The theory of plant-insect coevolution provides for diffuse coevolution and the expectation that plants evolve broad-spectrum chemical defenses with which some insects coevolve by detoxifying and using the compounds as host-location cues. Specific biochemical modes of action have been assigned to relatively few such defense chemicals and one major class, the terpenoids, is investigated here. Six terpenoids inhibited the enzyme acetylcholinesterase (derived from electric eel) and elicited the appropriate in vivo effects of insect paralysis and mortality. The diterpene gossypol was a reversible uncompetitive inhibitor. Five monoterpenes, representing a range of functional groups, were reversible competitive inhibitors apparently occupying at least the hydrophobic site of the enzyme's active center. Such data suggest the involvement of acetylcholinesterase in the coevolved insect response to terpenoids.

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Interspecific populations derived from crossing cultivated field pea, Pisum sativum, with the wild pea relative, Pisum fulvum, were scored for pod and seed injury caused by the pea weevil, Bruchus pisorum. Pod resistance was quantitatively inherited in the F2 population, with evidence of transgressive segregation. Heritability of pod resistance between F2 and F3 generations was very low, suggesting that this trait would be difficult to transfer in a breeding program. Seed resistance was determined for the F2 population by testing F3 seed tissues of individual F2 plants and pooling data from seed reaction for each F2 plant (inferred F2 genotype). Segregation for seed resistance in the F2 population of the cross Pennant/ATC113 showed a trigenic mode of inheritance, with additive effects and dominant epistasis towards susceptibility. Seed resistance was conserved over consecutive generations (F2 to F5) and successfully transferred to a new population by backcross introgression. Seed resistance in the backcross introgressed population segregated in a 63 : 1 ratio, supporting the three-gene inheritance model. It is proposed that complete resistance to pea weevil is controlled by three major recessive alleles assigned pwr1, pwr2, and pwr3, and complete susceptibility by three major dominant alleles assigned PWR1, PWR2, and PWR3. It is recommended that large populations (>300 F2 plants) would be required to effectively transfer these recessive alleles to current field pea cultivars through hybridisation and repeated backcrossing.

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Tandem evaluation of ionic liquids and imidazolium salts toxicity and performance in dye sensitised solar cells is presented.