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Identification of representative segment of root for colour determination of carrot

100%

Jaros M. , Słowik M. , Golisz E. , Janaszek-Mańkowska M.

tom nr 22(2)

109--118

The aim of the work was to verify hypothesis that colour of longitudinal section of carrot root may be represented by a selected segment of root or a cross-section. An image analysis was based on image data obtained for longitudinal sections of carrot roots using flatbed scanner and graphics editing software. Colour images were acquired into sRGB colour space and converted to CIE Lab. Sixteen segments of equal height were separated over whole length of root image. The colour difference metric was determined to present how colour of each segment differs from the mean colour of whole root. The root section was considered to be representative for whole root if colour difference metric was the least. The analysis of results confirmed a research hypothesis and allowed for finding representative section which was located at 10⁄16 of total root length measuring from the carrot root head.

Early detection of phosphorus deficiency stress in cucumber at the cellular level using chlorophyll fluorescence signals

63%

Sieczko L. , Dąbrowski P. , Kowalczyk K. , Gajc-Wolska J. , Borucki W. , Janaszek-Mańkowska M. , Kowalczyk W. , Farci D. , Kalaji H. M.

tom Special Issue

176--186

Abiotic stressors contribute to growth restriction and developmental disorders in plants. Early detection of the first signs of changes in plant functioning is very important. The objective of this study was to identify chlorophyll fluorescence parameters that change under phosphorus deficiency stress in cucumber. In this work, a trail to study the early changes caused by phosphorus deficiency in cucumber plants by analysing their photosynthetic performance is presented. Chlorophyll-a fluorescence (ChF) parameters were measured every 7 days for a period of 28 days. Measurements were made separately on young and old leaves and on cucumber fruit. Parameters that decreased during the stress were: p2G, PIabs, PItotal, REo/CSo, and TRo/CSo. P deficiency decreased total electron carriers per RC (ECo/RC), yields (TRo/ABS (Fv/Fm), ETo/TRo, REo/ETo, ETo/ABS and REo/ABS), fluxes (REo/RC and REo/CSo) and fractional reduction of PSI end electron acceptors, and damaged all photochemical and non-photochemical redox reactions. Principal component analysis revealed a group of ChF parameters that may indicate early phosphorus deficiency in cucumber plants. Our results are used in the discovery of sensitive bioindicators of phosphorus deficiency in cucumber plants. Most JIP test parameters are linked to mathematical equations, so we recommend using of advanced statistical tools, such as principal component analysis, which should be considered very useful for stress identification. It has also been shown to be more effective in multivariate methods compared to univariate statistical methods was demonstrated.