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

Abstract

Abstract. Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the 10 relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure and the impact of shaking as an intermediate step during 15 extraction. The analyses were conducted on four different types of biocrusts. Our results show, that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained with dimethyl sulfoxide (DMSO) as solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen-and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss-and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of 20 green algal lichen-and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest to insert an intermediate shaking step for complete chlorophyll extraction (see supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of studies conducted across all continents.

Properties of Salvia officinalis L. and Thymus serpyllum L. Extracts Free and Embedded into Mesopores of Silica and Titania Nanomaterials

“…The UV-vis spectrum of each sample was recorded, and the solution absorbance was measured at 665 nm, 649 nm, and 750 nm. The chlorophyll a and b contents were computed using the Ritchie’s equations: Ch-a = 13.5275 × (A 665 − A 750 ) − 5.201 × (A 649 − A 750 ) × f × S Ch-b = 22.4327 × (A 649 − A 750 ) − 7.0741 × (A 665 − A 750 ) × f × S where Ch-a—chlorophyll a in µg, Ch-b—chlorophyll b in µg, A—the solution absorbance at a certain wavelength, f—dilution factor, and S—volume of solvent (ethanol or ethanol–water = 4/1) [ 30 ].…”

Ecophysiological properties of three biological soil crust types and their photoautotrophs from the Succulent Karoo, South Africa

“…After finalization of the measurements, the biocrust fractions (photoautotrophic components and remaining substrate) were dried in an oven at 60°C and total dry weight was determined. Chlorophyll extraction was performed according to the method described by Caesar et al (2018; see supplement for methods description), but without intermediate shaking, using Dimethylsulfoxide (DMSO) plus a spatula tip of CaCO 3 to avoid acidification and concomitant phaeophytinization of chlorophyll (Ronen and Galun 1984). After spectrophotometry, the chlorophyll a (Chl a ) content was calculated according to Arnon et al 1974, whereas chlorophyll a + b (Chl a + b ) was determined according to Lange (pers.…”

“…comm. ;Weber et al 2013;Caesar et al 2017). CO 2 gas exchange measurements in the field CO 2 gas exchange measurements in the field were performed at night, since daytime temperatures were too high and fluctuations were too large to allow measurements at a fixed temperature.…”

New In Vitro Model of Oxidative Stress: Human Prostate Cells Injured with 2,2-diphenyl-1-picrylhydrazyl (DPPH) for the Screening of Antioxidants

“…031218). Microalgal powder was resuspended in DMSO, vortexed and sonicated for three times, allowing extraction of pigments [ 48 ]. All samples were manipulated in dark conditions and prepared a few minutes before treatments.…”