Clodionafop, an acetyl-coenzyme A carboxylase (ACCase) inhibitor, changed the shape of the chlorophyll fluorescence induction curve (Kautsky curve) in barley and oat in greenhouse experiments. Biomass ED50, based on log-logistic dose–response curves, for barley was considerably higher than that for oat in all experiments. Biomass ED50 and relative potency (ED50 [barley]/ED50 [oat]) were consistent among experiments when sprayed at the same phenological stage of plant development. Especially at high doses, clodinafop changed the shape of the Kautsky curve more for oat than for barley. From the numerous parameters that can be derived from the OJIP steps of the Kautsky curve, we found that (1) F vj, the relative changes at the J step [F vj = (F m − F j)/F m], (2) area between Kautsky curve and maximum fluorescence (F m), and (3) F v/F m, maximum quantum efficiency of Photosystem II [F v/F m = (F m − F 0)/F m], were closely linked to the biomass dose–response relationships for both species. The linkage between biomass and the fluorescence parameters may be used to shorten the screening period for ACCase inhibitors.

Two recent meta-analyses on second-generation antidepressants versus placebo in mild to moderate forms of major depression, based on data on all randomized clinical trials using the Hamilton Depression Scale (HAMD) submitted to FDA, have shown an effect size of ∼0.30 in favour of antidepressants in the acute therapy of major depression. The clinical significance of an effect size at this level was found to be so poor that these meta-analyses have subscribed to the myth of an exclusively placebo-like effect of second-generation antidepressants. A re-allocation of HAMD items focusing on those items measuring severity of clinical depression, the HAMD6, has identified effect sizes of ⩾0.40 for second-generation antidepressants in placebo-controlled trials for which even a dose–response relationship can be demonstrated. In the relapse-prevention phase during continuation therapy of patients with major depression, the advantage of second-generation antidepressants over placebo was as significant as in the acute therapy phase. To explore a myth is not to deny the facts but rather to re-allocate them.

Spring wheat (Triticum aestivum cv. Nandu) cultivated under glasshouse conditions was exposed to ozone in large fumigation chambers for 2 wk. Different exposure regimes were applied as constant concentrations as well as with ozone peaks, partly under equal dose-conditions, in times of high solar radiation during different stages of development (seedling, late tillering, anthesis). Chlorophyll fluorescence was monitored and amounts of carbohydrates (hexoses, sucrose, starch) and chlorophyll were measured in young leaves (seedling) and flag leaves (late tillering, anthesis) during and after ozone exposure. Although seedlings showed no significant response in photosynthesis, strong effects on photosynthesis and carbohydrate accumulation were measured when plants were fumigated during anthesis, especially after a heat stress period preceding ozone treatments. Under equal dose conditions chlorophyll fluorescence parameters (Fv[ratio ]Fm) and electron transport rate decreased and sucrose content of flag leaves increased significantly if ozone at a concentration of 220 μg m−3 was supplied for 4 h, indicating that peak concentrations show stronger effects than constant concentrations. The reaction of wheat plants is dependent on environmental conditions such as preceding heat stress and on the developmental stage during exposure. The results favour the hypothesis that photoinhibition and disturbance of photosynthesis are only secondary effects as a consequence of retarded sucrose export from the leaf, because of damage at the plasma membrane.