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Vývoj metodologické a technologické platformy pro neinvazivní odhad fenolických látek v listech a bobulích
ŠEBELA, David
Plant optical signals can serve as important source of information about biochemical and physiological processes in plants. These signals are influenced by compounds synthesized by plants during primary or secondary metabolism and thus, can also serve as their qualitative and quantitative indicators. Light reaching plant surface (leaf or fruit) can undergo three main pathways- it can be (i) reflected, (ii) absorbed or it can (iii) transmit through plant material. The probability of these three processes depends on particular wavelength of incident irradiation and on the morphological characteristics of plant tissues themselves. As such, plant contains various spectrum of photosynthetic pigments and fluorescent compounds which can either reflect, absorb or pass incident irradiation through at specific wavelengths. Biophysical techniques working with these optical properties of plant pigments and/or other compounds have become universal and common tool in basic and applied research. To quote some example, chlorophyll fluorescence imaging, UV induced fluorescence or spectroscopic techniques are on the top of interest thanks to its non-invasive nature, allowing maintain the integrity of measured cells or the whole plant constituents. The main aim of this thesis is to provide a comprehensive study on the possibility of non-invasive monitoring of phenolic compounds in the leaves and fruits.
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High night temperature-induced accelerated maturation of rice panicles can be detected by chlorophyll fluorescence
Šebela, David ; Quiňones, C. ; Olejníčková, Julie ; Jagadish, K. S. V.
Rice panicle maturation is considered to be highly sensitive to environmental conditions. Since one of the factors accompanying global climate change is increases in minimum night temperatures more pronounced than those in maximum day temperatures, the effect of high night temperature (HNT) on rice panicle maturation was investigated. Two rice genotypes with contrasting HNT responses, N22 (highly tolerant) and Gharib (susceptible), were exposed to control temperatures (ca 23°C) and HNTs (ca 29°C) from flowering until maturity. Loss of photosynthetic activity and/or pigments during rice panicle maturation were evaluated temporally by measuring (i) effective quantum yield of photosystem II efficiency (ΦII), and (ii) steady-state chlorophyll fluorescence level (FS). To prove the accuracy of the new approach presented in this study, several vegetative indices were calculated from reflectance measurements and correlated with fluorescence parameters. It has been observed that ΦII tracks the accelerated maturation of rice panicles exposed to HNT better than does FS. Employing a newly identified chlorophyll fluorescence-based parameter could potentially enable larger genetic diversity scans and identification of novel genotypes with longer panicle maturation periods so as to increase rice yields directly under field conditions.
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