Measurements of primary biological aerosol particles and ice nuclei at the Amazon Tall Tower Observatory.

International audienc

Abiotic stress responses in plants - present and future

Drought, cold, high-salinity and heat are major abiotic stresses that severely reduce the yield of food crops worldwide. Traditional plant breeding approaches to improve abiotic stress tolerance of crops had limited success due to multigenic nature of stress tolerance. In the last decade molecular techniques have been used to understand the mechanisms by which plants perceive environmental signals and further their transmission to cellular machinery to activate adaptive responses. This knowledge is critical for the development of rational breeding and transgenic strategies to impart stress tolerance in crops. Studies on physiological and molecular mechanisms of abiotic stress tolerance have led to characterisation of a number of genes associated with stress adaptation. Techniques like microarrays have proven to be invaluable in generating a list of stress related genes. Some of these genes arc specific for a particular stress while others are shared between various stresses. Interestingly, a number of genes are shared in abiotic and biotic stress responses

STRUCTURAL PROPERTIES OF CoFe2-xCexO4 (x =0.00 AND 0.02) NANOPARTICLES USING XRD AND FTIR ANALYSIS

In this communication, we report the synthesis of Ce doped cobalt ferrite having the formula CoFe2-xCexO4 (x =0.00 and 0.02) using sol-gel autocombustion method and investigations of various properties to understand the role of Ce on the structural, morphological, electrical, optical and magnetic properties of cobalt ferrite. X-ray diffraction technique confirms the formation of single phase cubic spinel structure associated with the prepared samples. Various structural parameters were obtained and their co-relation with Ce was examined. The crystallite size obtained from Debye Scherrer formula suggests that the prepared samples are nanocrystalline in nature. The infrared spectra of CoCexFe2-x04 (x =0.00 and 0.02) in the frequency range of 400 to 4000 cm-1 . The IR has detected that the intrinsic and extrinsic vibrations of CoFe2- xCexO4 nanoparticles; v2 = 390 - 406 cm–1 and v1 = 548 - 554 cm–

Thermodynamics and Microphysics Relation During CAIPEEX-I

Influence of the environmental thermodynamics on the microphysics of deep cumulus clouds over different parts of India is studied using in situ airborne observations from the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) during 2009. This study provides an understanding of the thermodynamics–microphysics relation over the Indian summer-monsoon region. Relatively stronger updraft and turbulence are noted in the pre-monsoon cloud base layers compared to that of the monsoon clouds. It is illustrated from the in situ observations as well as from a microphysical parcel model that the vertical variation of cloud droplet number concentration (CDNC) has a well-defined peak at a certain height above the cloud base. This elevated CDNC peak is found to be connected with the cloud parcel buoyancy and cumulative convective available potential energy (cCAPE). Higher parcel buoyancy above the cloud base of dry pre-monsoon clouds is associated with stronger in-cloud updraft velocity, higher supersaturation and higher droplet number concentration (in addition to aerosol effect). Higher adiabatic fraction and lower entrainment rate are observed in polluted clouds where boundary layer moisture is low, compared to clean clouds. Relative dispersion of droplet size distribution is found to vary concurrently with air mass characteristics and aerosol number concentration observed over different locations during the experiment. Aerosol–precipitation relationships are also investigated from the observation. Maximum reflectivity and rain rates showed a direct link with boundary layer water vapor content rather than with subcloud aerosol number concentration

Characteristics of CCN activation and cloud microphysics over the east coast of India during the Northeast Monsoon onset

Airborne observations conducted during the Northeast Monsoon onset as part of the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX 2011) are used to link the activation properties of aerosols with the observed cloud microphysics. This study illustrates the significant spatial variability in the aerosol spectrum, cloud condensation nuclei (CCN) activation characteristics, and the cloud droplet spectral properties over a coastal and an inland location. High concentrations of Aitken mode and black carbon aerosols were observed in the free troposphere and are attributed to the convectively transported smoke and aerosols from the coastal boundary layer. The assumption of an internally mixed organic and inorganic aerosol composition provided a better CCN closure over assumptions of either purely organic or purely inorganic aerosols. The coastal clouds were equally polluted as the inland clouds with high cloud droplet number concentrations near the cloud base. The vertical distribution of cloud droplet spectral characteristics was similar in both coastal and inland clouds. An increase in droplet number concentration up to 2 km above the cloud base indicated a prominent influence of submicron particles on the cloud microphysical parameters. Evidence for an enhanced concentration of supercooled drops above the freezing level up to temperatures below −12 °C is documented. The secondary ice production was evident through observations of graupel and snow particles. Heavy loading of aerosols near the cloud base leads to enhanced mixed-phase processes in these clouds

Seed Reserve Utilization and Seedling Growth of Treated Seeds of Mountain Rye (Secale Montanum) as Affected by Drought Stress

ABSTRACT. The environmental stress such as, drought are serious obstacles for field crops in further areas of the world, especially in arid and semiarid regions. In order to investigate drought stress on seed reserve utilization and seedling growth of treated seeds of mountain rye (Secale montanum), an experiment was carried out. Factorial experiment was carried out in completely randomized design with three replications. The first factor was the seed treatments (unpriming, hydropriming and osmopriming) and the second factor was drought stress. To create drought stress, polyetylenglycol 6000 (PEG 6000) in osmotic levels at 0 (as control),-0.4,-0.8,-1.2 and-1.6 MPa were used. The results indicated that for these traits: germination percentage (GP), timson index (TI), energy of germination (EG), weight of utilized (mobilized) seed (WMSR), seed reserve utilization efficiency (SRUE), seedling dry weight (SLDW), and seed reserve depletion percentage (SRDP), was a significant treatment × drought interaction. Thus hydropriming and osmopriming improvement study traits in Secale montanum under drought stress. While in higher osmotic pressure the highest seed reserve utilization were obtained from osmopriming