leaves did not. 5. Synthesis. Young M. japonicus leaves are defended against herbivores through the use of direct defence traits such as trichomes and pellucid dots. However, the plant uses indirect defence traits for middle-aged leaves. This shift from direct defence to indirect defence with leaf ageing supports the 'optimal defence theory': plants have evolved multiple defence traits to maximize their fitness.

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These results suggest that direct defence traits function regardless of light conditions, but light conditions affected the development of indirect defence traits.

Although soil nutrients can influence the defence strategy of plants that have multiple defence traits, to date, there have been few studies to examine this. To evaluate the effect of soil nutrients on multiple plant defences, we cultivated Mallotus japonicus under three soil nutritional conditions in the field, and experimentally examined the expression of a physical defence trait (trichomes), chemical traits (pellucid dots), and biotic traits (extrafloral nectaries (EFNs) and pearl bodies) of the plants, and the number of ants visiting them. Under the low soil nutritional condition, plants strongly expressed the physical defence by trichomes and chemical defence by pellucid dots, meaning that the young plants adopted direct defences under the poor soil nutritional condition. Under the high soil nutritional condition, in contrast, the plants strongly expressed the indirect defence traits. They produced abundant EFNs and pearl bodies, and attracted many ants. These results suggest that young plants of M. japonicus use different defence modes in response to different soil nutritional conditions.

The Yb(III) and Lu(III) sandwich complexes of 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine (H2obPc) were prepared and characterized. Those electrochemical properties in CH2Cl2 were studied by means of cyclic voltammetry and absorption spectra in 320–1600 nm region monitored during controlled-potential electrolysis.