Effect of microclimate heterogeneity and ventilation system on entomopathogenic hyphomycete infection of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) in Mediterranean greenhouse tomato

Collaborative research was conducted in the south of France to assess constraints related to both climate heterogeneity and ventilation systems on the control potential of a Lecanicillium muscarium-based formulation against whiteflies in Mediterranean greenhouses. Four series of small-scale greenhouse trials were performed in 2001 and 2002. Two applications at 4–5 day intervals of Mycotal were conducted on young larvae of the greenhouse whitefly, Trialeurodes vaporariorum, at the rate recommended by the manufacturer (ca. 10¹⁰ viable spores per liter of water suspension). The climatic heterogeneity was taken into account by comparing the fungus-induced mortality of nymphs located on lateral row plants to that of nymphs on center row plants. In spite of significant differences in air flows (0.7–1.2 and 0.3 ms⁻¹, respectively) there was no effect on fungus efficacy (53–76% mortality). When comparing the influence of greenhouse equipment (sophisticated glasshouse vs. polyethylene-covered greenhouse), the fungus was not affected (89–96% mortality) in spite of significant differences in ventilation rates. The results confirmed that entomopathogenic Hyphomycetes have a strong potential for microbial control of whitefly larvae infesting tomato crops at moderate ambient humidity in Mediterranean greenhouses in spite of windy periods. These investigations confirmed that microclimatic conditions prevailing in the targeted insect habitat (under-leaf surface boundary layer) are greatly disconnected from that of both outside and inside the greenhouse. In northern Mediterranean greenhouses, non-stressed tomato crops provide unexpected favorable conditions for mycoinsecticide use against a phyllophagous insect.     

Estimating the aboveground biomass and carbon stocks of tall shrubs in a prerestoration degraded salt marsh

Wetlands play a vital role in Earth's carbon cycle and provide important ecosystem services. Their ability to perform their roles can be compromised by human activities that destroy or impair their functioning. The restoration of degraded wetlands may allow carbon cycle functioning, as well as other services, to be recovered. Predicting the potential outcomes from any restoration project requires upfront consideration, including via modeling possible changes in carbon stocks. In this study, we quantified the carbon stocks in tall shrub vegetation proliferating in a degraded salt marsh that is currently the subject of an extensive restoration project. We produced allometric models to estimate biomass and carbon stocks for three tall shrub species, which, along with other freshwater and upland species in the area, will die with continued restoration. Therefore, estimating the potential for carbon losses in biomass is important. We also developed a means of estimating carbon stocks in other nontree plants in the estuary area. Useful equations for estimating the biomass of tall shrubs are limited in general and lacking for degraded systems. Our study adds to the literature on carbon stocks in shrub species and fills a data gap for degraded ecosystems. It also contributes to the broader carbon feasibility study of the aforementioned restoration project that was designed to predict the overall net impact of the project on greenhouse gas emissions in the ecosystem.     

Seed-propagated Muscari comosum (L.) Mill.: Effects of sowing date and growing conditions

Muscari comosum is a widespread Mediterranean species with a long use as food. The edible part is the bitter bulb that has to be cooked. The increasing value of bulbs, also due to a renewed cultural interest toward traditional foods and their benefits for health, claims to enhance the agricultural production. Surprisingly, no agronomic studies about the best practice of propagation exist. We tested whether and how germination rate and weight and size of bulbs, after one growing season, were affected by sowing date (autumn–spring), growing condition (greenhouse, shaded greenhouse and open field), and container’s volume. Results showed that the best-sowing period ranges between September and January; following this period there is a huge decrease in germination rate. The time of seedling emergence was higher in open field than in protected environment. The longer interval of growing was observed with the sowing of October that produced heavier and larger bulbs. The best combination to obtain larger bulbs is sowing in October under greenhouse. However, under shaded conditions it was possible to obtain satisfactory results even with medium-late sowing (December and January). Containers with higher volume generally performed better. We conclude that mass propagation of M. comosum could be efficiently performed for agronomic purposes using nurseries. In fact, due to the high rate of germination and to the ease of obtaining the seeds from wild populations or from cultivations, there is the possibility to produce large quantities of bulbs to develop new crops of this traditional food.     

International Regulation on Low-Carbon Shipping for Climate Change Mitigation: Development,Challenges, and Prospects

This article outlines the contribution of international shipping to climate change and examines different approaches to regulate international shipping activities to reduce greenhouse gas (GHG) emissions. It considers challenges such as the allocation of GHG emissions to individual states, the selection of the most effective mitigation and regulatory measures, the potential for a disproportionate burden to fall upon developing states, and the debate about whether the United Nations (UN) or the International Maritime Organization (IMO) is the appropriate international authority to regulate emissions from international shipping.     

A proposal concerning the origin of life on the planet earth

Summary The widely accepted Oparin thesis for the origin and early evolution of life seems sufficiently far from the true state of affairs as to be considered incorrect. It is proposed that life on earth actually arose in the planet's atmosphere, however an atmosphere very different from the present one. Because of an extremely warm surface, the early earth may have possessed no liquid surface water, its water being partitioned between a molten crust and a fairly dense atmosphere. Early preliving systems are taken to arise in the droplet phase in such an atmosphere. The early earth, which resembled Venus then and to some extent now, underwent a transition to its present condition largely as a result of the evolution of methanogenic metabolism.     

Gas composition and respiration of water oak (Quercus nigra L.) and green ash (Fraxinus pennsylvanica Marsh.) roots after prolonged flooding

Summary We compared the effects of 9.5 months of a continuous flooding treatment with a drained control treatment on one year-old seedlings of green ash (Fraxinus pennsylvanica Marsh.) and water oak (Quercus nigra L.), two tree species common to the bottomland-hardwood forests of eastern North America. The internal root gas composition of the more flood tolerant species, green ash, maintained higher oxygen and lower carbon dioxide concentrations under the flooding treatment than water oak. This apparently resulted in differences in rhizosphere oxidation. The amounts of Fe and Mn and the Fe/Mn ratio of the root coating extracted from trees in reduced soil conditions were much higher for the green ash than the water oak. It is argued that this reflects differences in the ability of these two species to maintain rhizosphere oxidation under prolonged periods of flooding and to prevent the accumulation of reduced potentially phytotoxic compounds. Alcohol dehydrogenase activity increased in the green ash and decreased in the water oak in the flooded treatment. This indicated that the better adapted species was able to rely upon increased anaerobic respiration in order to compensate for the decreased root oxygen supply, but the water oak was unable to maintain previous levels of respiration, probably as the result of sulfide toxicity.     

Does it pay to be science-based green? The impact of science-based emission-reduction targets on corporate financial performance

The number of companies with highly ambitious carbon emission targets is increasing rapidly. So-called science-based emission-reduction targets (SBTs) are aligned with the aim of the Paris Climate Agreement to limit global warming to below 2°C and preferably to 1.5°C. These voluntary corporate emission targets are substantially more challenging than companies’ prevailing reduction objectives, because climate science guides the target setting. By 2021, more than 2200 companies had publicly engaged in SBTs, covering more than a third of the global market capitalization. The number of participating firms has essentially doubled every year since the first SBTs in 2015. Despite this increased empirical relevance, the impact of SBTs on firm outcomes remains unclear. Notably, their effect on corporate financial performance (CFP) is unknown. The present study addresses this research gap by empirically examining the relationship between corporate carbon emission performance (CCP) and CFP of firms with SBTs from 2015 to 2020. The cross-country panel comprises 2014 observations of 465 firms. Our findings indicate a positive association between CCP and CFP for firms engaging in SBTs, implying a positive relation between decarbonization efforts and financial results. We thereby advance research on the important question of when it pays to be green. On a practical level, we provide transparency on the effects of SBTs for managers and climate-change advocates.     

Embryo-rescue culture of the ‘Galia’ muskmelon (Cucumis melo L. var. reticulatus Ser.) male parental line

In order to obtain a reliable embryo-rescue technique for wild type (WT) and transgenic ‘Galia’ muskmelon male parental line we evaluated three distinct parameters: nutrient media (E20A basic medium and E21, with six new supplements), two culture systems (removing the embryo from the seed or intact seed), and the use of embryos from fruit at increasing days post pollination (DPP). Transgenic muskmelon plants with the ACO gene in antisense orientation were obtained using a protocol previously described. Fruits were harvested at 4, 10, 17, 24 and 30 DPP. The embryos were either removed from the seeds or left in the seeds and placed in E-20A or E-21 medium for 30–35 days. Seedlings (well developed cotyledon) from all treatments were transferred to E-21 elongation medium, incubated 5 weeks, and transferred to soil to evaluate growth. The efficiency of this technique was greater as embryo age (DPP to rescue the embryo) was increased. Embryos 17–30 DPP had the greatest efficiency for embryo rescue, although embryos could be rescued as early as 4 DPP. The number of rescued embryos using an improved medium (E-21) was greater than E-20A basic medium. Survival efficiency rate was the same for WT and transgenic embryos. We have obtained a competent embryo-rescue technique for WT and transgenic ‘Galia’ male parental line with better efficiency rates than others previously reported.