co2 concentration
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Daniel de A. Carreiro ◽  
Renata A. e Amariz ◽  
Luciana G. Sanches ◽  
Jackson T. Lobo ◽  
Vespasiano B. de Paiva Neto ◽  

ABSTRACT The objective of the present study was to evaluate the influence of the application of fenpropimorph and paclobutrazol on gas exchanges and photosynthetic pigments of ‘Tommy Atkins’ mango grown in the semi-arid region in different evaluation periods. Two experiments were carried out in ‘Tommy Atkins’ mango orchards in the first production cycle between September and December 2018 (first experiment) and between September and December 2019 (second experiment) in Petrolina, PE, Brazil. The experimental design adopted was randomized blocks in split plots in time, 4 × 4 + 1, with four replicates. The plots corresponded to the concentrations of fenpropimorph: 0, 0.7, 1.0, and 1.3 g per linear meter of plant canopy diameter plus the additional paclobutrazol treatment (1 g per linear meter of plant canopy diameter), and the subplots corresponded to the evaluation dates (0, 30, 60, and 90 days after the first application of treatments). The following traits were evaluated: CO2 assimilation rate, stomatal conductance, internal CO2 concentration, transpiration, water use efficiency, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids. The fenpropimorph dose of 1.3 g per linear meter of plant canopy promotes a higher rate of CO2 assimilation; however, paclobutrazol was more effective in the accumulation of chlorophyll a and total chlorophyll, and the use of fenpropimorph did not interfere in the concentration of photosynthetic pigments.

2022 ◽  
Vol 238 ◽  
pp. 111922
Lingfeng Dai ◽  
Lixin Lu ◽  
Chun Zou ◽  
Qianjin Lin ◽  
Wenxiang Xia ◽  

José A. C. Wanderley ◽  
Carlos A. V. de Azevedo ◽  
Marcos E. B. Brito ◽  
Fagner N. Ferreira ◽  
Mailson A. Cordão ◽  

ABSTRACT The objective of this study was to evaluate the gas exchange of ‘Redondo Amarelo’ passion fruit seedlings under the mitigating action of nitrogen fertilization on the salinity of irrigation water. The experiment was carried out in a greenhouse of the Universidade Federal de Campina Grande (CCTA-UFCG), Campus of Pombal, PB, Brazil, The experimental design was in randomized blocks, split plots, comprising five irrigation water electrical conductivities (plot) (ECw) (0.3; 1.0; 1.7; 2.4 and 3.1 dS m-1) and five doses of nitrogen (subplot) (60; 80; 100; 120 and 140% of 300 mg of N dm-3), in five blocks. Plants were grown in pots (Citropote JKS®) with volume of 3.780 mL, filled with soil, bovine manure, wood shavings in a proportion of 2:1:0.5 (mass basis), respectively. Water with salinity levels was applied in the period from 40 to 85 days after sowing. The internal CO2 concentration, transpiration, stomatal conductance and photosynthesis were measured at 55 and 70 days after sowing. There was an attenuating effect of nitrogen doses at irrigation water electrical conductivities of 1.7 and 2.4 dS m-1 on photosynthesis at 55 DAS. Irrigation water salinity reduces most of the variables evaluated, especially at the highest level studied (3.1 dS m-1).

2022 ◽  
Julia C. Tindall ◽  
Alan M. Haywood ◽  
Ulrich Salzmann ◽  
Aisling M. Dolan ◽  
Tamara Fletcher

Abstract. Reconciling palaeodata with model simulations of the Pliocene climate is essential for understanding a world with atmospheric CO2 concentration near 400 parts per million by volume. Both models and data indicate an amplified warming of the high latitudes during the Pliocene, however terrestrial data suggests Pliocene high latitude temperatures were much higher than can be simulated by models. Here we show that understanding the Pliocene high latitude terrestrial temperatures is particularly difficult for the coldest months, where the temperatures obtained from models and different proxies can vary by more than 20 °C. We refer to this mismatch as the ‘warm winter paradox’. Analysis suggests the warm winter paradox could be due to a number of factors including: model structural uncertainty, proxy data not being strongly constrained by winter temperatures, uncertainties on data reconstruction methods and also that the Pliocene high latitude climate does not have a modern analogue. Refinements to model boundary conditions or proxy dating are unlikely to contribute significantly to the resolution of the warm winter paradox. For the Pliocene, high latitude, terrestrial, summer temperatures, models and different proxies are in good agreement. Those factors which cause uncertainty on winter temperatures are shown to be much less important for the summer. Until some of the uncertainties on winter, high latitude, Pliocene temperatures can be reduced, we suggest a data-model comparison should focus on the summer. This is expected to give more meaningful and accurate results than a data-model comparison which focuses on the annual mean.

Rahul Banerjee ◽  
Pankaj Das ◽  
Bharti . ◽  
Tauqueer Ahmad ◽  
Manish Kumar

India is a country with an agrarian economy in which majority of its population rely on agriculture directly as their source of livelihoof. Climate has a very significant role in agricultural production. It predominantly influences growth of the crop, development of the crop and eventually crop yield. Climate also significantly influences the outbreak of disease and pest; it affects the requirement of water by the crop. Possible changes in weather factors, like precipitation, temperature and CO2 concentration are expected to have a significant impact on crop growth. If farmers are able to predict the weather activities and are aware of the effect of these activities on crop production, then it will be beneficial to them as a feasible plan can be devised synchronizing the crop production activities as per changes in the climatic conditions. In view of tackling the aforementioned problem, this article describes various statistical techniques that can play a crucial role in forecasting production of agricultural commodities changing climatic conditions.

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 92
Joanna M. Reinhold ◽  
Karthikeyan Chandrasegaran ◽  
Helen Oker ◽  
José E. Crespo ◽  
Clément Vinauger ◽  

Combining thermopreference (Tp) and CO2-gated heat-seeking assays, we studied the thermal preferendum and response to thermal cues in three Culex mosquito species exhibiting differences in native habitat and host preference (e.g., biting cold and/or warm-blooded animals). Results show that these species differ in both Tp and heat-seeking behavior. In particular, we found that Culex territans, which feed primarily on cold-blood hosts, did not respond to heat during heat-seeking assays, regardless of the CO2 concentration, but exhibited an intermediate Tp during resting. In contrast, Cx. quinquefasciatus, which feeds on warm blooded hosts, sought the coolest locations on a thermal gradient and responded only moderately to thermal stimuli when paired with CO2 at higher concentrations. The third species, Cx. tarsalis, which has been shown to feed on a wide range of hosts, responded to heat when paired with high CO2 levels and exhibited a high Tp. This study provides the first insights into the role of heat and CO2 in the host seeking behavior of three disease vectors in the Culex genus and highlights differences in preferred resting temperatures.

2022 ◽  
Tal Dahan-Meir ◽  
Thomas James Ellis ◽  
Fabrizio Mafessoni ◽  
Hanan Sela ◽  
Jacob Manisterski ◽  

Wild progenitors of major crops can help us understand domestication, and may also provide the genetic resources needed for ensuring food security in the face of climate change. We examined the genetic structure of a wild emmer wheat population, sampled over 36 years while both temperature and CO2 concentration increased significantly. The genotypes of 832 individuals revealed high genetic diversity over scales of tens of meters and were clustered spatially into ecological microhabitats. This pattern was remarkably stable over time. Simulations indicate that neutral processes alone are unlikely to fully explain the spatial and temporal stability of the population. These results are consistent with a role for local adaptation in shaping the fine-scale structure of plant populations, which is relevant for in-situ conservation strategies of biodiversity in nature.

2022 ◽  
Vol 14 (2) ◽  
pp. 268
Wenjing Yang ◽  
Yong Zhao ◽  
Qingming Wang ◽  
Buliao Guan

Vegetation regulates the exchange of terrestrial carbon and water fluxes and connects the biosphere, hydrosphere, and atmosphere. Over the last four decades, vegetation greening has been observed worldwide using satellite technology. China has also experienced a notably widespread greening trend. However, the responsiveness of vegetation dynamics to elevated CO2 concentration, climate change, and human activities remains unclear. In this study, we attempted to explore the impact of natural (precipitation, air temperature), biogeochemical (CO2), and anthropogenic drivers (nighttime light, afforestation area) on changes in vegetation greenness in the Haihe River Basin (HRB) during 2002–2018 at the county-level. We further determined the major factors affecting the variation in satellite-derived normalized difference vegetation index (NDVI) from moderate resolution imaging spectroradiometer (MODIS) for each county. The results indicated that over 85% of the counties had a significantly increased NDVI trend, and the average linear trend of annual NDVI across the study region was 0.0037 per year. The largest contributor to the NDVI trend was CO2 (mean contribution 45%), followed by human activities (mean contribution of 27%). Additionally, afforestation was a pronounced driving force for NDVI changes in mountainous areas, resulting from ecosystem restoration efforts. Our findings emphasize the crucial role of CO2 fertilization in vegetation cover change, while considering CO2 concentration, climate change, and human activities, and shed light on the significant influences of afforestation programs on water resources, especially in mountainous areas.

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