The use of black leaf-clips for dark adaptation under high solar radiation conditions is reported to underestimate the maximum quantum yield of PSII photochemistry (Fv/Fm) measured by the continuous-excitation fluorometer Pocket PEA. The decrease in Fv/Fm was due to a rise in minimum fluorescence emission (F0), probably resulting from increased leaf temperature (Tl). In
field-grown tomato and pepper, fluorescence parameters and Tl in the region covered by the black leaf clip were measured in clipped leaves exposed to solar radiation during dark adaptation (clipped-only leaves) and in clipped leaves protected from solar radiation by aluminium foil (shrouded clipped leaves). Results confirmed significant Fv/Fm underestimates in clipped-only leaves primarily due to increased F0. In one tomato experiment, Tl increased from 30 to 44.5°C in clipped-only leaves, with a negligible rise in shrouded clipped leaves. In two respective pepper experiments, Tl in clipped-only leaves increased from 27 to 36.2°C and 33 to 40.9°C. Based on the results of this study, a clip-effect parameter (PCE) on fluorescence emission is proposed as the difference for Fv/Fm (or -F0/Fm) between shrouded clipped leaves and clipped-only leaves, which resulted to be 0.706 for tomato, and 0.241 and 0.358 for the two pepper experiments., P. Giorio ... [et al.]., and Obsahuje bibliografii
The article presents an evaluation and quantification of the reliability interval of measurement parameters based on the theory expressing an uncertainty in measurement as was recommended by the CIPM (Comité International des Poids et Measures) in 1993. Numerical values of the reliability interval are quantified by statistical methods. the quantification technique for reliability interval has three components. the reliability interval ue is obtained as a statistical calculation of measurement parameters xi using the reliability coefficient e = 2.72. the combined reliability interval uce is obtained as a statistical (square) sum of reliability interval ue and uncertainty of parameters measuring device ub. the reliability interval of measurement parameters Ue is obtained as a multiplication of combined reliability interval uce with coverage factor k relevant to the probability P. the reliability interval of measurement parameters is used for evaluation and managing technology processes with aim to secure the quality of products and the efficiency of production. and Článok predstavuje postup hodnotenia a kvalifikácie intervalu spoľahlivosti meraných parametrov založenom na teórii vyjadrenia neistoty merania doporučeného CIPM (Comité International des Poids et Measures) (Medzinárodný výbor pre váhy a meranie) v roku 1993. Číselné hodnoty intervalu spoľahlivosti získame štatistickými metódami. Technika kvantifikácie má tri zložky. Interval spoľahlivosti označený symbolom ue získame štatistickým výpočtom meraných parametrov xi použitím koeficientu spoľahlivosti e = 2,72. Kombinovaný interval spoľahlivosti označený symbolom uce získame štatistickým sčítaním intervalu spoľahlivosti ue s neistotou merania meracieho prístroja uB (merací prístroj na meranie parametrov). Interval spoľahlivosti meraných parametrov označený symbolom Ue získame násobením kombinovaného intervalu spoľahlivosti faktorom pokrytia k pri zodpovedajúcej pravdepodobnosti P. Interval spoľahlivosti meraných parametrov pokrýva rozptyl meraných parametrov so stanovenou pravdepodobnosťou. Interval spoľahlivosti meraných parametrov použijeme pri hodnotení a riadení technologických procesov s cieľom zabezpečenia kvality produktov a efektívnosti výroby.