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The general objective is the study of the photosynthesis process in corn plants, the necessary basis for the great adaptation capacity of plants to climate changes. These studies are important because they participate in the identification of solutions involved in increasing corn production and its quality. The experience was organized at the farm "Vasile Adamachi" within the USV Iasi, in the spring of 2021 and the analyzes on the collected physiological material were carried out in the plant physiology laboratory of the USV Iasi. The research material was represented by the hybrid DKC 4598 produced by the Bayer Group with the FAO 350-390 group. The analysis of the photosynthesis process in maize in the context of the climatic conditions specific to the growing season of 2021 was carried out by quantitatively determining of the content of photosynthetic pigments and chlorophyll fluorescence. The results obtained by the analyse of the photosynthesis process were correlated with the production obtained. The results obtained from the fluorescence analysis show us that the corn plants studied had the highest light quantification capacity in the 6 and 8 node phenophases. The recorded differences do not show an effort in the ability of the plants to adapt to the weather conditions of 2021 in North-Eastern Moldova. [ABSTRACT FROM AUTHOR]

We investigate the impacts of climate changes in corn crop profitability and productivity in Parana (Brazil), using SISDRENA model, considering different spacings between drains. SISDRENA model is used as input, daily precipitation, and potential evapotranspiration, properties of the drainage system, data of crop requirement, and physical and hydrological soil parameters. We use climate data from the Eta model. The baseline period of the simulation is from 1981 to 2005. For the future projections, we use the greenhouse gas emission scenarios RCP4.5 and RCP8.5, from 2046 to 2070. We concluded that there are variations in evapotranspiration over the years in the historical simulation, but in the future, this variability tends to be higher. There is a tendency for increased evapotranspiration in both scenarios in the future. We found a large variability of precipitation in both historical simulation and future projections. Changes in precipitation depend on location. In terms of both profitability and productivity, the 10-m spacing between drains is the most recommended. In historical simulation and future projections, it is found large variability in corn productivity over the years. We found that there is no agreement between RCP4.5 and RCP8.5, which shows uncertainty in the results. In general, in RCP4.5 the tendency is to increase 3% of productivity (not significant), while in RCP8.5 the tendency is to decrease 1% (significant), compared to the baseline period. This research contributes to better farmer management and decision making, providing recommendations for the best layout for current and future climate, and indicates trends in corn productivity in future scenarios. [ABSTRACT FROM AUTHOR]

Under climate change, alterations to precipitation and temperature regimes are expected to impact ecosystem structure and function. These impacts may in part be determined by feedbacks between plants and associated microbes, including both endophytic fungal symbionts and viral pathogens., To test potential key components of these feedbacks in a grassland system, we conducted a field experiment that factorially manipulated temperature regime, precipitation regime and endophyte infection of a dominant species, Schedonorus arundinaceus. After one growing season, we evaluated the four most frequently occurring grass species for infection by three species of barley and cereal yellow dwarf viruses (B/ CYDVs). For S. arundinaceus, we also tracked changes in viral prevalence over an additional two growing seasons, for a total of three growing seasons., Plant species identity played a strong role in determining virus prevalence; Poa pratensis and Paspalum dilatatum were more frequently infected than either S. arundinaceus (endophyte infected or endophyte free) or Eleusine indica. Both elevated temperature and elevated precipitation impacted virus prevalence, but effects varied among years and interacted with fungal endophyte symbiosis for S. arundinaceus., In the final year of data collection, elevated precipitation increased virus prevalence in endophyte-infected, but not endophyte-free, S. arundinaceus. In the same year, but regardless of endophyte infection, elevated temperature by itself increased virus prevalence for S. arundinaceus. This effect of temperature on virus prevalence may have been driven by vector abundance because the viruses are obligately aphid-transmitted, and aphids were found more frequently in heated plots., Synthesis. Overall, our investigation experimentally demonstrates strong combined impacts of biotic and abiotic factors on disease dynamics in a grassland system. Impacts of climate change on virus prevalence in grasslands may depend on the responses of aphid vectors and the presence of endophytic fungal symbionts. [ABSTRACT FROM AUTHOR]