Functioning of the photosynthetic apparatus under low and high light conditions in chlorotic spruce needles as evaluated by in vivo chlorophyll fluorescence

Abstract

The photosynthetic apparatus rapidly responds to the environmental influences. In vivo chlorophyll fluorescence was applied for the evaluation of photosystem II (PSII) and electron-transport chain functioning and for determination of photochemical and nonphotochemical quenching in chlorotic spruce needles exposed to urban pollution. More injured needles had lower content of chloroplast pigments and changed chloroplast ultrastructure, in comparison with less injured needles. The maximum PSII efficiency was measured in darkadapted samples, whereas other parameters were measured under low and high light conditions (125 and 1400 µ mol photons/(m 2 s), respectively). The PSII efficiency and relative electron transport rate (rel. ETR) were lowered at both irradiance levels while the photochemical quenching was significantly lower only in high light. Nonphotochemical quenching coefficients ( qN ) values were higher at both light levels in more injured needles, however, the difference was insignificant. High nonphotochemical quenching in both needle groups probably made possible the photosynthetic apparatus to function at the high light level. Our results suggested that the lowering of the chlorophyll content could be considered as a protecting event rather than just the consequence of the stress.

Assessing forest health via linking the geochemical properties of a soil profile with the biochemical parameters of vegetation

“…Plant species vary in their ability to withstand exposure to heavy metals from hyperaccumulation known for phytoextraction species to prevention of uptake characteristic for phytostabilization species (Salt et al 1998;Nwoko 2010;Mani et al 2012a, b). Heavy metal contamination and other negative physio-chemical changes under soil conditions, such as low pH, are often a consequence of long-term industrial pollution (Lepedus et al 2005;Tuzhilkina 2009). …”

“…Changes in the contents of important plant compounds can be used as non-specific indicators of plant stress; these include the contents of photosynthetic pigments, phenolic compounds and lignin, as shown for coniferous trees by many authors (e.g., Soukupová et al 2000;Lepedus et al 2005;Tzvetkova and Hadjiivanova 2006). Additionally, these parameters can be monitored by the means of hyperspectral (HS) remote sensing and enable large-scale monitoring of forest health (Campbell et al 2004;Mišurec et al 2012;Kupková et al 2012).…”

“…Particularly, the contents of photosynthetic pigments are closely related to photosynthetic performance and can serve as early-warning symptoms of plant stress, before macroscopic changes are detected (e.g., Lepedus et al 2005;Soukupová et al 2000). The chlorophyll content of needles generally decreases under stress conditions, including nutrient deficiency and the presence of heavy metals (Huang and Tao 2004;Ivanov et al 2011;Maestri et al 2010).…”