Flowering rush (Butomus umbellatus L.) is an emergent perennial monocot that has invaded aquatic systems along the U.S. - Canadian border. Currently, there are two known cytotypes of flowering rush, diploid and triploid, within the invaded range. Although most studies have focused on the triploid cytotype, little information is known about diploid plants. Therefore, phenology and resource allocation were studied on the diploid cytotype of flowering rush in three study sites (Mentor Marsh, Ohio; Tonawanda Wildlife Management Area, New York; and Unity Island, New York) to understand seasonal resource allocation, environmental influences on growth, and to optimize management strategies. Samples were harvested once a month from May to November at each site from 2021 to 2023. Plant metrics were regressed to air temperature, water temperature, and water depth. Aboveground biomass peaked from July-September and comprised 50 to 70% of total biomass. Rhizome biomass peaked from September to November and comprised 40 to 50% of total biomass. Rhizome bulbil densities peaked from September to November at 3,000 to 16,000 rhizome bulbils m-2. Regression analysis resulted in strong negative relationships between rhizome starch content and air temperature (r2=0.52) and water temperature (r2=46). Other significant, though weak, relationships were found including a positive relationship between aboveground biomass and air temperature (r2=0.17), a negative relationship between rhizome bulbil biomass and air temperature (r2=0.18) and a positive relationship between leaf density and air temperature (r2=0.17). Rhizomes and rhizome bulbils combined stored up to 60% of total starch and present a unique challenge to management as these structures cannot be reached directly with herbicides. Therefore, management should target the aboveground tissue before peak production (July) to reduce internal starch storage and aim to limit regrowth over several years.

Studies on the effect of nanofertilizers (NF) in physiological performance of plants is scarce, especially that related to substances encapsulated into silicon dioxide (SiO2) nanoparticles in cocoa plants. The effect of foliar application of SiO2-NF on nutrient contents, gas exchange, photochemical activity, photosynthetic pigments, total soluble protein (TSP), photosynthetic nitrogen use efficiency (PNUE), and growth in seedlings of two cocoa clones (OC-61 and BR-05) in a greenhouse was assessed. Spraying with SiO2-NF increased net photosynthetic rate (A) by 16 and 60% and electron transport rate (J) by 52 and 162% in clones OC-61 and BR-05, respectively, without changes in photosynthetic pigment concentration in either clone. The SiO2-NF caused a decrease of 37 and 22% in stomatal conductance in OC-61 and BR-05, respectively; a similar trend was observed in transpiration rate, causing an increase of 42 and 100% in water use efficiency in OC-61 and BR-05, respectively. In both clones, diameter of graft increased on average 28% with SiO2-NF. Higher photosynthetic capacity was related to an increase in leaf N, P, and TSP. A significant reduction in PNUE (A/N ratio) was found in OC-61, whereas in BR-05 PNUE increased after spraying with SiO2-NF. Overall, spraying with SiO2-NF had a positive effect on photosynthetic processes in both cocoa clones, associated with an increase in nutrients content, which translated into improved growth. A differential physiological response to spraying with SiO2-NF between clones was also found, with BR-05 being the clone with a better physiological response during the establishment and development stages.

The evolution of melt ponds on Arctic sea ice in summer is one of the main factors that affect sea-ice albedo and hence the polar climate system. Due to the different spectral properties of open water, melt pond and sea ice, the melt pond fraction (MPF) can be retrieved using a fully constrained least-squares algorithm, which shows a high accuracy with root mean square error ~0.06 based on the validation experiment using WorldView-2 image. In this study, the evolution of ponds on first-year and multiyear ice in the Canadian Arctic Archipelago was compared based on Sentinel-2 and Landsat 8 images. The relationships of pond coverage with air temperature and albedo were analysed. The results show that the pond coverage on first-year ice changed dramatically with seasonal maximum of 54%, whereas that on multiyear ice changed relatively flat with only 30% during the entire melting period. During the stage of pond formation, the ponds expanded rapidly when the temperature increased to over 0°C for three consecutive days. Sea-ice albedo shows a significantly negative correlation (R = −1) with the MPF in melt season and increases gradually with the refreezing of ponds and sea ice.

Increasing the air temperature from 20 to 32 C, the water temperature from 21 to 30 C, and the wind velocity from 0 to 8 km/h increased the loss of EPTC (S-ethyl dipropyl carbamothioate) from water applied through a sprinkler by 24 to 138%. Decreasing the water temperature from 21 to 10 C decreased the loss of EPTC by 35 to 50%. Decreasing the water pressure or nozzle size by 33% or doubling the herbicide concentration did not affect the percentage of EPTC lost.

The effects of 1.24 kg ha−1 ammonium sulfate, 5 g ae ha−1 of the isopropylamine salt of imazapyr, and air temperatures of 18, 27, or 35 C at 40 or 100% relative humidity (RH) on the absorption and translocation of the ammonium salt of 14C-imazethapyr applied postemergence to pitted morningglory were evaluated. Absorption of 14C-imazethapyr was greater at 100 than at 40% RH (88 vs. 47%). At 40% RH, absorption was increased to 79% by the addition of ammonium sulfate. At 100% RH absorption was similar with all treatments. Translocation of 14C-imazethapyr applied alone was greater at 100 than at 40% RH (34 vs. 17%). Addition of ammonium sulfate increased translocation at 40% RH but not at 100%. Addition of imazapyr did not affect 14C translocation. Distribution of 14C throughout the plant was more acropetal than basipetal with the greatest distribution at 35 C.

Toxicity and translocation of nonradiolabeled and translocation of 14C-labeled sethoxydim {2-[1-(ethoxyimino)-butyl]-5-[2-(ethylthio)-propyl]-3-hydroxy-2-cyclohexen-1-one} in common bermudagrass [Cynodon dactylon (L.) Pers. ♯3 CYNDA] were evaluated for foliar treated plants grown 2 or 4 days under controlled environmental conditions. Nonradiolabel treated plants were further grown in the greenhouse for the remainder of 3 weeks. Shoot injury of intact plants was greatest (90%) and regrowth of plants clipped after 2 days treatment each was least (< 5%) at 35 C and 100% RH. At 35 C and 40% RH and at 18 C (40 and 100% RH), shoot injuries were 60 to 68%, regrowth in lengths were 82 to 87%, and in fresh weights were 55 to 74%, respectively. After 2 days treatment, absorption of 14C-activity was greatest (70%) at 35 C and 100% RH, moderate (56%) at 35 C and 40% RH, and least (33 to 43%) at 18 C and 40 and 100% RH, respectively. At 35 C, translocation was approximately 4 fold greater at 100% and 2 fold greater at 40% RH than at 18 C at either RH. Autoradiography indicated the greatest distribution of the radiolabel at 35 C.

Experiments were conducted on uptake and translocation of butyl ester of 14C-fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} in green foxtail [Setaria viridis (L.) Beauv. # SETVI]. Absorption of 14C-fluazifop reached 67.6% 12 h after treatment with the petroleum oil additive compared to 44.0% when applied alone. Maximum 14C-fluazifop absorption detected was 74.2% after 48 h with the oil additive compared to 58.6% after 72 h when applied alone. Translocation of 14C-fluazifop was greater when applied with the oil additive than alone, but translocation did not increase after 12 h. Absorption and translocation of 14C-fluazifop by green foxtail was greater when applied with the oil additive than alone in all environments. The oil additive overcame the reduced absorption of 14C-fluazifop applied alone with low temperature (20 C), relative humidity (40%), and soil fertility (0.25× strength Hoagland's solution), but not the reduced absorption and translocation with an increase in stress to −10 bars. 14C-fluazifop lost as vapors from the treated green foxtail leaf was 4.1% when applied alone compared to 0.6% when applied with an oil additive.

Corn (Zea mays L. ‘Pioneer 3732′) showed little to no injury following the postemergence-directed application of sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexen-1-one} plus crop oil concentrate (COC) at 56 g/ha plus 1.25% (v/v) at nine locations across Midwestern U.S. in 1984 and 1985. Little corn injury also occurred for the postemergence-directed application of sethoxydim plus COC at 110 g/ha plus 1.25% (v/v) at most locations in both years. Considerable variation in tolerance was seen across locations for over-the-top applications of sethoxydim at all rates tested and for the directed application at 220 g/ha. Although corn at most locations showed no yield reduction with the over-the-top application of sethoxydim plus COC at 56 g/ha plus 1.25% (v/v), a 70% yield reduction occurred in one location in one year. For an over-the-top application of sethoxydim plus COC at 110 g/ha plus 1.25% (v/v), yields ranged from 3 to 95% of the untreated check in 1984, and from 3 to 88% in 1985. Stand reductions from an over-the-top application of sethoxydim plus COC at 220 g/ha plus 1.25% (v/v) ranged from 0 to 99%. A significant negative correlation was found between yield of corn treated over the top with sethoxydim and precipitation on the day of application and in the week following application. Air temperature on the day of application was positively correlated with corn injury from over-the-top and directed sethoxydim applications, but no correlation existed between percent relative humidity and corn injury. Open pan evaporation and solar radiation before and after application were not correlated with corn injury from sethoxydim.

Toxicity of non-radiolabeled and absorption and translocation of 14C-activity of applied 14C-acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} in showy crotalaria (Crotalaria spectabilis Roth) were evaluated in the growth chamber at air temperatures of 18, 27, or 35 C and 40 or 100% relative humidity (RH). Four days after treatment, acifluorfen applied over-the-top at 0.1 kg/ha resulted in 64 to 95% injury, but did not kill showy crotalaria. Acifluorfen was more toxic at 100% than at 40% RH. At either 40 or 100% RH, acifluorfen was more toxic at 27 and 35 C than at 18 C. Plants were placed in the greenhouse 4 days after treatment. At 6 weeks after treatment, there was extensive regrowth, and injury to all plants was less than 32%, except for those plants initially treated at 18 C and 40% RH for 4 days. These plants showed 76% injury. Acifluorfen applied to a single leaf midway up the stem caused 80 to 100% injury to the immature leaves near the apex, but less than 30% injury to lower leaves. Absorption of 14C-activity from 14C-acifluorfen applied to a single leaf midway up the shoot varied from 8 to 76% after 2 days. At either 40 or 100% RH, absorption was approximately four-fold greater at 27 and 35 C than at 18 C. At all temperatures tested, absorption was three- to four-fold greater at 100% than at 40% RH.

Toxicity of nonradiolabeled and translocation of 14C-labeled metriflufen3 {2-[4-(4-trifluoromethylphenoxy)phenoxy] propanoic acid} in cotton (Gossypium hirsutum L. ‘Stoneville 213’) were evaluated under different environmental conditions as affected by surfactant and by the maturity of stem or leaf tissue at the place of herbicide application. Cotton was very tolerant to metriflufen, with the greatest tolerance at high temperatures. The herbicide entered the plant quite rapidly and autoradiographs indicated that radioactivity from the herbicide moved freely throughout the plant. Relative humidity (RH) between 40 and 100% had little effect on metriflufen toxicity. Two weeks after treatment with metriflufen at 0.5 kg/ha, cotton was essentially free of injury symptoms at 35 C, but injury was as great as 41 and 13% at 18 and 25 C, respectively. All plants recovered fully after 6 additional weeks in the greenhouse. When surfactant was added to the spray solutions, cotton injury was frequently increased during the first 2 weeks but not after 8 weeks. Accumulation of 14C at the site of 14C-metriflufen application was 31 to 65% after 48 h. Between 16 and 51% of the applied 14C moved from the treated area by translocation into other parts of the plant, or by volatilization into the atmosphere. Movement was greatest from stem tissue at 35 C and 100% RH. There was no correlation between 14C movement and herbicide toxicity within the plant. The selectivity of metriflufen to cotton probably results from deactivation by, or tolerance within, the plant rather than from differential absorption and translocation of the herbicide.

Metriflufen {2-[4-(4-trifluoromethylphenoxy)phenoxy] propanoic acid} was applied as the methyl ester at 0.28 and 0.56 kg/ha over-the-top to johnsongrass [Sorghum halepense (L.) Pers.] growing from rhizomes and to soybeans [Glycine max (L.) Merr. ‘Lee 68′]. After herbicide treatment, plants were grown in the growth chamber for 14 days at 16, 24, or 32 C with relative humidity (RH) at 40 or 100% at each air temperature. Johnsongrass was not controlled at 16 C regardless of metriflufen rate, RH, or the addition of nonoxynol [α-(p-nonylphenyl)-ω-hydroxypoly (oxyethylene)] (with 9.5 moles of polyoxyethylene) surfactant at 0.25 (g/100 ml) to spray solutions. Johnsongrass control at 24 C varied from 5 to 98%, with significantly better control at 100% than at 40% RH. The presence of surfactant increased johnsongrass control at 24 C and 40% RH but not at 24 C and 100% RH. Johnsongrass control at 32 C varied from 48 to 98%, and it was not increased by the presence of the surfactant, regardless of metriflufen rate or RH level. At 16 C metriflufen was more injurious to soybeans than to johnsongrass, but at 24 and 32 C johnsongrass control was significantly greater than soybean injury. The presence of surfactant in spray solutions generally did not increase soybean injury, regardless of temperature or RH level. These results suggest that metriflufen is most selective in controlling johnsongrass in soybeans at 24 C, especially under high RH.

Postemergence applications of flufenprop-methyl [methyl-N-benzoyl-N (3-chloro-4-fluorophenyl)-2-amino-propionate] for wild oat (Avena fatua L.) control in spring wheat (Triticum aestivum L.), durum wheat (Triticum durum L.), and barley (Hordeum vulgare L.) were evaluated in the field, greenhouse, and controlled environmental chambers. Wild oat control with flufenprop-methyl was greater at the five-leaf stage than three and one-half or two-leaf stage of growth. Wild oat control was not reduced when flufenprop-methyl was tank-mixed with bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one, 2,2-dioxide]. Tolerance of spring and durum wheat cultivars to flufenprop-methyl was acceptable; however, tolerance of barley cultivars was considerably more variable. Air temperature after treatment, soil fertility, and moisture did not influence wild oat control with flufenprop-methyl; however, a simulated rainfall of 1 mm within 1/2 h or 4 mm within 4 h after application reduced wild oat control.

The ground temperature down to 60 cm depth in western Dronning Maud Land (WDML), has been recorded since 2009. The study area is situated in a blockfield that comprises a shallow active layer above permafrost. Using ground thermal regimes and regional climate data, the temporal (seasonal and annual) variability of the active layer was characterized. Active layer depth was calculated for each site for five consecutive summers from 2009/10–2013/14, showing interannual variability with no overall trends of decreasing or increasing active layer depth. Particular attention was paid to 2010 as it matched the average for the ground thermal regimes over the six year study period, as well as the interpolation period used by Meteonorm®. Analysis showed significant synchronous relationships of ground thermal regimes with air temperature and incoming radiation. Moreover, a correlation between pressure and measured ground temperature during the transitional season of the Southern Annual Oscillation in May and September was identified.

Near-surface air temperature is an important determinant of the surface energy balance of glaciers and is often represented by a constant linear temperature gradients (TGs) in models. Spatio-temporal variability in 2 m air temperature was measured across the debris-covered Miage Glacier, Italy, over an 89 d period during the 2014 ablation season using a network of 19 stations. Air temperature was found to be strongly dependent upon elevation for most stations, even under varying meteorological conditions and at different times of day, and its spatial variability was well explained by a locally derived mean linear TG (MG–TG) of −0.0088°C m−1. However, local temperature depressions occurred over areas of very thin or patchy debris cover. The MG–TG, together with other air TGs, extrapolated from both on- and off-glacier sites, were applied in a distributed energy-balance model. Compared with piecewise air temperature extrapolation from all on-glacier stations, modelled ablation, using the MG–TG, increased by <1%, increasing to >4% using the environmental ‘lapse rate’. Ice melt under thick debris was relatively insensitive to air temperature, while the effects of different temperature extrapolation methods were strongest at high elevation sites of thin and patchy debris cover.

This study investigated the mass balance, melting, near-surface ice thermal structure and meteorological conditions of the Ecology and Sphinx glacier system (ESGS), located on King George Island, Antarctic Peninsula. The study also analysed the role of climate change in glacial retreat of the ESGS in the long (1979–2012) and short term, with a particular focus on the impact on the 2012–13 mass balance of the ESGS. In 2012–13, the glaciers had a mean annual net mass balance of +17.8 cm w.e., but over the long term the glaciers have been receding in this region. The area loss of the ESGS between 1979 and 2012 amounted to 41%. This investigation of mass balance is especially important as it offers one of only a few records available on King George Island. The mean near-surface ice temperature (February to June 2012) for the Ecology and Sphinx glaciers was -0.3°C and -1.0°C at 10 m depth, respectively. From 1948–2012, the air temperature on King George Island increased by 1.2°C (0.19°C per decade).

Ongoing climate variations in the Arctic and Antarctic pose an apparent paradox. In contrast to the large warming and loss of sea ice in the Arctic in recent decades, Antarctic temperatures and sea ice show little change except for the Antarctic Peninsula. However, model simulations indicate that the Arctic changes have been shaped largely by low-frequency variations of the atmospheric circulation, superimposed on a greenhouse warming that is apparent in model simulations when ensemble averages smooth out the circulation-driven variability of the late 20th century. By contrast, the Antarctic changes of recent decades appear to be shaped by ozone depletion and an associated strengthening of the southern annular mode of the atmospheric circulation. While the signature of greenhouse-driven change is projected to emerge from the natural variability during the present century, the emergence of a statistically significant greenhouse signal may be slower than in other regions. Models suggest that feedbacks from retreating sea ice will make autumn and winter the seasons of the earliest emergence of the greenhouse signal in both Polar Regions. Priorities for enhanced robustness of the Antarctic climate simulations are the inclusion of ozone chemistry and the realistic simulation of water vapour over the Antarctic Ice Sheet.

Research was performed in Poggio Casciano Estate (Chianti area, central Italy) with the aim of defining a general approach to analyse the spatial variability of temperature at the microscale. Hourly data were collected from a network of 27 temperature stations covering an area of about 120 ha and determination coefficients r between station pairs on the basis of different geo-topographical factors were calculated. The data were analysed in order to investigate trends describing the spatial distribution of temperature inside the study area. The results pointed out a strong effect of some topographical condition on the distribution of thermal patterns, in particular altitude and the distance from valley bottoms. The results are discussed in order to formulate a general approach for the characterisation of climatic conditions at small scale.