Leaf metabolites profiling between red and green phenotypes of Suaeda salsa by widely targeted metabolomics.

The Chenopodiaceae Suaeda salsa (L.) Pall. is a traditional Chinese medicine and food with green and red phenotypes in the Yellow River Delta. We identified 521 metabolites using widely targeted metabolomics, of which 165 were selected as significantly differential metabolites which could be related to the leaf traits of different phenotypes of S. salsa. Two anthocyanins (i.e. cyanidin O-acetylhexoside and delphinidin-3-O-(6'-O-α-rhamnopyranosy l-ß-glucopyranoside)) were responsible for red colour in red leaves of S. salsa. Gallic acid, which existed only in red one, was the main reason for leaf succulence. D-arabitol and ribitol were two significantly upregulated carbohydrates in red phenotype. Four alkaloids (i.e. harmaline, aminophylline, pipecolate and trigonelline) were upregulated in red leaves. Hormonal changed involved a decrease in indoleacetic acid-valine (IAA-Val), N6-isopentenyladenosine-5'-monophosphate (iPRMP), isopentenyladenineriboside (iPR), trans-abscisic acid (S-ABA), salicylic acid O-hexoside, methyl jasmonate, N6-isopentenyladenine (iP), trans-zeatin riboside-O-glucoside iso2, trans-zeatin riboside-O-glucoside, and a tendency for dihydrozeatin 9-O-glucoside (DZ9G) down accumulation. In addition, the regulation of amino acids and lipids also contributed to the adaptation of red phenotype to harsh environment. Generally, our findings provide a comprehensive comparison of the metabolites between two phenotypes of S. salsa and an interpretation of phenotypic differences from the point of metabolomics.

Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Qmax) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p < 0.05). The percentage of phosphorus desorption (Pdes) in the FW soils (7.5-63.5%) was much lower than those in TW (27.7-124.9%) and SW soils (19.2-108.5%). The initial soil organic matter, pH and the exchangeable Al, Fe and Cd contents were important factors influencing P sorption and desorption. The findings of this study indicate that freshwater restoration can contribute to controlling the eutrophication status of water bodies through increasing P sorption.