Effect of Evernic Acid on Structure of Spinach Chloroplasts

Abstract

Detached leaves of Spinacia olerácea were incubated with evernic acid, the main phenolic substance presen! in Evernia prunastri thalli. This lichen substance produced a decrease in the amount of total chlorophyll and chlorophyll a in treated spinach leaves. Chloroplast structure suffered a decrease in several parameters, i.e. chloroplast área, number of grana, granal width, number of thylakoids per granum and starch contení. The submicroscopic structure of the chloroplast membranes revealed smaller particle diameters in several of the fracture faces in the evernic acid treated samples and even a decrease in the density of partióles in the EFS fracture face. The alterations observed may be related to changes in photosynthetic activity, probably by modification of both photosystem I and photosystem II activities.

Towards a more realistic picture of in situ biocide actions: Combining physiological and microscopy techniques

“…Following Koretrel treatment, the thylakoid lamellae of the chloroplast were indistinguishable by TEM. Considering the important role played by these structures and that their largest particles may be associated with PSII and smallest particles with PSI (Arntzen et al, 1969;Rapsch and Ascaso, 1985), this observation of completely disrupted thylakoids and the ChlaF data obtained by PAM were perfectly consistent with the effects of the biocide. In addition to these effects on the thylakoids, any damage to the pyrenoid will be crucial because it has been shown that, as was demonstrated in lichens, this is the main storage site of ribulose-1,5bisphosphate carboxylase oxygenase (Ascaso et al, 1995).…”

Multispectral fluorescence imaging for detection of bovine faeces on Romaine lettuce and baby spinach leaves

“…Compared to the Romaine lettuce leaves, spinach leaves exhibited relatively higher chlorophyll a fluorescence emissions in the red spectral region. This observation was indicative of the relative chlorophyll contents of the leavesdthe chlorophyll content in spinach is about 1032 mg g À1 while the chlorophyll content in Romaine lettuce is about 360 mg g À1 (Aguero et al, 2008;Rapsch & Ascaso, 1985). The soil spots, though visually similar to the faecal spots, exhibited relatively low to minimal fluorescence emissions throughout the wavelength region under investigation.…”

“…Faecal detection on leafy greens may present some challenges because of the relatively higher concentrations of chlorophylls found in leafy green leaves (as compared to apples) and the close proximity in red fluorescence emission characteristics between the animal faecal matter and chlorophyll a in green leaves. Furthermore, the chlorophyll a content of spinach is approximately 3 times higher than that of Romaine lettuce (Aguero, Barg, Yommi, Camelo, & Roura, 2008;Rapsch & Ascaso, 1985), and spinach leaves exhibit a relatively homogeneous surface while the veined leaves of Romaine lettuce exhibit greater variegation. These leaf characteristics may complicate the detection of faecal contamination by spectral imaging methods.…”

Revisiting chlorophyll extraction methods in biological soil crusts – methodology for determination of chlorophyll <i>a</i> and chlorophyll <i>a</i> + <i>b</i> as compared to previous methods

“…The soil crust samples of the four types (n = 5) were placed in 15 mL screw-cap vials without prior grinding. A spatula tip of MgCO 3 or CaCO 3 was added to avoid acidification and the associated chlorophyll degradation (Weber et al, 2013;Rapsch and Ascaso, 1985). Following this, 6 mL of DMSO (ROTIDRY ® ≥ 99.5 %, ≤ 200 ppm H 2 O, Carl Roth GmbH + Co. KG, Karlsruhe, Germany) were added to the samples.…”