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Murdannia nudiflora (L.) Brenan is a day flower that is dependent on entomophilous pollination. Despite the lack of pollinator attractants and its short flower longevity, M. nudiflora shows high rates of fecundity, which lead to their rapid dispersal. In addition to monitoring the vegetative reproductive methods and the effect of select environmental parameters (atmospheric temperature, relative humidity, and precipitation rates) in M. nudiflora, we evaluated mating systems in this species via artificial crosses. This species has evolved to undergo autogamy to ensure reproductive success when pollinators are insufficient; cleistogamous flowers are produced for optimal pollinator activity when environmental conditions are unfavorable. The number of cleistogamous flowers produced was found to be positively correlated with humidity and precipitation rates, and negatively correlated with temperature. In addition, it was found that high humidity and precipitation always hinder insect pollinators. Therefore, the combination of vegetative reproduction, entomophily, and cleistogamous self-pollination helps this weedy species to propagate with maximum efficiency. Murdannia nudiflora employs pre-anthesis cleistogamy as a mating strategy for reproductive assurance while retaining mechanisms that promote out-crossing. Key words: anthesis, breeding systems, chasmogamous, entomophilous, pollen viability, spontaneous autogamy. Murdannia nudiflora (L.) Brenan est une espece dont les fleurs fletrissent rapidement qui depend de la pollinisation entomophile. Malgre l'absence de substances attractives pour les pollinisateurs et la faible longevite de ses fleurs, M. nudiflora presente de hauts taux de fecondite qui donnent lieu a sa dispersion rapide. En plus de suivre les methodes de reproduction vegetative et l'effet de parametres environnementaux selectionnes (temperature atmospherique, humidite relative et taux de precipitation), les auteurs ont evalue les systemes de reproduction chez cette espece au moyen de croisements artificiels. Cette espece a evolue vers l'autogamie afin d'assurer son succes reproducteur lorsque les pollinisateurs sont en nombre insuffisant; les fleurs cleistogames sont produites pour optimiser l'activite des pollinisateurs lorsque les conditions environnementales sont defavorables. Le nombre de fleurs cleistogames produites s'avere correle positivement avec les taux d'humidite et de precipitations, et correle negativement avec la temperature. Par ailleurs, il appert qu'une humidite et des precipitations elevees genent toujours les insectes pollinisateurs. Ainsi, la combinaison de la reproduction vegetative, de l'entomophilie et de l'autofecondation cleistogame aide cette espece de mauvaise herbe a se propager avec une efficacite maximale. Murdannia nudiflora utilise la cleistogamie preanthese comme strategie pour assurer sa reproduction tout en conservant des mecanismes qui favorisent le croisement eloigne. [Traduit par la Redaction] Mots-cles : anthese, systeme de reproduction, chasmogame, entomophile, viabilite du pollen, autogamie spontanee., Introduction Murdannia Royle is a genus within the dayflower family Commelinaceae, which includes 61 species worldwide. The genus is primarily Asiatic, with species inhabiting diverse habitats. Murdannia nudiflora (L.) Brenan, [...]

The ocean-atmosphere interface (OAI) is a dynamic boundary of complex energy and chemical exchange and is important to understand mechanisms that influence it. Research is on-going to improve how the OAI is represented within tropical cyclone (TC) prediction models and ensembles. Motivation for improvement stems from a rapidly changing thermodynamic environment caused by climate change. Such changes are not widely understood, as no scientist has observed or measured these changes on long time scales. We assert the possibility of climate change, its underlying uncertainties and modified atmospheric variability can potentially lead to rapid intensification. We argue simplification of OAI to capture model ensemble data uncertainty through probabilistic modeling via Bayesian Neural Network (BNN). We retrieved area--averaged satellite data from NOAA and NASA, created a data set of several parameters--atmospheric air temperature (AirTemp), atmospheric temperature anomaly (ATA), atmospheric carbon dioxide (C[O.sub.2]), sea surface temperature (SST), tropical cyclone heat potential (TCHP), mid- layer wind shear (WindShear), convective available heat potential (CAPE), vertical motions (VerticalMotion), precipitable water content (PWC) and our derived OAI parameter as inputs into a BNN via R programming language. We used the BNN to model the OAI and inferenced potential favorability of an OAI given conditional probabilities. The BNN network rejected ATA and WindShear. Results showed probabilities acceptable within expert interpretations of parameter interactions to predict favorable OAI conditions. Keywords: Tropical Storm, Bayesian Neural Network, Ocean-Atmosphere Interface, INTRODUCTION Uncertainties in tropical cyclone (TC) intensification forecasting continue in modern-day forecasting modelsl. Recent storms such as TC Matthew (2016) and TC Irma (2017) demonstrated our limitations in predicting intensification, [...]

Keywords Plant growth-promoting bacteria; Metal mobilization; Increased temperature; Phytoremediation; Abiotic stress; Zea mays Highlights * Bacillus cereus TCU11 showed high levels of resistance to abiotic stresses. * TCU11 increased plant growth and tolerance to HM and IAT stress. * It enhanced phenolics, proline, and antioxidant enzymes, but reduced MDA in plants. * B. cereus improved HM phytoremediation under IAT condition. Abstract The co-occurrence of environmental stresses such as heavy metals (HM) and increased atmospheric temperature (IAT) pose serious implications on plant growth and productivity. In this work, we evaluated the role of plant growth-promoting bacteria (PGPB) and its effectiveness on Zea mays growth, stress tolerance and phytoremediation potential in multi-metal (MM) contaminated soils under IAT stress conditions. The PGPB strain TCU11 was isolated from metal contaminated soils and identified as Bacillus cereus. TCU11 was able to resist abiotic stresses such as IAT (45 [degrees]C), MM (Pb, Zn, Ni, Cu, and Cd), antibiotics and induced in vitro plant growth promotion (PGP) by producing siderophores (catechol and hydroxymate) and indole 3-acetic acid even in the presence of MM under IAT. Inoculation of TCU11 significantly increased the biomass, chlorophyll, carotenoids, and protein content of Z. mays compared to the respective control under MM, IAT, and MM + IAT stress. A decrease of malondialdehyde and over-accumulation of total phenolics, proline along with the increased activity of superoxide dismutase, catalase and ascorbic peroxidase were observed in TCU11 inoculated plants under stress conditions. These results suggested MM and/or IAT significantly reduced the maize growth, whereas TCU11 inoculation mitigated the combined stress effects on maize performance. Moreover, the inoculation of TCU11 under IAT stress increased the MM (Pb, Zn, Ni, Cu, and Cd) accumulation in plant tissues and also increased the translocation of HM from root to shoot except for Ni. The results of soil HM mobilization further indicates that IAT increased the HM mobilizing activity of TCU11, thus increasing the concentrations of bio-available HM in soil. These results suggested that TCU11 not only alleviates MM and IAT stresses but also enhances the biomass production and HM accumulation in plants. Therefore, TCU11 can be exploited as inoculums for improving the phytoremediation efficiency in MM polluted soils under IAT conditions.

Researchers plan to spray sunlight-reflecting particles into the stratosphere, an approach that could ultimately be used to quickly lower the planet's temperature.Researchers plan to spray sunlight-reflecting particles into the stratosphere, an approach that could ultimately be used to quickly lower the planet's temperature., Author(s): Jeff TollefsonAuthor Affiliations:First sun-dimming experiment will test a way to cool Earth Frank Keutsch, Zhen Dai and David Keith (left to right) in Keutsch's laboratory at Harvard University. [see [...]

Highlights * The local time variation of cloud optical depth is examined from THEMIS observations. * Clouds have higher optical depth during the evening than earlier in the afternoon. * After sunset, clouds expand to locations where clouds were not present earlier. Abstract The move of the Odyssey spacecraft during Mars Years 31 and 32 to an orbit with local time near 7:00 AM and PM has enabled the systematic retrieval of water ice cloud optical depth using THEMIS thermal infrared images at a time of day not accessible from Mars Global Surveyor, Mars Reconnaissance Orbiter, or previous Odyssey observations. Because water ice clouds form by condensation, relatively small changes in atmospheric temperature can cause clouds to form or sublimate quickly, and there can be large changes in water ice cloud optical depth over the course of a day. Retrievals of water ice cloud optical depth using THEMIS observations show significant differences in cloud locations and optical depth as a function of local time and season. Cloud optical depth generally increases from the earliest (14:30) to latest (19:30) observations. During the aphelion season the increase from afternoon to evening is primarily associated with the thickening of existing clouds, while during the equinoctial and perihelion seasons there is a proportionally greater increase associated with the formation of clouds in the evening at locations where clouds were not present during the afternoon. Author Affiliation: NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States * Code 693, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States Article History: Received 17 January 2019; Revised 26 April 2019; Accepted 10 June 2019 Byline: Michael D. Smith [Michael.D.Smith@nasa.gov] (*)

Keywords Soil gas monitoring; Vadose zone; Natural CO.sub.2 variation Highlights * Background variations of CO.sub.2 concentration must be accounted for to evaluate leaking from storage. * Large daily swings in naturally produced gas concentration were consistently observed. * Multi-level monitoring data shows gas circulation in wells due to natural causes. * Must consider diurnal and weather patterns when conducting gas sampling in wells. Abstract Multi-level wells screened at different depths in the vadose zone were installed and used for CO.sub.2 and carbon isotope monitoring. Well CO.sub.2 time series data were collected along with subsurface and atmospheric parameters such as air pressure, temperature, wind speed, and moisture content. Our aim was to determine the natural factors affecting the variation of CO.sub.2 concentration and how the influence of these factors varies with time of day and seasons of the year. We were motivated to understand the cause and extent of CO.sub.2 natural fluctuations in vadose zone wells in order to separate natural variation from signals due to anthropogenic CO.sub.2 leaks anticipating future monitoring using these wells. Variations of seasonal mean and variance of CO.sub.2 concentrations at different depths seem to follow the diurnal trend of subsurface temperature changes that reflect the atmospheric temperature but with time delay and amplitude damping due to heat transport considerations. The temperature in the ground lags behind the change in the atmospheric temperature, thus, the deeper the depth, the longer the time delay and the smaller the amplitude of the change. Monitored seasonal variation as shown in Appendix A shows the temperature-dependent depth-dependent CO.sub.2 production in the soil zone indicating higher CO.sub.2 concentrations in the summer and fall seasons with high concentrations ranging between 10,990 and 51,600 ppm from spring to summer, and 40,100 and 17,760 ppm from fall to winter. As the temperature in the organic-rich topsoil layer changes from daytime to nighttime, the concentration of CO.sub.2 in the soils also changes dynamically in response to chemical and biological reactions. When a screened well is installed in the vadose zone the dynamic temporal and depth difference in CO.sub.2 production is further complicated by upward (out of the subsurface) or downward (into the subsurface) gas flow, which will amplify or attenuate the temporal and vertical biochemically produced differences. Nested wells screened at different depths in the vadose zone and wells fully screened through the vadose zone were used for comparison. In addition, experiments changing the well from open to surface air to sealed at the top were conducted. The flow rates of inhaled (downward) and exhaled (upward) gas were estimated based on multi-level monitoring data. Based on time-series monitoring data, we proposed a time-dependent conceptual model to explain the changes of CO.sub.2 concentration in wells. The conceptual model was tested through analytical model computations. This conceptual model of natural variation of CO.sub.2 will be helpful in utilizing the vadose zone well as a method for monitoring CO.sub.2 leakage from subsurface storage or anthropogenic CO.sub.2 -producing activities. Author Affiliation: (a) School of Earth and Environmental Sciences, Seoul National Univ., Seoul, 151-747, South Korea (b) Redox Tech, LLC, 200 Quade Drive, Cary, NC, 27513, USA (c) Division of Earth and Environmental Sciences, Ochang Center, Korea Basic Science Institute, South Korea * Corresponding author. Article History: Received 1 November 2018; Revised 8 January 2019; Accepted 16 January 2019 Byline: Won-Tak Joun (a), Joseph Rossabi (b), Woo-Jin Shin (c), Kang-Kun Lee [kklee@snu.ac.kr] (a,*)

Byline: Greg A. Barron-Gafford, Russell L. Scott, G. Darrel Jenerette, Erik P. Hamerlynck, Travis E. Huxman, Matthew Turnbull Keywords: eddy covariance; landscape position; mesquite (Prosopis velutina); photosynthesis; plant-climate interactions; semi-arid; temperature optima; vegetation change; woody plant encroachment Summary * Many regions of the globe are experiencing a simultaneous change in the dominant plant functional type and regional climatology. We explored how atmospheric temperature and precipitation control leaf- and ecosystem-scale carbon fluxes within a pair of semi-arid shrublands, one upland and one riparian, that have undergone woody plant expansion. * Through a combination of leaf-level measurements on individual bunchgrasses and mesquites shrubs and ecosystem-scale monitoring using eddy covariance techniques, we sought to quantify rates of net carbon dioxide (CO.sub.2) flux, CO.sub.2 flux temperature sensitivity and the responsiveness of these parameters to seasonal rains and periods of soil dry-down. * We found significant differences in physiological acclimation between the two plant functional types, in that the shrubs consistently conducted photosynthesis across a broader temperature range than co-occurring grasses during dry periods, yet maximum photosynthetic rates in grasses were twice that of mesquites during the wetter monsoon season. Landscape position modulated these temperature sensitivities, as the range of functional temperatures and maximum rates of photosynthesis were two to three times greater within the riparian shrubland in dry times. * Also, it was unexpected that ecosystem-scale CO.sub.2 uptake within both shrublands would become most temperature sensitive within the monsoon, when mesquites and grasses had their broadest range of function. This is probably explained by the changing contributions of component photosynthetic fluxes, in that the more temperature sensitive grasses, which had higher maximal rates of photosynthesis, became a larger component of the ecosystem flux. * Synthesis: Given projections of more variable precipitation and increased temperatures, it is important to understand differences in physiological activity between growth forms, as they are likely to drive patterns of ecosystem-scale CO.sub.2 flux. As access to stable subsurface water declines with decreased precipitation, these differential patterns of temperature sensitivity among growth forms, which are dependent on connectivity to groundwater, will only become more important in determining ecosystem carbon source/sink status.