Comprehensive assessment of extraction methods for plant tissue samples for determining sodium and potassium via flame photometer and chloride via automated flow analysis^#

Abstract

Background and aims Determination of sodium (Na), potassium (K), and chloride (Cl) content in plant tissue is required for research related to salinity resistance in plants. Standard methods are available to extract these elements from dried plant material, but these methods are often costly, relatively dangerous, or time consuming. Many authors modify extraction methods substantially without proof of comparability across methods. Methods Here, dried tissues of two varieties of rice and three varieties of sweet potato subjected to salt stress were extracted for Na and K using six different extraction methods (1–6) and for Cl using three Cl‐free extraction methods (2, 4, 5) for Cl: (1) the VDLUFA standard method, consisting of ashing, and heat extraction in hydrochloric acid (HCl), (2) hot water pressure extraction via autoclave, (3) extraction with 1 M HCl overnight, (4) hot water extraction at 90°C for 1 h, (5) acetic acid extraction in hot 1 M acetic acid for 2 h, and (6) extraction with a microwave using nitric acid. Na and K were determined via flame photometer and Cl via automated flow analysis. Results Na and K concentrations varied little among different extraction methods as compared to the VDLUFA standard method, and for Cl, all extractions resulted in similar tissue Cl concentrations. Conclusions Ultimately, the choice of extraction method depends on the instrumentation and lab equipment necessary, available budget, the available amount of sample, and time constraints which should be decided according to the experiment. For reasons of comparability among publications, methods applied should be clearly described since results vary depending on the method chosen.

Potassium content is the main driver for salinity tolerance in sweet potato before tuber formation

“…A high‐tissue K content under nonsaline levels indicates high yield and a small difference in K content at the critical root zone salinity, here defined as 75 mM NaCl, indicates salt tolerance. Therefore, the system we propose for quickly screening large numbers of genotypes consists of a hydroponic system using Yoshida nutrient solution (Yoshida et al, 1976), vine cuttings of three nodes (one in the solution, two above the solution), nonsaline growth for 2 weeks and exposure of half of the plants to 75 mM NaCl in the root zone for 3 weeks, sampling of the above‐ground biomass for all plants and analyze the tissue K content according to Asch et al (2022).…”

“…Following the extraction method described by Asch et al (2022), 10 ml of deionized water was added to approximately 0.1 g of ground dry material in 15 ml centrifuge vials (Roth GmbH & Co. KG) and shaken until thoroughly homogenized. Samples were heat extracted with an autoclave (SanoClav MMCS) at 120°C for 60 min and centrifuged (Allegra X‐15®, Beckman Coulter GmbH) for 5 min.…”

“…Sodium and potassium were determined by a flame photometer (Jenway, PFP 7). Chloride was determined from the same sample with an autoanalyser (Autoanalyser II, Technicon, America) according to Asch et al (2022) and standard solutions.…”

Development and Application of Portable Reflectometric Spectroscopy Combined with Solid-Phase Extraction for Determination of Potassium in Flue-Cured Tobacco Leaves

“…The minerals and trace elements in plant tissue are usually determined following wet digestion or high temperature (450 °C) ashing techniques involving digestion with single acid, triacid, or diacid mixtures (HNO 3 , H 2 SO 4 , and HClO 4 ) or heating dissolution with HCl, but these methods are often costly, relatively dangerous, or time consuming due to the use of strong acid, large amounts of dry sample. , K in plant tissue is not bound to organic compounds and occurs in soluble forms, thus indicating the ease of its extractability . Recently, a nondigestion extraction method was proposed for the estimation of plant K content using solution extraction with water, acetic acid, CaCl 2 , salt EDTA, or ammonium/magnesium acetate . Compared with digestion and ashing techniques, more sample pretreatment can be handled in the same amount of time.…”

Salinity effects on the activities of ROS scavenging enzymes in leaves of two sweet potato clones

“…Samples were oven dried at 60°C for 72 h, dry weight was recorded and samples were milled to a fine powder (5 and 3 mm stainless steel balls). About 0.1 g of the sample material was weighed in 15 mL centrifuge vials (Roth GmbH& Co.KG) and 10 mL of deionized H 2 O was added for the water extraction in an autoclave as described by Asch et al (2022). Samples were autoclaved for 60 min at 120°C and then centrifuged for 5 min at 4000 U min −1 .…”