UTILIZATION OF INFRARED THERMOGRAPHY AND LEAF REFLECTANCE INDICES IN EVALUATION OF EFFECTS THE TREATMENT OF SUNFLOWER (HELIANTHUS ANNUUS L.) BY BIOLOGICALLY ACTIVE COMPOUNDS

The effects of biologically active compounds (Route and Sunagreen) on physiological fitness of three sunflower hybrids (NK Kondi, NK Dolbi a NK Tristan) were carried out during the whole growing season in vegetation polyfactorial experiments. Evaluation of the sunflower physiological fitness was realized by non-destructive technique of measuring the temperature difference (∆T) with an infrared thermography and simultaneous measurement of the leaf reflectance indices NDVI (normalized difference vegetation index) and PRI (photochemical reflectance index). In this paper we discuss the ontogenetic changes in the parameters ∆T, NDVI and PRI with emphasis on changes in weather conditions. We also investigated the potential effects of foliar applied biologically active compounds on plants and sensitivity of sunflower hybrids to their application. The results confirmed the typical ontogenetic changes of individual assessment parameters that reflect the physiological processes of plant during the growing season. In this vegetation period which was characterized by high precipitation in summer, the most sensitive measure parameter was ΔT. All sunflower hybrids significantly (p <0.05) responded to the treatment by Route, particularly in the reproductive stage of ontogeny (treatment by Route the average ΔT was -4.5 to -5.2 oC and in untreated plants -2.3 to -3.8 oC). This result indicates on a greater cooling effect of transpiration and thus a higher stomatal conductivity induced by Route treatment. Sunflower plants treated by Sunagreen showed in ΔT statistically significant response only in hybrid NK Tristan at the last phase of ontogeny. Reflectance indices NDVI and PRI, which correlates with the photosynthetic efficiency of plants, proved as the less sensitive parameters describing the effects of biologically active substances on sunflower hybrids. Results showed that the PRI index increased during plant ontogeny with a subsequent decrease in the maturing of achenes but we not observed the statistically significant positive effects of biologically active substances on physiological fitness of sunflower hybrids

Design of Document Databases: What can we Learn from Object-Relational Databases?

The emergence of applications that manage very large volumes of semi-structured data is driving the popularity of document databases such as MongoDB. One of the main appeals of document databases is schema flexibility as this allows the schema to be biased towards a particular set of applications. This approach is favoured by many developers who regard document databases to be essentially schema-less and focus on performance and scalability issues rather than ensuring that the schema can be gracefully evolved as application requirements change. There is evidence that many developers use ad-hoc methods based on heuristics rather than well-established design principles, potentially creating designs that cause data modification anomalies that can lead to the loss of data consistency. In this paper we argue that the design of document databases is not an entirely new problem and that existing object-relational database design methods can be adapted for the design of document databases. We describe a design approach that is an adaptation of object-relational design and serves as a framework for making informed decisions about alternative design strategies for document databases

Evaluation of Hyperspectral Reflectance Parameters to Assess the Leaf Water Content in Soybean

Nondestructive assessment of water content and water stress in plants is an important component in the rational use of crop irrigation management in precision agriculture. Spectral measurements of light reflectance in the UV/VIS/NIR region (350&ndash;1075 nm) from individual leaves were acquired under a rapid dehydration protocol for validation of the remote sensing water content assessment in soybean plants. Four gravimetrical approaches of leaf water content assessment were used: relative water content (RWC), foliar water content as percent of total fresh mass (FWCt), foliar water content as percent of dry mass (FWCd), and equivalent water thickness (EWT). Leaf desiccation resulted in changes in optical properties with increasing relative reflectance at wavelengths between 580 and 700 nm. The highest positive correlations were observed for the relations between the photochemical reflectance index (PRI) and EWT (rP = 0.860). Data analysis revealed that the specific water absorption band at 970 nm showed relatively weaker sensitivity to water content parameters. The prediction of leaf water content parameters from PRI measurements was better with RMSEs of 12.4% (rP = 0.786), 9.1% (rP = 0.736), and 0.002 (rP = 0.860) for RWC, FWCt, and EWT (p &lt; 0.001), respectively. The results may contribute to more efficient crop water management and confirmed that EWT has a statistically closer relationship with reflectance indices than other monitored water parameters

Genotypically Identifying Wheat Mesophyll Conductance Regulation under Progressive Drought Stress

AbstractPhotosynthesis limitation by CO2 flow constraints from sub-stomatal cavities to carboxylation sites in chloroplasts under drought stress conditions is, at least in some plant species or crops not fully understood, yet. Leaf mesophyll conductance for CO2 (gm) may considerably affect both photosynthesis and water use efficiency in plants under drought conditions. The aim of our study was to detect the responses of gm in leaves of four winter wheat (Triticum aestivum L.) genotypes from different origins under long-term progressive drought. Based on the measurement of gas-exchange parameters the variability of genotypic responses was analyzed at stomatal (stomata closure) and non-stomatal (diffusional and biochemical) limits of net CO2 assimilation rate (AN). In general, progressive drought caused an increasing leaf diffusion resistance against CO2 flow leading to the decrease of AN, gm and stomatal conductance (gs), respectively. Reduction of gm also led to inhibition of carboxylation efficiency (Vcmax). On the basis of achieved results a strong positive relationship between gm and gs was found out indicating a co-regulation and mutual independence of the relationship under the drought conditions. In severely stressed plants, the stomatal limitation of the CO2 assimilation rate was progressively increased, but to a less extent in comparison to gm, while a non-stomatal limitation became more dominant due to the prolonged drought. Mesophyll conductance (gm) seems to be a suitable mechanism and parameter for selection of improved diffusional properties and photosynthetic carbon assimilation in C3 plants, thus explaining their better photosynthetic performance at a whole plant level during periods of drought

Applying hyperspectral imaging to explore natural plant diversity towards improving salt stress tolerance

Salinity represents an abiotic stress constraint affecting growth and productivity of plants in many regions of the world. One of the possible solutions is to improve the level of salt resistance using natural genetic variability within crop species. In the context of recent knowledge on salt stress effects and mechanisms of salt tolerance, this review present useful phenomic approach employing different non-invasive imaging systems for detection of quantitative and qualitative changes caused by salt stress at the plant and canopy level. The focus is put on hyperspectral imaging technique, which provides unique opportunities for fast and reliable estimate of numerous characteristics associated both with various structural, biochemical and physiological traits. The method also provides possibilities to combine plant and canopy analyses with a direct determination of salinity in soil. The future perspectives in salt stress applications as well as some limits of the method are also identified. (C) 2016 Elsevier B.V. All rights reserved.</p