The IP amplitude of the fluorescence rise OJIP is sensitive to changes in the photosystem I content of leaves: a study on plants exposed to magnesium and sulfate deficiencies, drought stress and salt stress

Abstract

The hypothesis that changes in the IP amplitude of the fluorescence transient OJIP reflect changes in leaf photosystem I (PSI) content was tested using mineral-deficient sugar beet plants. Young sugar beet plants (Beta vulgaris) were grown hydroponically on nutrient solutions containing either 1 mM or no Mg(2+) and 2.1 µM to 1.88 mM SO(4)(2-) for 4 weeks. During this period two leaf pairs were followed: the already developed second leaf pair and the third leaf pair that was budding at the start of the treatment. The IP amplitude [ΔF(IP) (fluorescence amplitude of the I-to-P-rise) and its relative contribution to the fluorescence rise: ΔV(IP) (amplitude of the relative variable fluorescence of the I-to-P-rise = relative contribution of the I-to-P-rise to the OJIP-rise)] and the amplitude of the transmission change at 820 nm (difference between all plastocyanin and the primary electron donor of photosystems I oxidized and reduced, respectively) relative to the total transmission signal (ΔI(max) /I(tot)) were determined as a function of the treatment time. Correlating the transmission and the two fluorescence parameters yielded approximately linear relationships in both cases. For the least severely affected leaves the parameter ΔV(IP) correlated considerably better with ΔI(max) /I(tot) than ΔF(IP) indicating that it is the ratio PSII:PSI that counts. To show that the relationship also holds for other plants and treatments, data from salt- and drought-stressed plants of barley, chickpea and pea are shown. The relationship between ΔV(IP) and PSI content was confirmed by western blot analysis using an antibody against psaD. The good correlations between ΔI(max) /I(tot) and ΔF(IP) and ΔV(IP) , respectively, suggest that changes in the IP amplitude can be used as semi-quantitative indicators for (relative) changes in the PSI content of the leaf.

Photosynthetic proton and electron transport in wheat leaves under prolonged moderate drought stress

“…The decrease of IP-amplitude is typical for drought stress [67]; however, in some species it occurs only at severe drought stress [68] and it disappears after rehydration [69]. Although the full interpretation of J-I-P kinetics is rather complicated [70,71], the IP amplitude was suggested to be a measure of relative abundance of PSI with respect to PSII [72,73], and its decrease was previously ascribed to decrease of PSI content in leaves [67,74]. In our experiment (Fig.…”

Chlorophyll a fluorescence as a tool to monitor physiological status of plants under abiotic stress conditions

“…in PSI (Schreiber et al 1989;Schansker et al 2003). The I-P phase seems to be related to the content of PSI reaction centers (Ceppi et al 2012) or availability of linear electron transport as determined by 820-nm transmission measurements (Zivcak et al 2014a). For example, the extent of the I-P loss in barley varieties depends on their drought tolerance (Oukarroum et al 2009;Ceppi et al 2012).…”

“…The I-P phase seems to be related to the content of PSI reaction centers (Ceppi et al 2012) or availability of linear electron transport as determined by 820-nm transmission measurements (Zivcak et al 2014a). For example, the extent of the I-P loss in barley varieties depends on their drought tolerance (Oukarroum et al 2009;Ceppi et al 2012). ChlF is emitted following a dark-to-light transition of a photosynthetic sample, while delayed fluorescence emission (DF) occurs during light-to-dark transitions (Goltsev et al 2009;Strasser et al 2010;Kalaji et al 2012).…”

Magnesium deficiency decreases biomass water-use efficiency and increases leaf water-use efficiency and oxidative stress in barley plants

“…Magnesium is essential for chlorophyll synthesis and up to 10 % of total Mg can be associated with chlorophyll (Wilkinson et al 1990). Furthermore, Mg is important for grana stacking in chloroplasts (Hall et al 1972;Ceppi et al 2012) that may adversely affect photosynthetic performance of plants suffering from low Mg supply. It was reported that the degree of stacking increases with increasing Mg concentrations (Stys 1995) and Mg deficiency leads to disruption of grana stacks (Hall et al 1972).…”