The effects of elevated CO2 (E-CO2) on maize and Asian corn borer (ACB), Ostrinia furnacalis, in open-top chambers were studied. The plants were infested with ACB and exposed to ambient and elevated (550 and 750 μl/l) CO2. E-CO2 increased the plant height and kernel number per ear. The plants had lower nitrogen contents and higher TNC: N ratios under E-CO2 than at ambient CO2. The response of plant height to E-CO2 was significantly dampened in plants with ACB infestation. However, the weight gain of the survivors declined in plants grown under E-CO2. Moreover, the plant damage caused by ACB was not different among the treatments. Overwintering larvae developed under E-CO2 had a lower supercooling point than those developed under ambient CO2. The results indicated that there was a positive effect of E-CO2 on the accumulation of maize biomass, i.e., the "air-fertilizer" effect, which led to a nutritional deficiency in the plants. The fitness-related parameters of ACB were adversely affected by the CO2-mediated decreased in plant nutritional quality, and ACB might alter its food consumption to compensate for these changes. Larval damage to maize under E-CO2 appears to be offset by this "air-fertilizer" effect, with reductions in larval fitness.
High-capacity Li-rich layered oxides (LLOs) hold giant promise as cathodes for Li-ion batteries but still suffer from cycling instability and voltage decay. The oxygen redox reaction and phase transformation to spinel are major incentives for performance deterioration. Hence, we propose a La-doping strategy to stabilize surface oxygen and reduce spinel phase components. The special La–O bond could exhibit not only an electrovalent characteristic bond but also a relative covalent property, which enhances the stability of lattice oxygen and the reversibility of oxygen redox. The spinel phase composition of surface area could be reduced through La doping, which suppresses capacity fade and voltage decay. Accordingly, the La-doping LLOs with Li and O vacancy defects forming at the surface area exhibit excellent reversible capacity (225 mA h/g at 1 C and 145 mA h/g at 5 C) and rate performance (80.68 and 81.76% capacity retention over 300 cycles at 1 and 5 C). This study could be extended to synthesize other advanced cathode materials for next-generation Li-ion batteries and even be helpful to the R&D of rare-earth utilization.
Abstract Polyphenism, a common phenomenon in nature, is an important form of adaptation in a diverse environment. Corn leaf aphid (CLA), Rhopalosiphum maidis , (Hemiptera: Aphididae), exhibit wing polyphenism in response to poor habitat quality. In this study, we focused on the effects of crowding and thermal cues on morph determination of CLA. Five developmental stages of aphids (1 st to 4 th nymphs and maternal adults) with increased population densities, were tested under two kinds of temperature patterns, i.e., A) a constant temperature of 22 °C with 2 h exposure to high temperature in the range of 35 to 39 °C during mid-photophase and B) different constant temperatures in the range of 22–30 °C with 2 h exposure to high temperature of 39 °C during mid-photophase. Crowding was found to directly impact winged induction. The 1 st and 2 nd nymphs were more sensitive for alate morphs induction under high density. In addition, temperature played a significant role in wing production, with the temperature setting of 26/39 °C in pattern B inducing higher alate morphs and survival than other temperature settings. Therefore, we hypothesize that warmer climate with brief high temperature is more favourable for survival and alate morphs production, but cool weather and transient extreme high temperature (>39 °C) is detrimental for CLA. Our results provide a new perspective on understanding the interactions between changes in extreme high temperatures and insect densities that differentially affect wing polymorphism for further demographic and distribution rates of species across temporal and spatial scales.
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